Product Folder Sample & Buy Support & Community Tools & Software Technical Documents LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 LP295x Adjustable Micropower Low-Dropout Voltage Regulators 1 Features 3 Description * * * * * * * * * * * The LP2952 and LP2953 are micropower voltage regulators with very low quiescent current (130 A typical at 1-mA load) and very low dropout voltage (typically 60 mV at light load and 470 mV at 250-mA load current). They are ideally suited for batterypowered systems. Furthermore, the quiescent current increases only slightly at dropout, which prolongs battery life. 1 2.3-V to 30-V Input Voltage Range Output Voltage Adjusts from 1.23 V to 29 V 250-mA Output Current Extremely Low Quiescent Current Low Dropout Voltage Extremely Tight Line and Load Regulation Very Low Temperature Coefficient Current and Thermal Limiting Reverse Battery-Input Protection 50-mA (Typical) Automatic Output Discharge LP2953 Versions Only - Auxiliary Comparator Included With CMOSand TTL-Compatible Output Levels. Can Be Used for Fault Detection, Low-Input Line Detection, and so on. 2 Applications * * * * High-Efficiency Linear Regulator Regulator With Undervoltage Shutdown Low-Dropout Battery-Powered Regulator Snap-ON/Snap-OFF Regulator The LP2952 and LP2953 retain all the desirable characteristics of the LP2951, but offer increased output current, additional features, and an improved shutdown function. The automatic output discharge pulls the output down quickly when the shutdown is activated. The error flag goes low if the output voltage drops out of regulation. Reverse battery-input protection is provided. The internal voltage reference is made available for external use, providing a low temperature coefficient (20 ppm/C) reference with very good line (0.03%) and load (0.04%) regulation. Device Information(1) PART NUMBER LP2952x LP2953x PACKAGE BODY SIZE (NOM) SOIC (16) 9.90 mm x 3.91 mm SOIC (16) 9.90 mm x 3.91 mm PDIP (16) 21.755 mm x 6.35 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Typical Application Schematic 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 4 4 4 5 5 5 6 9 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics: 3.3-V Versions ................. Electrical Characteristics: 5-V Versions .................... Electrical Characteristics: All Voltage Options .......... Typical Characteristics .............................................. Detailed Description ............................................ 14 7.1 Overview ................................................................. 14 7.2 Functional Block Diagrams ..................................... 14 7.3 Feature Description................................................. 15 7.4 Device Functional Mode ......................................... 16 8 Application and Implementation ........................ 17 8.1 Application Information............................................ 17 8.2 Typical Applications ................................................ 21 9 Power Supply Recommendations...................... 30 10 Layout................................................................... 31 10.1 Layout Guidelines ................................................. 31 10.2 Layout Example .................................................... 31 10.3 Power Dissipation: Heatsink Requirements (Industrial Temperature Range Devices) ................. 32 11 Device and Documentation Support ................. 34 11.1 11.2 11.3 11.4 Related Links ........................................................ Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 34 34 34 34 12 Mechanical, Packaging, and Orderable Information ........................................................... 34 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision E (December 2014) to Revision F Page * Deleted "Assured" .................................................................................................................................................................. 1 * Changed "Output Pulldown Crowbar" to "Automatic Output Discharge" ............................................................................... 1 * Changed "internal crowbar" to "automatic output discharge" ................................................................................................. 1 * Added word "input" after "battery" in Features and Description ............................................................................................. 1 * Changed pin names for IN and OUT to match TI nomenclature; fix typos ............................................................................ 1 * Changed max junc. temp from 125C to 150C .................................................................................................................... 4 * Changed wording of footnote 12 ........................................................................................................................................... 8 * Added second bullet for "LP2953 versions only" ................................................................................................................. 14 * Added Automatic Output Dischange subsection ................................................................................................................. 16 * Deleted sentence "To achieve the smallest form factor, the TO-92 package is selected.".................................................. 22 * Changed "With an efficiency of 83.3% and a 250-mA maximum load, the internal power dissipation is 250 mW, which corresponds to a 19.2C junction temperature rise for the SOIC package." to "With a VIN - VOUT differential of 1 V and a maximum load current of 250 mA the internal junction temperature (TJ) of the SOIC package will rise 19.2 above the ambient temperature."................................................................................................................................ 22 * Deleted "Thermal Resistance for Various Copper Heatsinking Patterns" table ................................................................... 33 Changes from Revision D (September 2013) to Revision E * Page Added Pin Configuration and Functions section, ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section; updated Thermal Information values; deleted obsolete LP2953AM references .................................................................................. 1 Changes from Revision C (March 2005) to Revision D * 2 Page Changed layout of National Data Sheet to TI format ........................................................................................................... 30 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 5 Pin Configuration and Functions 16 Pins LP2952 SOIC (D) Package Top View 16 Pins LP2953 SOIC (D) Package Top View 16 Pins LP2953 PDIP (NBG) Package Top View Pin Functions LP2952-N PIN NAME SOIC(D) I/O DESCRIPTION ERROR 6 O Error signal output FEEDBACK 14 I Error amplifier noninverting input 1, 8, 9, 16 - Ground GROUND IN 15 I Regulator power input NC 2, 7, 10, 11 - NC OUT 3 O Regulated output voltage REFERENCE 12 O Internal reference voltage output SENSE 4 I Feedback voltage sense input SHUTDOWN 5 I Shutdown input VTAP 13 I Internal resistor divider input Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 3 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com Pin Functions LP2953 PIN NAME I/O DESCRIPTION SOIC(D) PDIP(NBG) COMPIN 10 15 I Auxiliary comparator input COMPOUT 11 14 O Auxiliary comparator output ERROR 6 10 O Error signal output FEEDBACK 14 2 I Error amplifier noninverting input 1, 8, 9, 16 4, 5, 12, 13 - Ground IN 15 3 I Regulator power input NC GROUND 2, 7 7, 11 - NC OUT 3 6 O Regulated output voltage REFERENCE 12 16 O Internal reference voltage output SENSE 4 8 I Feedback voltage sense input SHUTDOWN 5 9 I Shutdown input VTAP 13 1 I Internal resistor divider input 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) MIN Power dissipation (2) MAX UNIT Internally Limited -20 Input supply voltage 30 V -0.3 5 V -0.3 30 V SHUTDOWN input voltage (4) -0.3 30 V (4) -0.3 (3) Comparator input voltage (4) FEEDBACK input voltage Comparator output voltage Maximum junction temperature -65 Storage temperature, Tstg (1) (2) (3) (4) 30 V 150 C 150 C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal resistance, RJA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using the equation for P(MAX): P(MAX) = (TJ(MAX) - TA) / RJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. See Power Supply Recommendations for additional information on heatsinking and thermal resistance. When used in dual-supply systems where the regulator load is returned to a negative supply, the output voltage must be diode-clamped to ground. May exceed the input supply voltage. 6.2 ESD Ratings VALUE V(ESD) (1) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins (1) 2000 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) Operating junction temperature Input supply voltage 4 Submit Documentation Feedback MIN MAX UNIT -40 125 C 2.3 30 V Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 6.4 Thermal Information LP2952, LP2953 LP2953 SOIC (D) PDIP (NBG) THERMAL METRIC (1) UNIT 16 PINS RJA Junction-to-ambient thermal resistance 76.9 42.1 RJC(top) Junction-to-case (top) thermal resistance 37.4 28.1 RJB Junction-to-board thermal resistance 34.6 22.2 JT Junction-to-top characterization parameter 7.3 12.0 JB Junction-to-board characterization parameter 34.3 22.1 (1) C/W For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953. 6.5 Electrical Characteristics: 3.3-V Versions Limits are assured by production testing or correlation techniques using standard Statistical Quality Control (SQC) methods. Unless otherwise specified: MIN (minimum) and MAX (maximum) specifications in apply over the full Operating Temperature Range and TYP (typical) values apply at TJ = 25C, VIN = VOUT(NOM) + 1 V, IOUT = 1 mA, COUT = 2.2 F for 5-V parts and 4.7 F for 3.3-V parts. FEEDBACK pin is tied to VTAP pin, OUT pin is tied to SENSE pin. PARAMETER TEST CONDITIONS LP2952AI-3.3, LP2953AI-3.3 TJ = 25C VOUT Output voltage 1 mA IOUT 250 mA LP2952I-3.3, LP2953I-3.3 MIN TYP MAX MIN TYP MAX 3.284 3.3 3.317 3.267 3.3 3.333 3.260 3.3 3.340 3.234 3.3 3.366 3.254 3.3 3.346 3.221 3.3 3.379 UNIT V 6.6 Electrical Characteristics: 5-V Versions Limits are assured by production testing or correlation techniques using standard Statistical Quality Control (SQC) methods. Unless otherwise specified, MIN (minimum) and MAX (maximum) specifications in apply over the full Operating Temperature Range and TYP (typical) values apply at TJ = 25C, VIN = VOUT(NOM) + 1 V, IOUT = 1 mA, COUT = 2.2 F for 5-V parts and 4.7 F for 3.3-V parts. FEEDBACK pin is tied to VTAP pin, OUT pin is tied to SENSE pin. PARAMETER TEST CONDITIONS TJ = 25C VOUT Output voltage 1 mA IOUT 250 mA Copyright (c) 2004-2015, Texas Instruments Incorporated LP2952AI, LP2953AI LP2952I, LP2953I MIN TYP MAX MIN TYP MAX 4.975 5 5.025 4.95 5 5.05 4.94 5 5.06 4.9 5 5.1 4.93 5 5.07 4.88 5 5.12 Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A UNIT V 5 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com 6.7 Electrical Characteristics: All Voltage Options Limits are assured by production testing or correlation techniques using standard Statistical Quality Control (SQC) methods. Unless otherwise specified, MIN (minimum) and MAX (maximum) specifications in apply over the full Operating Temperature Range and TYP (typical) values apply at TJ = 25C, VIN = VOUT(NOM) + 1 V, IOUT = 1 mA, COUT = 2.2 F for 5-V parts and 4.7 F for 3.3-V parts. FEEDBACK pin is tied to VTAP pin, OUT pin is tied to SENSE pin. PARAMETER TEST CONDITIONS LP2952AI, LP2953AI, LP2952AI-3.3, LP2953AI-3.3 (1) MIN LP2952I, LP2953I, LP2952I-3.3, LP2953I-3.3 MIN TYP UNIT TYP MAX MAX 20 100 20 TJ = 25C VIN = VOUT(NOM) + 1 V to 30 V 0.03% 0.1% 0.03% 0.2% VIN = VOUT(NOM) + 1 V to 30 V 0.03% 0.2% 0.03% 0.4% TJ = 25C IOUT = 1 mA to 250 mA 0.04% 0.16% 0.04% 0.20% IOUT = 0.1 mA to 1 mA REGULATOR uVOUT uT Output voltage temperature coefficient uVOUT uV Output voltage line regulation uVOUT uV Output voltage load regulation (3) VIN - VOUT IGND Dropout voltage (4) Ground pin current (5) See (2) 0.04% 0.20% 0.04% 0.30% TJ = 25C, IOUT = 1 mA 60 100 60 100 IOUT = 1 mA 60 150 60 150 IOUT = 50 mA 240 300 240 300 IOUT = 50 mA 240 420 240 420 TJ = 25C, IOUT = 100 mA 310 400 310 400 IOUT = 100 mA 310 520 310 520 TJ = 25C, IOUT = 250 mA 470 600 470 600 IOUT = 250 mA 470 800 470 800 TJ = 25C, IOUT = 1 mA 130 170 130 170 IOUT = 1 mA 130 200 130 200 TJ = 25C, IOUT = 50 mA 1.1 2 1.1 2 IOUT = 50 mA 1.1 2.5 1.1 2.5 TJ = 25C, IOUT = 100 mA 4.5 6 4.5 6 IOUT = 100 mA 4.5 8 4.5 8 TJ = 25C, IOUT = 250 mA 21 28 21 28 IOUT = 250 mA IGND Ground pin current at dropout IGND Ground pin current at shutdown (5) ILIMIT Current limit uVOUT uPD Thermal regulation (1) (2) (3) (4) (5) (6) 6 150 ppm/C 21 33 21 33 VIN = VOUT(NOM) - 0.5 V 165 210 165 210 IOUT = 100 A -40C TJ 125C 165 240 165 240 TJ = 25C, VSHUTDOWN 1.1 V 105 140 105 140 TJ = 25C, VOUT = 0 380 500 380 500 VOUT = 0 380 530 380 530 TJ = 25C; see (6) 0.05 0.2 0.05 0.2 mV A mA A A mA %/W Drive SHUTDOWN pin with TTL or CMOS low level to shut off regulator, high level to turn on regulator. Output or reference voltage temperature coefficient is defined as the worst-case voltage change divided by the total temperature range. Load regulation is measured at constant junction temperature using low duty-cycle pulse testing. Two separate tests are performed, one for the range of IOUT = 100 A to 1 mA and one for the range of IOUT =1 mA to 250 mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification. Dropout voltage is defined as the input-to-output differential at which the output voltage drops 100 mV below the value measured with a 1-V differential. At very low values of programmed output voltage, the input voltage minimum of 2 V (2.3 V over temperature) must be observed. Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the ground pin current, output load current, and current through the external resistive divider (if used). Thermal regulation is the change in output voltage at a time t after a change in power dissipation, excluding load or line regulation effects. Specifications are for a 200-mA load pulse at VIN = VOUT(NOM) + 15 V (3-W pulse) for t = 10 ms. Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 Electrical Characteristics: All Voltage Options (continued) Limits are assured by production testing or correlation techniques using standard Statistical Quality Control (SQC) methods. Unless otherwise specified, MIN (minimum) and MAX (maximum) specifications in apply over the full Operating Temperature Range and TYP (typical) values apply at TJ = 25C, VIN = VOUT(NOM) + 1 V, IOUT = 1 mA, COUT = 2.2 F for 5-V parts and 4.7 F for 3.3-V parts. FEEDBACK pin is tied to VTAP pin, OUT pin is tied to SENSE pin. PARAMETER LP2952AI, LP2953AI, LP2952AI-3.3, LP2953AI-3.3 (1) TEST CONDITIONS MIN en VREF TYP LP2952I, LP2953I, LP2952I-3.3, LP2953I-3.3 MAX MIN TYP Output noise voltage (10 Hz to 100 kHz) IOUT = 100 mA COUT = 4.7 F 400 400 COUT = 33 F 260 260 Reference voltage TJ = 25C, see (8) Reference voltage line regulation VIN = 2.5 V to VOUT + 1 V Reference voltage load regulation Reference voltage temperature coefficient COUT = 33 F (7) 80 1.215 (8) see , 1.23 1.205 UNIT MAX V RMS 80 1.245 1.205 1.255 1.19 1.23 1.255 0.03% 0.1% 0.03% 0.2% 0.03% 0.2% 0.03% 0.4% TJ = 25C, IREF = 0 to 200 A 0.25% 0.4% 0.25% 0.8% IREF = 0 to 200 A 0.25% 0.6% 0.25% 1.0% VIN = VOUT(NOM)+ 1 V to 30 V (9) See (2), -40C TJ 125C 20 TJ = 25C 20 40 20 40 20 60 20 60 IB(FB) Feedback pin bias current IO(SINK) TJ = 25C; see Output off pulldown current See (10) (10) 20 30 30 20 20 V 1.27 ppm/C nA mA DROPOUT DETECTION COMPARATOR Output high leakage IOH Output low voltage VOL TJ = 25C, VOH = 30 V 0.01 1 0.01 1 VOH = 30 V 0.01 2 0.01 2 TJ = 25C, VIN = VOUT(NOM) - 0.5 V IOUT(COMP) = 400 A 150 250 150 250 VIN = VOUT(NOM) - 0.5 V IOUT(COMP) = 400 A 150 400 -80 -60 -35 -95 -60 -25 (11) mV 150 400 -80 -60 -35 -95 -60 -25 VTHR(MAX) Upper threshold voltage TJ = 25C, see VTHR(MIN) Lower threshold voltage TJ = 25C, see (11) -110 -85 -55 -110 -85 -55 See (11) -160 -85 -40 -160 -85 -40 HYST Hysteresis See (11) (7) (8) (9) (10) (11) See (11) A 15 15 mV mV mV Connect a 0.1-F capacitor from the OUT pin to the FEEDBACK pin. VREF VOUT (VIN - 1 V), 2.3 V VIN 30 V, 100 A IOUT 250 mA. Two separate tests are performed, one covering 2.5 V VIN VOUT(NOM)) + 1 V and the other test for VOUT(NOM) + 1 V VIN 30 V. VSHUTDOWN 1.1 V, VOUT = VOUT(NOM) Comparator thresholds are expressed in terms of a voltage differential at the FEEDBACK pin below the nominal reference voltage measured at VIN = VOUT(NOM) + 1 V. To express these thresholds in terms of output voltage change, multiply by the error amplifier gain, which is VOUT / VREF = (R1 + R2) / R2 (see Figure 31). Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 7 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com Electrical Characteristics: All Voltage Options (continued) Limits are assured by production testing or correlation techniques using standard Statistical Quality Control (SQC) methods. Unless otherwise specified, MIN (minimum) and MAX (maximum) specifications in apply over the full Operating Temperature Range and TYP (typical) values apply at TJ = 25C, VIN = VOUT(NOM) + 1 V, IOUT = 1 mA, COUT = 2.2 F for 5-V parts and 4.7 F for 3.3-V parts. FEEDBACK pin is tied to VTAP pin, OUT pin is tied to SENSE pin. PARAMETER TEST CONDITIONS LP2952AI, LP2953AI, LP2952AI-3.3, LP2953AI-3.3 (1) LP2952I, LP2953I, LP2952I-3.3, LP2953I-3.3 UNIT MIN TYP MAX MIN TYP MAX -7.5 3 7.5 -7.5 3 7.5 10 -10 SHUTDOWN INPUT (12) VOS HYST IB Input offset voltage TJ = 25C (Referred to VREF) -10 Hysteresis Input bias current 6 TJ = 25C VIN(SD) = 0 V to 5 V -30 VIN(SD) = 0 V to 5 V -50 10 6 30 -30 50 -50 mV 10 10 mV -30 nA 50 AUXILIARY COMPARATOR (LP2953 Only) VOS HYST IB Input offset voltage TJ = 25C (Referred to VREF) -7.5 3 7.5 -7.5 3 7.5 (Referred to VREF) -10 3 10 -10 3 10 Hysteresis Input bias current 6 6 mV mV TJ = 25C, VIN(COMP) = 0 V to 5 V -30 10 30 -30 10 30 VIN(COMP) = 0 V to 5 V -50 10 50 -50 10 50 IOH Output high leakage TJ = 25C, VOH = 30 V 0.01 1 0.01 1 VIN(COMP) = 1.3 V 0.01 2 0.01 2 VOL Output low voltage TJ = 25C, VIN(COMP) = 1.1 V 150 250 150 250 IOUT(COMP) = 400 A 150 400 150 400 nA A mV (12) Drive SHUTDOWN pin with TTL or CMOS-low level to shut regulator OFF, high level to turn regulator ON. 8 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 6.8 Typical Characteristics Unless otherwise specified: VIN = 6 V, IOUT = 1 mA, COUT = 2.2 F, VSD = 3 V, TA = 25C, VOUT = 5 V. Figure 1. Quiescent Current Figure 2. Quiescent Current Figure 3. Ground Pin Current vs Load Figure 4. Ground Pin Current Figure 5. Ground Pin Current Figure 6. Output Noise Voltage Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 9 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com Typical Characteristics (continued) Unless otherwise specified: VIN = 6 V, IOUT = 1 mA, COUT = 2.2 F, VSD = 3 V, TA = 25C, VOUT = 5 V. 10 Figure 7. Ripple Rejection Figure 8. Ripple Rejection Figure 9. Ripple Rejection Figure 10. Line Transient Response Figure 11. Line Transient Response Figure 12. Output Impedance Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 Typical Characteristics (continued) Unless otherwise specified: VIN = 6 V, IOUT = 1 mA, COUT = 2.2 F, VSD = 3 V, TA = 25C, VOUT = 5 V. Figure 13. Load Transient Response Figure 14. Load Transient Response Figure 15. Dropout Characteristics Figure 16. Enable Transient Figure 17. Enable Transient Figure 18. Short-Circuit Output Current and Maximum Output Current Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 11 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com Typical Characteristics (continued) Unless otherwise specified: VIN = 6 V, IOUT = 1 mA, COUT = 2.2 F, VSD = 3 V, TA = 25C, VOUT = 5 V. 12 Figure 19. Feedback Bias Current Figure 20. FEEDBACK Pin Current Figure 21. Error Output Figure 22. Comparator Sink Current Figure 23. Divider Resistance Figure 24. Dropout Detection Comparator Threshold Voltages Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 Typical Characteristics (continued) Unless otherwise specified: VIN = 6 V, IOUT = 1 mA, COUT = 2.2 F, VSD = 3 V, TA = 25C, VOUT = 5 V. Figure 25. Thermal Regulation Figure 26. Minimum Operating Voltage Figure 27. Dropout Voltage Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 13 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com 7 Detailed Description 7.1 Overview The LP2952 and LP2953 are very high accuracy micropower voltage regulators with low quiescent current (130 A, typical) and low dropout voltage (typically 60 mV at light loads and 490 mV at 250 mA). They are ideally suited for use in battery-powered systems. The LP2952 and LP2953 block diagram contains several features, including: * Very high accuracy 1.23-V reference. * Internal protection circuitry, such as thermal foldback current limit, thermal shutdown protection, and reverse battery-input protection. * Fixed 5-V and 3.3-V versions. * Error flag output which may be used for a power-on reset. * Shutdown input, allowing turn off the regulator when the SHUTDOWN pin is pulled low. LP2953 versions only: * An auxiliary comparator is designed for customer special purpose when shutdown is activated, this is a CMOS- or TTL-compatible output level. * Automatic output discharge when the SHUTDOWN pin is pulled low. 7.2 Functional Block Diagrams Figure 28. LP2952 Block Diagram 14 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 Functional Block Diagrams (continued) Figure 29. LP2953 Block Diagram 7.3 Feature Description 7.3.1 Fixed Voltage Options and Programmable Voltage Version The LP2952 and LP2953 provide 2 fixed output options: 3.3 V and 5 V. To meet different requirements for the application, they can also be used as programmable voltage regulators with external resistor networks; see Application Information for more details. 7.3.2 High-Accuracy Output Voltage With special and careful design to minimize all contributions to the output voltage error, the LP2952 and LP2953 distinguished themselves as very high output voltage accuracy micropower LDO. This includes a tight initial tolerance (0.5% typical), extremely good load and line regulation, and a very low output voltage temperature coefficient, making the part an ideal a low-power voltage reference. 7.3.3 Error Detection Comparator Output The LP2952 and LP2953 will generate a logic low output when the output falls out of regulation by more than approximately 5%. See Application Information for more details. 7.3.4 Auxiliary Comparator An auxiliary comparator is designed for customer special purpose when shutdown is activated. This block is still active and can be used to generate fault detection, low input line detection signal for system controllers. The comparator output level is CMOS- or TTL-compatible. See Application Information for more details. Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 15 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com Feature Description (continued) 7.3.5 Short-Circuit Protection (Current Limit) The internal current limit circuit is used to protect the LDO against high-load current faults or shorting events. The LDO is not designed to operate in a steady-state current limit. During a current-limit event, the LDO sources constant current. Therefore, the output voltage falls when load impedance decreases. Note also that if a current limit occurs and the resulting output voltage is low, excessive power may be dissipated across the LDO resulting in a thermal shutdown of the output. A thermal foldback feature limits the short-circuit current to protect the regulator from damage under all load conditions. If the OUT pin is forced below 0 V before SHUTDOWN goes high and the load current required exceeds the thermal foldback current limit, the device may not start up correctly. 7.3.6 Thermal Protection The device contains a thermal shutdown protection circuit to turn off the output current when excessive heat is dissipated in the LDO. The thermal time-constant of the semiconductor die is fairly short, and thus the output cycles on and off at a high rate when thermal shutdown is reached until the power dissipation is reduced. The internal protection circuitry of the device is designed to protect against thermal overload conditions. The circuitry is not intended to replace a proper heatsink. Continuously running the device into thermal shutdown degrades its reliability. 7.3.7 Automatic Output Discharge Both LP2952 and LP2953 employ an internal 50-mA (typical) pulldown to discharge the output when the SHUTDOWN pin is low and the output is disabled. 7.4 Device Functional Mode 7.4.1 Shutdown Mode When pulling the SHUTDOWN pin to low level, the LP2952 and LP2953 will enter shutdown mode, and a very low quiescent current is consumed. This function is designed for applications which needs a shutdown mode to effectively enhance battery life cycle. When the SHUTDOWN pin is low the automatic output discharge circuity will be active. See Application Information for more details. 7.4.2 Operation with 30 V VIN > VOUT(TARGET) + 1 V The device operate if the input voltage is equal to, or exceeds, VOUT(TARGET) + 1 V, and SHUTDOWN is pulled to high level. At input voltages below the minimum VIN requirement, the devices do not operate correctly and output voltage may not reach target value. 16 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI's customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information Figure 30. Schematic Diagram Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 17 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com Application Information (continued) 8.1.1 External Capacitors A 2.2-F (or greater) capacitor is required between the OUT pin and ground to assure stability when the output is set to 5 V. Without this capacitor, the device will oscillate. Most types of tantalum or aluminum electrolytic capacitors will work here. Film types will work, but are more expensive. Many aluminum electrolytic capacitors contain electrolytes which freeze at -30C, which requires the use of solid tantalum capacitors below -25C. The important parameters of the capacitor are an equivalent series resistance (ESR) of about 5 or less and a resonant frequency above 500 kHz (the ESR may increase by a factor of 20 or 30 as the temperature is reduced from 25C to -30C). The value of this capacitor may be increased without limit. At lower values of output current, less output capacitance is required for stability. The capacitor can be reduced to 0.68 F for currents below 10 mA or 0.22 F for currents below 1 mA. Programming the output for voltages below 5 V runs the error amplifier at lower gains requiring more output capacitance for stability. At 3.3-V output, a minimum of 4.7 F is required. For the worst-case condition of 1.23-V output and 250 mA of load current, a 6.8-F (or larger) capacitor should be used. A 1-F capacitor should be placed from the IN pin to ground if there is more than 10 inches of wire between the IN pin and the ac filter capacitor or if a battery input is used. Stray capacitance to the FEEDBACK pin can cause instability. This problem is most likely to appear when using high-value external resistors to set the output voltage. Adding a 100-pF capacitor between the OUT and FEEDBACK pins and increasing the output capacitance to 6.8 F (or greater) will cure the problem. 8.1.2 Minimum Load When setting the output voltage using an external resistive divider, a minimum current of 1 A is recommended through the resistors to provide a minimum load. It should be noted that a minimum load current is specified in several of the Electrical Characteristics: All Voltage Options test conditions, so this value must be used to obtain correlation on these tested limits. 8.1.3 Programming the Output Voltage The regulator may be pin-strapped for 5-V operation using its internal resistive divider by tying the OUTPUT and SENSE pins together and also tying the FEEDBACK and VTAP pins together. Alternatively, it may be programmed for any voltage between the 1.23-V reference and the 30-V maximum rating using an external pair of resistors (see Figure 31). The complete equation for the output voltage is: where * VREF is the 1.23-V reference and IFB is the FEEDBACK pin bias current (-20 nA, typical). (1) The minimum recommended load current of 1 A sets an upper limit of 1.2 M on the value of R2 in cases where the regulator must work with no load (see Minimum Load). IFB will produce a typical 2% error in VOUT which can be eliminated at room temperature by trimming R1. For better accuracy, choosing R2 = 100 k will reduce this error to 0.17% while increasing the resistor program current to 12 A. Because the typical quiescent current is 120 A, this added current is negligible. 18 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 Application Information (continued) * See Power Supply Recommendations ** Drive with TTL-low to shutdown Figure 31. Adjustable Regulator 8.1.4 Dropout Voltage The dropout voltage of the regulator is defined as the minimum input-to-output voltage differential required for the output voltage to stay within 100 mV of the output voltage measured with a 1-V differential. The dropout voltage is independent of the programmed output voltage. 8.1.5 Dropout Detection Comparator This comparator produces a logic low whenever the output falls out of regulation by more than about 5%. This value results from the comparator built-in offset of 60 mV divided by the 1.23-V reference (see Functional Block Diagrams). The 5% low trip level remains constant regardless of the programmed output voltage. An out-ofregulation condition can result from low input voltage, current limiting, or thermal limiting. Figure 32 gives a timing diagram showing the relationship between the output voltage, the ERROR output, and input voltage as the input voltage is ramped up and down to a regulator programmed for 5-V output. The ERROR signal becomes low at about 1.3-V input. It goes high at about 5-V input, where the output equals 4.75 V. Because the dropout voltage is load dependent, the input voltage trip points will vary with load current. The output voltage trip point does not vary. The comparator has an open-collector output which requires an external pullup resistor. This resistor may be connected to the regulator output or some other supply voltage. Using the regulator output prevents an invalid high on the comparator output that occurs if it is pulled up to an external voltage while the regulator input voltage is reduced below 1.3 V. In selecting a value for the pullup resistor, note that while the output can sink 400 A, this current adds to battery drain. Suggested values range from 100 k to 1 M. This resistor is not required if the output is unused. When VIN 1.3 V, the ERROR pin becomes a high impedance, allowing the error flag voltage to rise to its pullup voltage. Using VOUT as the pullup voltage (rather than an external 5-V source) will keep the error flag voltage below 1.2 V (typical) in this condition. The user may wish to divide down the error flag voltage using equal-value resistors (10 k is suggested) to ensure a low-level logic signal during any fault condition, while still allowing a valid logic high level during normal operation. Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 19 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com Application Information (continued) * In shutdown mode, ERROR will go high if it has been pulled up to an external supply. To avoid this invalid response, pull up to regulator output. ** Exact value depends on dropout voltage. (See Power Supply Recommendations) Figure 32. ERROR Output Timing 8.1.6 Output Isolation The regulator output can be left connected to an active voltage source (such as a battery) with the regulator input power shut off, as long as the regulator ground pin is connected to ground. If the ground pin is left floating, damage to the regulator can occur if the output is pulled up by an external voltage source. If the regulator input power (VIN) is applied, and the SHUTDOWN pin is low, the automatic output discharge circuit will be active, and any voltage source applied to the output will be discharged to ground. 8.1.7 Reducing Output Noise In reference applications it may be advantageous to reduce the ac noise present on the output. One method is to reduce regulator bandwidth by increasing output capacitance. This is relatively inefficient, because large increases in capacitance are required to get significant improvement. Noise can be reduced more effectively by a bypass capacitor placed across R1 (see Figure 31). The formula for selecting the capacitor to be used is: (2) This gives a value of about 0.1 F. When this is used, the output capacitor must be 6.8 F (or greater) to maintain stability. The 0.1-F capacitor reduces the high-frequency gain of the circuit to unity, lowering the output noise from 260 V to 80 V using a 10-Hz to 100-kHz bandwidth. Also, noise is no longer proportional to the output voltage, so improvements are more pronounced at high output voltages. 20 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 Application Information (continued) 8.1.8 Auxiliary Comparator (LP2953 Only) The LP2953 contains an auxiliary comparator whose inverting input is connected to the 1.23-V reference. The auxiliary comparator has an open-collector output whose electrical characteristics are similar to the dropout detection comparator. The noninverting input and output are brought out for external connections. 8.1.9 SHUTDOWN Input A logic-level signal will shut off the regulator output when a low (< 1.2 V) is applied to the SHUTDOWN input. To prevent possible mis-operation, the SHUTDOWN input must be actively terminated. If the input is driven from open-collector logic, a pullup resistor (20 k to 100 k is recommended) should be connected from the SHUTDOWN input to the regulator input. If the SHUTDOWN input is driven from a source that actively pulls high and low (like an op-amp), the pullup resistor is not required, but may be used. If the shutdown function is not to be used, the cost of the pullup resistor can be saved by simply tying the SHUTDOWN input directly to the regulator input. NOTE Because the Absolute Maximum Ratings state that the SHUTDOWN input can not go more than 0.3 V below ground, the reverse battery-input protection feature which protects the regulator input is sacrificed if the SHUTDOWN input is tied directly to the regulator input. If reverse-battery input protection is required in an application, the pullup resistor between the SHUTDOWN input and the regulator input must be used. 8.2 Typical Applications 8.2.1 Basic 5-V Regulator Figure 33. Basic 5-V Regulator Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 21 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com Typical Applications (continued) 8.2.1.1 Design Requirements For this design example, use the parameters listed in Table 1 as the input parameters. Table 1. Design Parameters DESIGN PARAMETER DESIGN REQUIREMENT Input voltage 6 V, 10%, provided by the DC-DC converter switching at 1 MHz Output voltage 5 V, 1% Output current 250 mA (maximum), 1 mA (minimum) RMS noise, 10 Hz to 100 kHz 1 mV typical PSRR at 1 kHz 50 dB typical 8.2.1.2 Detailed Design Procedure At 150-mA loading, the dropout of the LP2952 and LP2953 has 600-mV maximum dropout over temperature -- thus, a 1500-mV headroom is sufficient for operation over both input and output voltage accuracy. The efficiency of the LP2952 and LP2953 in this configuration is VOUT / VIN = 83.3%. Input and output capacitors are selected in accordance with the External Capacitors section. Ceramic capacitances of 1 F for the input and one 2.2-F capacitor for the output are selected. With an efficiency of 83.3% and a 250-mA maximum load, the internal power dissipation is 250 mW, which corresponds to a 19.2C junction temperature rise for the SOIC package. With a VIN - VOUT differential of 1 V and a maximum load current of 250 mA the internal junction temperature (TJ) of the SOIC package will rise 19.2C above the ambient temperature. With an 85C maximum ambient temperature, the junction temperature is at 104.2C. To minimize noise, a bypass capacitor of 100 pF is selected between OUT and FEEDBACK pins. 8.2.1.3 Application Curves Figure 34. Line Transient Response 22 Submit Documentation Feedback Figure 35. Load Transient Response Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 8.2.2 5-V Current Limiter with Load Fault Indicator Figure 36 is the example circuit for 5-V current limiter with load fault indicator, it has the following features: * Output voltage equals +VIN minimum dropout voltage, which varies with output current. Current limits at a maximum of 380 mA (typical). * Select R1 so that the comparator input voltage is 1.23 V at the output voltage which corresponds to the desired fault current value. Figure 36. 5-V Current Limiter With Load Fault Indicator Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 23 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com 8.2.3 Low Temperature Coefficient Current Sink The LP2952 or LP2953 can be used as a low drift current source as Figure 37 shows. By connecting VOUT to FEEDBACK, VOUT will be regulated at 1.235 V, and current consumption at R is IOUT = 1.23/R. Figure 37. Low Temperature Coefficient Current Sink 24 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 8.2.4 5-V Regulator With Error Flags for Low Battery and Out of Regulation Figure 38 is the example circuit for 5-V regulator with error flags for low battery and out of regulation, it has the following features: * Connect to logic or microprocessor control inputs. * LOW BATT flag warns the user that the battery has discharged down to about 5.8 V, giving the user time to recharge the battery or power down some hardware with high power requirements. The output is still in regulation at this time. * OUT OF REGULATION flag indicates when the battery is almost completely discharged, and can be used to initiate a power-down sequence. Figure 38. 5-V Regulator With Error Flags for Low Battery and Out of Regulation Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 25 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com 8.2.5 5-V Battery Powered Supply With Backup and Low Battery Flag Figure 39 is the example circuit for 5-V battery powered supply with backup and low battery flag, it has the following features: * The circuit switches to the NI-CAD backup battery when the main battery voltage drops below about 5.6 V and returns to the main battery when its voltage is recharged to about 6 V. * The 5-V MAIN output powers circuitry which requires no backup, and the 5-V MEMORY output powers critical circuitry which cannot be allowed to lose power. * The BATTERY LOW flag goes low whenever the circuit switches to the NI-CAD backup battery. Figure 39. 5-V Battery Powered Supply With Backup and Low Battery Flag 26 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 8.2.6 5-V Regulator With Timed Power-On Reset Figure 40 is the circuit designed to generate a adjustable power on reset signal. Adjusting RT and CT values causes a certain delay time as Figure 41 shows. Figure 40. 5-V Regulator With Timed Power-On Reset * RT = 1 M, CT = 0.1 F Figure 41. Timing Diagram for Timed Power-On Reset Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 27 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com 8.2.7 5-V Regulator With Snap-ON and Snap-OFF Features and Hysteresis Figure 42 is the circuit designed to generate 5-V regulator with snap-ON and snap-OFF features and hysteresis. The output turns on at VIN = 5.87 V and turns off at VIN = 5.64 V. * Turns on at VIN = 5.87 V Turns off at VIN = 5.64 V (for component values shown) Figure 42. 5-V Regulator With Snap-ON and Snap-OFF Features and Hysteresis 28 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 8.2.8 5-V Regulator With Error Flags for Low Battery and Out of Regulation With Snap-ON or Snap-OFF Output Figure 43 is the circuit as 5-V regulator with error flags for low battery and out of regulation with Snap-ON/SnapOFF output. It has the following features: * Connect to logic or microprocessor control inputs. * LOW BATT flag warns the user that the battery has discharged down to about 5.8 V, giving the user time to recharge the battery or shutdown hardware with high power requirements. The output is still in regulation at this time. * OUT OF REGULATION flag goes low if the output goes below about 4.7 V, which could occur from a load fault. * OUTPUT has Snap-ON or Snap-OFF feature. Regulator snaps ON at about 5.7-V input, and OFF at about 5.6 V. Figure 43. 5-V Regulator With Error Flags for Low Battery and Out of Regulation With Snap-ON or SnapOFF Output Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 29 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com 8.2.9 5-V Regulator With Timed Power-On Reset, Snap-ON and Snap-OFF Features, and Hysteresis Figure 44 is the circuit designed for 5-V regulator with timed power-on reset, Snap-ON and Snap-OFF features, and hysteresis. Its timing diagram shows as Figure 45. Figure 44. 5-V Regulator With Timed Power-On Reset, Snap-ON or Snap-OFF Feature, and Hysteresis td = (0.28), RC = 28 ms for components shown. Figure 45. Timing Diagram 9 Power Supply Recommendations The LP2952 and LP2953 is designed to operate from an input voltage supply range between 2.3 V and 30 V. The input voltage range provides adequate headroom in order for the device to have a regulated output, normally VIN should be 1 V higher than output voltage to provide a sufficient headroom. This input supply must be well regulated. If the input supply is noisy, additional input capacitors with low ESR can help improve the output noise performance. Maximum VIN should never be higher than 30 V. Input voltage beyond 30 V may trigger EOS and cause permanent damage to the device. 30 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 10 Layout 10.1 Layout Guidelines For best overall performance, place all circuit components on the same side of the circuit board and as near as practical to the respective LDO pin connections. Place ground return connections to the input and output capacitors, and to the LDO ground pin as close to each other as possible, connected by a wide, component-side, copper surface. The use of vias and long traces to create LDO circuit connections is strongly discouraged and negatively affects system performance. This grounding and layout scheme minimizes inductive parasitics, and thereby reduces load-current transients, minimizes noise, and increases circuit stability. A ground reference plane is also recommended and is either embedded in the PCB itself or located on the bottom side of the PCB opposite the components. This reference plane serves to assure accuracy of the output voltage, shield noise, and behaves similar to a thermal plane to spread (or sink) heat from the LDO device. In most applications, this ground plane is necessary to meet thermal requirements. 10.2 Layout Example GROUND GND Input Capacitor NC IN OUT FEEDBACK SENSE VTAP VIN Output Capacitor VOUT Ground Error Pullup Resistor Vout SHUTDOWN REFERENCE ERROR NC NC NC GROUND GROUND Figure 46. Layout Schematic Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 31 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com 10.3 Power Dissipation: Heatsink Requirements (Industrial Temperature Range Devices) The maximum allowable power dissipation for the LP2952 or LP2953 is limited by the maximum operating junction temperature (125C) and the external factors that determine how quickly heat flows away from the part: the ambient temperature and the junction-to-ambient thermal resistance (RJA) for the specific application. The industrial temperature range (-40C TJ 125C) parts are manufactured in PDIP and surface-mount packages which contain a copper lead frame that allows heat to be effectively conducted away from the die, through the ground pins of the IC, and into the copper of the PC board. Details on heatsinking using PC board copper are covered later. Figure 47. Power Dissipation vs Ambient Temperature for RJA = 95C/W To determine if a heatsink is required, the maximum power dissipated by the regulator, P(MAX), must be calculated. It is important to remember that if the regulator is powered from a transformer connected to the AC line, the maximum specified AC input voltage must be used (because this produces the maximum DC input voltage to the regulator). Figure 48 shows the voltages and currents which are present in the circuit. The formula for calculating the power dissipated in the regulator is also shown in Figure 48: Figure 48. PTOTAL = (VIN - VOUT) IOUT + (VIN) IG Current/Voltage Diagram The next parameter which must be calculated is the maximum allowable temperature rise, TR(MAX). This is calculated by using the formula: TR(MAX) = TJ(MAX) - TA(MAX) = RJA x P(MAX) where: * * TJ(MAX) is the maximum allowable junction temperature TA(MAX) is the maximum ambient temperature (3) Using the calculated values for TR(MAX) and P(MAX), the required value for junction-to-ambient thermal resistance, RJA, can now be found. 32 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A LP2952-N, LP2952A, LP2953, LP2953A www.ti.com SNVS095F - MAY 2004 - REVISED MARCH 2015 Power Dissipation: Heatsink Requirements (Industrial Temperature Range Devices) (continued) The heatsink is made using the PC board copper. The heat is conducted from the die, through the lead frame (inside the part), and out the pins which are soldered to the PC board. The pins used for heat conduction are given in Table 2. Table 2. Heat Conducting Pins PART LP2953IN, LP2953AIN LP2953IN-3.3, LP2953AIN-3.3 PACKAGE PINS 16-pin PDIP 4, 5, 12, 13 16-pin surface mount (SOIC) 1, 8, 9, 16 LP2952IM, LP2952AIM LP2952IM-3.3, LP2952AIM-3.3 LP2953IM, LP2953AIM LP2953IM-3.3, LP2953AIM-3.3 Figure 49 shows copper patterns which may be used to dissipate heat from the LP2952 and LP2953. * For best results, use L = 2H. ** 14-Pin PDIP is similar, see Table 2 for pins designated for heatsinking. Figure 49. Copper Heatsink Patterns Copyright (c) 2004-2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LP2952-N LP2952A LP2953 LP2953A 33 LP2952-N, LP2952A, LP2953, LP2953A SNVS095F - MAY 2004 - REVISED MARCH 2015 www.ti.com 11 Device and Documentation Support 11.1 Related Links Table 3 lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy. Table 3. Related Links PARTS PRODUCT FOLDER SAMPLE & BUY TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY LP2952-N Click here Click here Click here Click here Click here LP2952A Click here Click here Click here Click here Click here LP2953 Click here Click here Click here Click here Click here LP2953A Click here Click here Click here Click here Click here 11.2 Trademarks All trademarks are the property of their respective owners. 11.3 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 11.4 Glossary SLYZ022 -- TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 34 Submit Documentation Feedback Copyright (c) 2004-2015, Texas Instruments Incorporated Product Folder Links: LP2952-N LP2952A LP2953 LP2953A PACKAGE OPTION ADDENDUM www.ti.com 30-Jul-2018 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (C) Device Marking (4/5) LP2952AIM NRND SOIC D 16 48 TBD Call TI Call TI -40 to 125 LP2952AIM LP2952AIM/NOPB ACTIVE SOIC D 16 48 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LP2952AIM LP2952AIMX/NOPB ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LP2952AIM LP2952IM NRND SOIC D 16 48 TBD Call TI Call TI -40 to 125 LP2952IM LP2952IM/NOPB ACTIVE SOIC D 16 48 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LP2952IM LP2952IMX/NOPB ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LP2952IM LP2953AIM/NOPB ACTIVE SOIC D 16 48 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LP2953AIM LP2953AIMX/NOPB ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LP2953AIM LP2953IM NRND SOIC D 16 48 TBD Call TI Call TI -40 to 125 LP2953IM LP2953IM/NOPB ACTIVE SOIC D 16 48 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LP2953IM LP2953IMX/NOPB ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LP2953IM (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com (4) 30-Jul-2018 There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. 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Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 8-Oct-2016 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LP2952AIMX/NOPB SOIC D 16 2500 330.0 16.4 6.5 10.3 2.3 8.0 16.0 Q1 LP2952IMX/NOPB SOIC D 16 2500 330.0 16.4 6.5 10.3 2.3 8.0 16.0 Q1 LP2953AIMX/NOPB SOIC D 16 2500 330.0 16.4 6.5 10.3 2.3 8.0 16.0 Q1 LP2953IMX/NOPB SOIC D 16 2500 330.0 16.4 6.5 10.3 2.3 8.0 16.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 8-Oct-2016 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LP2952AIMX/NOPB SOIC D 16 2500 367.0 367.0 35.0 LP2952IMX/NOPB SOIC D 16 2500 367.0 367.0 35.0 LP2953AIMX/NOPB SOIC D 16 2500 367.0 367.0 35.0 LP2953IMX/NOPB SOIC D 16 2500 367.0 367.0 35.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated (TI) reserves the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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