ILOAD (A)
0.1 1.0 10
84
86
88
90
92
94
96
EFFICIENCY (%)
PVIN = 3.3V
PVIN
AVIN
EN
SS SGND PGND
SNS
SW
LM2852Y
CSS = 2.7 nF
CIN = 22 PF
VIN = 3.3V
VOUT = 2.5V
ILOAD = 0A to 2A
CO = 100 PF
+
LO = 10 PH
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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.
LM2852
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LM2852 2A 500/1500 kHz Synchronous Buck Regulator
1
1 Features
1 Input Voltage Range of 2.85 V to 5.5 V
Factory EEPROM Set Output Voltages from 0.8 V
to 3.3 V in 100-mV Increments
Maximum Load Current of 2 A
Voltage Mode Control
Internal Type-Three Compensation
Switching Frequency of 500 kHz or 1.5 MHz
Low Standby Current of 10 µA
Internal 60-mMOSFET Switches
Standard Voltage Options 0.8/1/1.2/1.5/1.8/2.5/3.3
V
2 Applications
Low Voltage Point of Load Regulation
Local Solution for FPGA/DSP/ASIC Core Power
Broadband Networking and Communications
Infrastructure
Portable Computing
space
3 Description
The LM2852 synchronous buck regulator is a high
frequency step-down switching voltage regulator
capable of driving up to a 2A load with excellent line
and load regulation. The LM2852 can accept an input
voltage between 2.85 V and
5.5 V and deliver an output voltage that is factory
programmable from 0.8 V to 3.3 V in 100-mV
increments. The LM2852 is available with a choice of
two switching frequencies –500 kHz (LM2852Y) or
1.5 MHz (LM2852X). It also features internal, type-
three compensation to deliver a low component count
solution. The exposed-pad HTSSOP-14 package
enhances the thermal performance of the LM2852.
Device Information(1)
PART NUMBER PACKAGE BODY SIZE (NOM)
LM2852 HTSSOP (14) 5.00 mm × 4.40 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application Circuit Figure 1. Efficiency vs ILOAD
2
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Table of Contents
1 Features.................................................................. 1
2 Applications ........................................................... 1
3 Description............................................................. 1
4 Revision History..................................................... 2
5 Pin Configuration and Functions......................... 3
6 Specifications......................................................... 4
6.1 Absolute Maximum Ratings ...................................... 4
6.2 ESD Ratings.............................................................. 4
6.3 Recommended Operating Conditions....................... 4
6.4 Thermal Information.................................................. 4
6.5 Electrical Characteristics........................................... 5
6.6 LM2852Y Typical Characteristics (500 kHz)............. 7
6.7 LM2852X Typical Characteristics (1500 kHz)........... 8
6.8 LM2852 Typical Characteristics (Both Y and X
Versions).................................................................... 9
7 Detailed Description............................................ 10
7.1 Overview................................................................. 10
7.2 Functional Block Diagram....................................... 10
7.3 Feature Description................................................. 11
7.4 Device Functional Modes........................................ 11
8 Application and Implementation ........................ 12
8.1 Application Information............................................ 12
8.2 Typical Application ................................................. 12
9 Power Supply Recommendations...................... 18
10 Layout................................................................... 18
10.1 Layout Guidelines ................................................. 18
10.2 Layout Example .................................................... 18
11 Device and Documentation Support................. 19
11.1 Device Support...................................................... 19
11.2 Community Resources.......................................... 19
11.3 Trademarks........................................................... 19
11.4 Electrostatic Discharge Caution............................ 19
11.5 Glossary................................................................ 19
12 Mechanical, Packaging, and Orderable
Information........................................................... 19
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision D (April 2013) to Revision E Page
Added 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.................................................................................................. 1
EN
SGND
SS
NC
PVIN
PVIN
SNS
NC
NC
PGND
PGND
SW
SW
AVIN
LM2852
1
2
3
4
5
7
6
14
13
12
11
10
8
9
3
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5 Pin Configuration and Functions
PWP Package
14-Pin HTSSOP
Top View
Pin Functions
PIN I/O DESCRIPTION
NAME NO.
AVIN 1 I Chip bias input pin. This provides power to the logic of the chip. Connect to the input voltage
or a separate rail.
EN 2 I Enable. Connect this pin to ground to disable the chip; connect to AVIN or leave floating to
enable the chip; enable is internally pulled up.
Exposed Connect to ground.
NC 5, 12, 13 No connect. These pins must be tied to ground or left floating in the application.
PGND 10, 11 G Power ground. Connect this to an internal ground plane or other large ground plane.
PVIN 6, 7 I Input supply pin. PVIN is connected to the input voltage. This rail connects to the source of
the internal power PFET.
SGND 3 G Signal ground.
SNS 14 O Output voltage sense pin. Connect this pin to the output voltage as close to the load as
possible.
SS 4 I Soft-start pin. Connect this pin to a small capacitor to control startup. The soft-start
capacitance range is restricted to values 1 nF to 50 nF.
SW 8, 9 O Switch pin. Connect to the output inductor.
4
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(1) 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.
(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and
specifications.
6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)(2)
MIN MAX UNIT
PVIN, AVIN, EN, SNS 6.5 V
Power dissipation Internally limited
14-Pin exposed pad HTSSOP package Infrared (15 sec) 220 °C
Vapor phase (60 sec) 215 °C
Maximum junction temperature 150 °C
Storage temperature, Tstg 65 150 °C
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
6.2 ESD Ratings VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted) MIN MAX UNIT
PVIN to GND 1.5 5.5 V
AVIN to GND 2.85 5.5 V
Junction temperature 40 125 °C
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
6.4 Thermal Information
THERMAL METRIC(1) LM2852
UNITPWP (HTTSOP)
14 PINS
RθJA Junction-to-ambient thermal resistance 39.2 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 24.1 °C/W
RθJB Junction-to-board thermal resistance 20.1 °C/W
ψJT Junction-to-top characterization parameter 0.6 °C/W
ψJB Junction-to-board characterization parameter 19.8 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 1.7 °C/W
5
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(1) VOUT measured in a non-switching, closed-loop configuration at the SNS pin.
6.5 Electrical Characteristics
AVIN = PVIN = 5 V unless otherwise indicated under the Test Conditions column. Limits apply over the junction temperature
(TJ) range of –40°C to 125°C (unless otherwise noted). Minimum and Maximum limits are ensured through test, design, or
statistical correlation. Typical values represent the most likely parametric norm at TJ= 25°C, and are provided for reference
purposes only.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SYSTEM PARAMETERS
VOUT Voltage
tolerance(1)
VOUT = 0.8-V option 0.782 0.818
V
VOUT = 1-V option 0.9775 1.0225
VOUT = 1.2-V option 1.173 1.227
VOUT = 1.5-V option 1.4663 1.5337
VOUT = 1.8-V option 1.7595 1.8405
VOUT = 2.5-V option 2.4437 2.5563
VOUT = 3-V option 2.9325 3.0675
VOUT = 3.3-V option 3.2257 3.3743
ΔVOUT/ΔAVIN Line regulation(1)
VOUT = 0.8 V, 1 V, 1.2 V, 1.5 V,
1.8 V or 2.5 V,
2.85 V AVIN 5.5 V
TJ= –40°C to
125°C 0.6%
TJ= 25°C 0.2%
VOUT = 3.3 V,
3.5 V AVIN 5.5 V
TJ= –40°C to
125°C 0.6%
TJ= 25°C 0.2%
ΔVOUT/ΔIOLoad regulation Normal operation TJ= 25°C 8 mV/A
VON UVLO threshold (AVIN)
Rising TJ= –40°C to
125°C 2.85 V
TJ= 25°C 2.47
Falling hysteresis TJ= –40°C to
125°C 85 210 mV
TJ= 25°C 150
rDSON-P PFET ON resistance Isw = 2 A TJ= –40°C to
125°C 140 m
TJ= 25°C 75
rDSON-N NFET ON resistance Isw = 2 A TJ= –40°C to
125°C 120 m
TJ= 25°C 55
RSS Soft-start resistance TJ= 25°C 400 k
ICL Peak current limit
threshold
LM2852X TJ= –40°C to
125°C 2.75 4.95
A
TJ= 25°C 4
LM2852Y TJ= –40°C to
125°C 2.25 3.65
TJ= 25°C 3
IQOperating current Non-switching TJ= –40°C to
125°C 2mA
TJ= 25°C 0.85
ISD Shutdown quiescent
current EN = 0 V TJ= –40°C to
125°C 25 µA
TJ= 25°C 10
RSNS Sense pin resistance TJ= 25°C 400 k
6
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Electrical Characteristics (continued)
AVIN = PVIN = 5 V unless otherwise indicated under the Test Conditions column. Limits apply over the junction temperature
(TJ) range of –40°C to 125°C (unless otherwise noted). Minimum and Maximum limits are ensured through test, design, or
statistical correlation. Typical values represent the most likely parametric norm at TJ= 25°C, and are provided for reference
purposes only.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
(2) The enable pin is internally pulled up, so the LM2852 is automatically enabled unless an external enable voltage is applied.
PWM
fosc
LM2852X 1500-kHz option. TJ= –40°C to
125°C 1050 1825 kHz
TJ= 25°C 1500
LM2852Y 500-kHz option. TJ= –40°C to
125°C 325 625 kHz
TJ= 25°C 500
Drange Duty cycle 0% 100%
ENABLE CONTROL(2)
VIH EN pin minimum high
input 75 % of
AVIN
VIL EN pin maximum low
input 25 % of
AVIN
IEN EN pin pullup current EN = 0 V TJ= 25°C 1.2 µA
THERMAL CONTROLS
TSD TJfor thermal shutdown TJ= 25°C 165 °C
TSD-HYS Hysteresis for thermal
shutdown TJ= 25°C 10 °C
0.1 1.0 10
87
88
89
90
91
92
93
94
95
EFFICIENCY (%)
ILOAD (A)
PVIN = 5.0V
-50 -25 0 25 50 75 100 125 150
TEMPERATURE (oC)
480
490
500
510
520
530
540
550
560
FREQUENCY (kHz)
VIN = 3.3V
VIN = 5V
0.1 1.0 10
84
86
88
90
92
94
96
PVIN = 3.3V
ILOAD (A)
EFFICIENCY (%)
PVIN = 5.0V
7
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6.6 LM2852Y Typical Characteristics (500 kHz)
Figure 2. Efficiency vs ILoad VOUT = 1.5 V Figure 3. Efficiency vs ILoad VOUT = 2.5 V
Figure 4. Efficiency vs ILoad VOUT = 3.3 V Figure 5. Frequency vs Temperature
0.1 1.0 10
50
55
60
65
70
75
80
85
90
EFFICIENCY (%)
ILOAD (A)
PVIN = 5.0V
-50 -25 0 25 50 75 80 85 90
TEMPERATURE (oC)
FREQUENCY (kHz)
PVIN = 3.3V
PVIN = 5.0V
1200
1250
1300
1350
1400
1450
1500
1550
1600
0.1 1.0 10
45
50
55
60
65
70
75
80
85
EFFICIENCY (%)
ILOAD (A)
PVIN = 3.3V
PVIN = 5.0V
ILOAD (A)
0.1 1.0 10
40
50
60
70
80
90
100
EFFICIENCY (%)
PVIN = 3.3V
PVIN = 5.0V
8
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6.7 LM2852X Typical Characteristics (1500 kHz)
Figure 6. Efficiency vs ILoad VOUT = 1.5 V Figure 7. Efficiency vs ILoad VOUT = 2.5 V
Figure 8. Efficiency vs ILoad VOUT = 3.3 V Figure 9. Frequency vs Temperature
-50 -25 0 25 50 75 100 125 150
TEMPERATURE (oC)
40
50
60
70
80
90
100
NFET RDSON (m:)
PVIN = 3.3V
PVIN = 5.0V
-50 -25 0 25 50 75 100 125 150
TEMPERATURE (oC)
50
60
70
80
90
100
110
120
130
PFET RDSON (m:)
PVIN = 3.3V
PVIN = 5.0V
9
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6.8 LM2852 Typical Characteristics (Both Y and X Versions)
Figure 10. NMOS Switch RDSON vs Temperature Figure 11. PMOS Switch RDSON vs Temperature
Ramp and Clock
Generator
AVIN
EN
PVIN
Gate
Drive SW
PGND
+
-
+
-
SS
SNS
Error
Amp
PWM
Comp
OscillatorReference
UVLO DAC
Zc2
400 k:
200 k:200 k:
20 pF
SGND
Zc1
Current Limit
10
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7 Detailed Description
7.1 Overview
The LM2852 is a DC-DC synchronous buck regulator. Integration of the PWM controller, power switches and
compensation network greatly reduces the component count required to implement a switching power supply.
7.2 Functional Block Diagram
CSS = 3.3 nF CO = 100 PF
PVIN
AVIN
EN
SS SGND PGND
SNS
SW
LM2852Y
+
VOUT = 1.5V
ILOAD = 0A to 2A
LO = 10 PH
CIN = 47 PF1 PF
PVIN = 3.3VAVIN = 5V
11
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7.3 Feature Description
7.3.1 Split-Rail Operation
The LM2852 can be powered using two separate voltages for AVIN and PVIN. AVIN is the supply for the control
logic; PVIN is the supply for the power FETs. The output filter components need to be chosen based on the
value of PVIN. For PVIN levels lower than 3.3 V, use output filter component values recommended for 3.3 V.
PVIN must always be equal to or less than AVIN.
Figure 12. Split-Rail Operation
7.3.2 Switch Node Protection
The LM2852 includes protection circuitry that monitors the voltage on the switch pin. Under certain conditions,
switching is disabled in order to protect the switching devices. One result of the protection circuitry may be
observed when power to the LM2852 is applied with no or light load on the output. The output regulates to the
rated voltage, but no switching may be observed. As soon as the output is loaded, the LM2852 begins normal
switching operation.
7.4 Device Functional Modes
The LM2852 Enable pin is internally pulled up so that the part is enabled anytime the input voltage exceeds the
UVLO threshold. A pulldown resistor can be used to set the enable input to low.
IRMS = ILOAD D(1-D)
CSS
PVIN
AVIN
EN
SS SGND PGND
SNS
SW
LM2852
+
VOUT = 1.8V
ILOAD = 0A to 2A
LO
CIN
VIN = 3.3V
Cf
Rf
CINX CO
U1
12
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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 must
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The LM2852 is a DC-DC synchronous buck regulator capable of driving a maximum load current of 2A, with an
input range of 2.85 V to 5.5 V and a variable output range of 0.8 V to 3.3 V. Figure 13 is a schematic example of
a typical application.
8.2 Typical Application
Figure 13. LM2852 Example Circuit Schematic
8.2.1 Design Requirements
A typical application requires only four components: an input capacitor, a soft-start capacitor, an output filter
capacitor and an output filter inductor. To properly size the components for the application, the designer needs
the following parameters: input voltage range, output voltage, output current range, and required switching
frequency. These four main parameters affect the choices of component available to achieve a proper system
behavior.
8.2.2 Detailed Design Procedure
8.2.2.1 Input Capacitor (CIN)
Fast switching of large currents in the buck converter places a heavy demand on the voltage source supplying
PVIN. The input capacitor, CIN, supplies extra charge when the switcher needs to draw a burst of current from
the supply. The RMS current rating and the voltage rating of the CIN capacitor are therefore important in the
selection of CIN. The RMS current specification can be approximated by Equation 1:
where
D is the duty cycle, VOUT/VIN. CIN also provides filtering of the supply. (1)
Trace resistance and inductance degrade the benefits of the input capacitor, so CIN must be placed very close to
PVIN in the layout. A 22-µF or 47-µF ceramic capacitor is typically sufficient for CIN. In parallel with the large
input capacitance a smaller capacitor may be added such as a 1-µF ceramic for higher frequency filtering.
't = C I
'V= 100 PF3A
3V = 100 Ps
13
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Typical Application (continued)
8.2.2.2 Soft-Start Capacitor (CSS)
The DAC that sets the reference voltage of the error amp sources a current through a resistor to set the
reference voltage. The reference voltage is one half of the output voltage of the switcher due to the 200 k
divider connected to the SNS pin. Upon start-up, the output voltage of the switcher tracks the reference voltage
with a two to one ratio as the DAC current charges the capacitance connected to the reference voltage node.
Internal capacitance of 20 pF is permanently attached to the reference voltage node which is also connected to
the soft-start pin, SS. Adding a soft-start capacitor externally increases the time it takes for the output voltage to
reach its final level.
The charging time required for the reference voltage can be estimated using the RC time constant of the DAC
resistor and the capacitance connected to the SS pin. Three RC time constant periods are needed for the
reference voltage to reach 95% of its final value. The actual start-up time varies with differences in the DAC
resistance and higher-order effects.
If little or no soft-start capacitance is connected, then the start-up time may be determined by the time required
for the current limit current to charge the output filter capacitance. The capacitor charging equation I = C ΔV/Δt
can be used to estimate the start-up time in this case. For example, a part with a 3-V output, a 100-µF output
capacitance and a 3-A current limit threshold would require a time of 100 µs, seen in Equation 2:
(2)
Since it is undesirable for the power supply to start up in current limit, a soft-start capacitor must be chosen to
force the LM2852 to start up in a more controlled fashion based on the charging of the soft-start capacitance. In
this example, suppose a 3 ms start time is desired. Three time constants are required for charging the soft-start
capacitor to 95% of the final reference voltage. So in this case RC = 1 ms. The DAC resistor, R, is 400 kso C
can be calculated to be 2.5 nF. A 2.7-nF ceramic capacitor can be chosen to yield approximately a 3 ms start-up
time.
8.2.2.3 Soft-Start Capacitor (CSS) and Fault Conditions
Various fault conditions such as short circuit and UVLO of the LM2852 activate internal circuitry designed to
control the voltage on the soft-start capacitor. For example, during a short circuit current limit event, the output
voltage typically falls to a low voltage. During this time, the soft-start voltage is forced to track the output so that
once the short is removed, the LM2852 can restart gracefully from whatever voltage the output reached during
the short circuit event. The range of soft-start capacitors is therefore restricted to values 1 nF to 50 nF.
8.2.2.4 Compensation
The LM2852 provides a highly integrated solution to power supply design. The compensation of the LM2852,
which is type-three, is included on-chip. The benefit to integrated compensation is straightforward, simple power
supply design. Since the output filter capacitor and inductor values impact the compensation of the control loop,
the range of L, C and CESR values is restricted in order to ensure stability.
14
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Typical Application (continued)
8.2.2.5 Output Filter Values
Table 1 details the recommended inductor and capacitor ranges for the LM2852 that are suggested for various
typical output voltages. Values slightly different than those recommended may be used, however the phase
margin of the power supply may be degraded.
Table 1. Output Filter Values
FREQUENCY
OPTION VOUT (V) PVIN (V) L (µH) C (µF) CESR (m)
MIN MAX MIN MAX MIN MAX
LM2852Y
(500 kHz)
0.8 3.3 10 15 100 220 70 200
0.8 5 10 15 100 120 70 200
1 3.3 10 15 100 180 70 200
1 5 10 15 100 180 70 200
1.2 3.3 10 15 100 180 70 200
1.2 5 15 22 100 120 70 200
1.5 3.3 10 15 100 120 70 200
1.5 5 22 22 100 120 70 200
1.8 3.3 10 15 100 120 100 200
1.8 5 22 33 100 120 100 200
2.5 3.3 6.8 10 68 120 95 275
2.5 5 15 22 68 120 95 275
3.3 5 15 22 68 100 100 275
LM2852X
(1500 kHz)
0.8 3.3
1 10 The 1500-kHz version is
designed for ceramic output
capacitors, which typically have
very low ESR (< 10 m.)
0.8 5
1 3.3
1 5
1.2 3.3
1.2 5
1.5 3.3
1.5 5
1.8 3.3
1.8 5
2.5 3.3
2.5 5
3.3 5
'IL = 500 kHz x 15 PH
1.2V x
5V (5V - 1.2V) = 121.6 mA
'IL = f x L
D x (VIN - VOUT)
15
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8.2.2.6 Choosing an Inductance Value
The current ripple present in the output filter inductor is determined by the input voltage, output voltage, switching
frequency and inductance according to Equation 3:
where
ΔILis the peak-to-peak current ripple.
D is the duty cycle VOUT/VIN.
VIN is the input voltage applied to the PVIN pin.
VOUT is the output voltage of the switcher.
f is the switching frequency.
L is the inductance of the output filter inductor. (3)
Knowing the current ripple is important for inductor selection since the peak current through the inductor is the
load current plus one half the ripple current. Care must be taken to ensure the peak inductor current does not
reach a level high enough to trip the current limit circuitry of the LM2852.
As an example, consider a 5-V to 1.2-V conversion and a 500-kHz switching frequency. According to Table 1, a
15-µH inductor may be used. Calculating the expected peak-to-peak ripple, as seen in Equation 4.
(4)
The maximum inductor current for a 2-A load would therefore be 2 A plus 60.8 mA, 2.0608 A. As shown in the
ripple equation, the current ripple is inversely proportional to inductance.
8.2.2.7 Output Filter Inductors
Once the inductance value is chosen, the key parameter for selecting the output filter inductor is its saturation
current (Isat) specification. Typically Isat is given by the manufacturer as the current at which the inductance of the
coil falls to a certain percentage of the nominal inductance. The Isat of an inductor used in an application must be
greater than the maximum expected inductor current to avoid saturation. Table 2 lists the inductors that may be
suitable in LM2852 applications.
Table 2. LM2852 Output Filter Inductors
INDUCTANCE (µH) PART NUMBER VENDOR
1 DO1608C-102 Coilcraft
1 DO1813P-102HC Coilcraft
6.8 DO3316P-682 Coilcraft
7 MSS1038-702NBC Coilcraft
10 DO3316P-103 Coilcraft
10 MSS1038-103NBC Coilcraft
12 MSS1038-123NBC Coilcraft
15 D03316P-153 Coilcraft
15 MSS1038-153NBC Coilcraft
18 MSS1038-183NBC Coilcraft
22 DO3316P-223 Coilcraft
22 MSS1038-223NBC Coilcraft
22 DO3340P-223 Coilcraft
27 MSS1038-273NBC Coilcraft
33 MSS1038-333NBC Coilcraft
33 DO3340P-333 Coilcraft
16
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8.2.2.8 Output Filter Capacitors
The capacitors that may be used in the output filter with the LM2852 are limited in value and ESR range
according to Table 1.Table 3 lists some examples of capacitors that can typically be used in an LM2852
application.
Table 3. LM2852 Output Filter Capacitors
CAPACITANCE (µF) PART NUMBER CHEMISTRY VENDOR
10 GRM31MR61A106KE19 Ceramic Murata
10 GRM32DR61E106K Ceramic Murata
68 595D686X_010C2T Tantalum Vishay - Sprague
68 595D686X_016D2T Tantalum Vishay - Sprague
100 595D107X_6R3C2T Tantalum Vishay - Sprague
100 595D107X_016D2T Tantalum Vishay - Sprague
100 NOSC107M004R0150 Niobium Oxide AVX
100 NOSD107M006R0100 Niobium Oxide AVX
120 595D127X_004C2T Tantalum Vishay - Sprague
120 595D127X_010D2T Tantalum Vishay - Sprague
150 595D157X_004C2T Tantalum Vishay - Sprague
150 595D157X_016D2T Tantalum Vishay - Sprague
150 NOSC157M004R0150 Niobium Oxide AVX
150 NOSD157M006R0100 Niobium Oxide AVX
220 595D227X_004D2T Tantalum Vishay - Sprague
220 NOSD227M004R0100 Niobium Oxide AVX
220 NOSE227M006R0100 Niobium Oxide AVX
Table 4. Bill of Materials for 500kHz (LM2852Y) 3.3 VIN to 1.8 VOUT Conversion
ID PART NUMBER TYPE SIZE PARAMETERS QTY VENDOR
U1LM2852YMXA-1.8 2-A buck HTSSOP-14 1 TI
LODO3316P-153 Inductor 15 µH 1 Coilcraft
CO* 595D107X_6R3C2T Capacitor Case Code “C” 100 µF ±20% 1 Vishay-Sprague
CIN GRM32ER60J476ME20B Capacitor 1210 47 µF/X5R/6.3V 1 Murata
CINX GRM21BR71C105KA01B Capacitor 0805 1 µF/X7R/16V 1 Murata
CSS VJ0805Y272KXXA Capacitor 0805 2.7 nF ±10% 1 Vishay-Vitramon
RfCRCW060310R0F Resistor 0603 10 ±10% 1 Vishay-Dale
CfGRM21BR71C105KA01B Capacitor 0805 1 µF/X7R/16V 1 Murata
Table 5. Bill of Materials for 1500-kHz (LM2852X) 3.3-V to 1.8-V Conversion
ID PART NUMBER TYPE SIZE PARAMETERS QTY VENDOR
U1LM2852XMXA-1.8 2-A buck HTSSOP-14 1 TI
L0DO1813P-102HC Inductor 1 µH 1 Coilcraft
C0GRM32DR61E106K Capacitor 1210 10 µF/X5R/25V 1 Murata
CIN GRM32ER60J476ME20B Capacitor 1210 47 µF/X5R/6.3V 1 Murata
CINX GRM21BR71C105KA01B Capacitor 0805 1 µF/X7R/16V 1 Murata
CSS VJ0805Y272KXXA Capacitor 0805 2.7 nF ±10% 1 Vishay-Vitramon
RfCRCW060310R0F Resistor 0603 10 ±10% 1 Vishay-Dale
CfGRM21BR71C105KA01B Capacitor 0805 1 µF/X7R/16V 1 Murata
2.5 3 3.5 4 4.5 5 5.5
VIN (V)
5
7
9
11
13
15
17
IQ SHUTDOWN (PA)
25oC
85oC
125oC
-40oC
2.5 3 3.5 4 4.5 5 5.5
VIN (V)
500
600
700
800
900
1000
1100
IQ (PA)
25oC
85oC
125oC
-40oC
17
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8.2.3 Application Curves
Figure 14. Shutdown Current vs VIN Figure 15. Quiescent Current (Non-Switching) vs VIN
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9 Power Supply Recommendations
The LM2852 is designed to operate from various DC power supplies. If so, VIN input must be protected from
reversal voltage and voltage dump over 6.5 V. The impedance of the input supply rail must be low enough that
the input current transient does not cause drop below VIN UVLO level. If the input supply is connected by using
long wires, additional bulk capacitance may be required in addition to normal input capacitor.
10 Layout
10.1 Layout Guidelines
These are several guidelines to follow while designing the PCB layout for an LM2852 application.
The input bulk capacitor, CIN, must be placed very close to the PVIN pin to keep the resistance as low as
possible between the capacitor and the pin. High-current levels are present in this connection
All ground connections must be tied together. Use a broad ground plane, for example a completely filled back
plane, to establish the lowest resistance possible between all ground connections
The sense pin connection must be made as close to the load as possible so that the voltage at the load is the
expected regulated value. The sense line must not run too close to nodes with high EMI (such as the switch
node) to minimize interference
The switch node connections must be low resistance to reduce power losses. Low resistance means the
trace between the switch pin and the inductor must be wide. However, the area of the switch node must not
be too large since EMI increases with greater area. So connect the inductor to the switch pin with a short, but
wide trace. Other high current connections in the application such as PVIN and VOUT assume the same trade
off between low resistance and EMI
Allow area under the chip to solder the entire exposed die attach pad to ground for improved thermal and
electrical performance
10.2 Layout Example
Figure 16. PCB Layout Example
19
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11 Device and Documentation Support
11.1 Device Support
11.1.1 Third-Party Products Disclaimer
TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT
CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES
OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER
ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.
11.2 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
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Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
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11.3 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.4 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.
11.5 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.