LF444
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SNOSC04D –MAY 1998–REVISED MARCH 2013
LF444 Quad Low Power JFET Input Operational Amplifier
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1FEATURES DESCRIPTION
The LF444 quad low power operational amplifier
23• ¼ Supply Current of a LM148: 200 μA/Amplifier provides many of the same AC characteristics as the
(max) industry standard LM148 while greatly improving the
• Low Input Bias Current: 50 pA (max) DC characteristics of the LM148. The amplifier has
• High Gain Bandwidth: 1 MHz the same bandwidth, slew rate, and gain (10 kΩload)
as the LM148 and only draws one fourth the supply
• High Slew Rate: 1 V/μscurrent of the LM148. In addition the well matched
• Low Noise Voltage for Low Power 35 nV/√Hz high voltage JFET input devices of the LF444 reduce
• Low Input Noise Current 0.01 pA/√Hz the input bias and offset currents by a factor of
10,000 over the LM148. The LF444 also has a very
• High Input Impedance: 1012Ωlow equivalent input noise voltage for a low power
• High Gain: 50k (min) amplifier.
The LF444 is pin compatible with the LM148 allowing
an immediate 4 times reduction in power drain in
many applications. The LF444 should be used
wherever low power dissipation and good electrical
characteristics are the major considerations.
Simplified Schematic Connection Diagram
Figure 1. 1/4 Quad Figure 2. PDIP/SOIC Package
Top View
See Package Number NAK0014D, D0014A or
NFF0014A
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.
1Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2BI-FET is a trademark of Texas Instruments.
3All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Copyright © 1998–2013, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
LF444
SNOSC04D –MAY 1998–REVISED MARCH 2013
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Absolute Maximum Ratings(1)(2)(3)
LF444A LF444
Supply Voltage ±22V ±18V
Differential Input Voltage ±38V ±30V
Input Voltage Range(4) ±19V ±15V
Output Short CircuitDuration(5) Continuous Continuous
NAK Package D, NFF
Packages
Power Dissipation(6)(7) 900 mW 670 mW
Tjmax 150°C 115°C
θjA (Typical) 100°C/W 85°C/W
LF444A/LF444
Operating Temperature Range See(8)
ESD Tolerance(9) Rating to be determined
Storage Temperature Range −65°C ≤TA≤150°C
Soldering Information Dual-In-Line Packages (Soldering, 10 sec.) 260°C
Small Outline Package Vapor Phase (60 sec.) 215°C
Infrared (15 sec.) 220°C
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions for
which the device is functional, but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which ensure specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
(2) If Military/Aerospace specified devices are required, please contact the TI Sales Office/ Distributors for availability and specifications.
(3) Refer to RETS444X for LF444MD military specifications.
(4) Unless otherwise specified the absolute maximum negative input voltage is equal to the negative power supply voltage.
(5) Any of the amplifier outputs can be shorted to ground indefinitely, however, more than one should not be simultaneously shorted as the
maximum junction temperature will be exceeded.
(6) For operating at elevated temperature, these devices must be derated based on a thermal resistance of θjA.
(7) Max. Power Dissipation is defined by the package characteristics. Operating the part near the Max. Power Dissipation may cause the
part to operate outside ensured limits.
(8) The LF444A is available in both the commercial temperature range 0°C ≤TA≤70°C and the military temperature range −55°C ≤TA≤
125°C. The LF444 is available in the commercial temperature range only. The temperature range is designated by the position just
before the package type in the device number. A “C” indicates the commercial temperature range and an “M” indicates the military
temperature range. The military temperature range is available in “NAK” package only.
(9) Human body model, 1.5 kΩin series with 100 pF.
DC Electrical Characteristics (1)
Symbol Parameter Conditions LF444A LF444 Units
Min Typ Max Min Typ Max
VOS Input Offset Voltage RS= 10k, TA= 25°C 2 5 3 10 mV
0°C ≤TA≤+70°C 6.5 12 mV
−55°C ≤TA≤+125°C 8 mV
ΔVOS/ΔT Average TC of Input Offset RS= 10 kΩ10 10 μV/°C
Voltage
IOS Input Offset Current VS= ±15V(1) (2) Tj= 25°C 5 25 5 50 pA
Tj= 70°C 1.5 1.5 nA
Tj= 125°C 10 nA
IBInput Bias Current VS= ±15V(1) (2) Tj= 25°C 10 50 10 100 pA
Tj= 70°C 3 3 nA
Tj= 125°C 20 nA
(1) Unless otherwise specified the specifications apply over the full temperature range and for VS= ±20V for the LF444A and for VS= ±15V
for the LF444. VOS, IB, and IOS are measured at VCM = 0.
(2) The input bias currents are junction leakage currents which approximately double for every 10°C increase in the junction temperature,
Tj. Due to limited production test time, the input bias currents measured are correlated to junction temperature. In normal operation the
junction temperature rises above the ambient temperature as a result of internal power dissipation, PD. Tj= TA+θjAPDwhere θjA is the
thermal resistance from junction to ambient. Use of a heat sink is recommended if input bias current is to be kept to a minimum.
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DC Electrical Characteristics (1) (continued)
Symbol Parameter Conditions LF444A LF444 Units
Min Typ Max Min Typ Max
RIN Input Resistance Tj= 25°C 1012 1012 Ω
AVOL Large Signal Voltage Gain VS= ±15V, VO= ±10V 50 100 25 100 V/mV
RL= 10 kΩ, TA= 25°C
Over Temperature 25 15 V/mV
VOOutput Voltage Swing VS= ±15V, RL= 10 kΩ±12 ±13 ±12 ±13 V
VCM Input Common-Mode ±16 +18 ±11 +14 V
Voltage Range −17 −12 V
CMRR Common-Mode RS≤10 kΩ80 100 70 95 dB
Rejection Ratio
PSRR Supply Voltage See(3) 80 100 70 90 dB
Rejection Ratio
ISSupply Current 0.6 0.8 0.6 1.0 mA
(3) Supply voltage rejection ratio is measured for both supply magnitudes increasing or decreasing simultaneously in accordance with
common practice from ±15V to ±5V for the LF444 and from ±20V to ±5V for the LF444A.
AC Electrical Characteristics (1)
Symbol Parameter Conditions LF444A LF444 Units
Min Typ Max Min Typ Max
Amplifier-to-Amplifier −120 −120 dB
Coupling
SR Slew Rate VS= ±15V, TA= 25°C 1 1 V/μs
GBW Gain-Bandwidth Product VS= ±15V, TA= 25°C 1 1 MHz
enEquivalent Input Noise Voltage TA= 25°C, RS= 100Ω, 35 35 nV/√Hz
f = 1 kHz
inEquivalent Input Noise Current TA= 25°C, f = 1 kHz 0.01 0.01 pA/√Hz
(1) Unless otherwise specified the specifications apply over the full temperature range and for VS= ±20V for the LF444A and for VS= ±15V
for the LF444. VOS, IB, and IOS are measured at VCM = 0.
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Typical Performance Characteristics
Input Bias Current Input Bias Current
Figure 3. Figure 4.
Positive Common-Mode
Supply Current Input Voltage Limit
Figure 5. Figure 6.
Negative Common-Mode
Input Voltage Limit Positive Current Limit
Figure 7. Figure 8.
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Typical Performance Characteristics (continued)
Negative Current Limit Output Voltage Swing
Figure 9. Figure 10.
Output Voltage Swing Gain Bandwidth
Figure 11. Figure 12.
Bode Plot Slew Rate
Figure 13. Figure 14.
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Typical Performance Characteristics (continued)
Distortion
vs Undistorted Output
Frequency Voltage Swing
Figure 15. Figure 16.
Open Loop Common-Mode
Frequency Response Rejection Ratio
Figure 17. Figure 18.
Power Supply Equivalent Input
Rejection Ratio Noise Voltage
Figure 19. Figure 20.
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Typical Performance Characteristics (continued)
Open Loop Voltage Gain Output Impedance
Figure 21. Figure 22.
Inverter Settling Time
Figure 23.
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Pulse Response
RL= 10 kΩ, CL= 10 pF
Small Signal Inverting Large Signal Inverting
Figure 24. Figure 25.
Small Signal Non-Inverting Large Signal Non-Inverting
Figure 26. Figure 27.
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SNOSC04D –MAY 1998–REVISED MARCH 2013
APPLICATION HINTS
This device is a quad low power op amp with JFET input devices ( BI-FET™). These JFETs have large reverse
breakdown voltages from gate to source and drain eliminating the need for clamps across the inputs. Therefore,
large differential input voltages can easily be accommodated without a large increase in input current. The
maximum differential input voltage is independent of the supply voltages. However, neither of the input voltages
should be allowed to exceed the negative supply as this will cause large currents to flow which can result in a
destroyed unit.
Exceeding the negative common-mode limit on either input will force the output to a high state, potentially
causing a reversal of phase to the output. Exceeding the negative common-mode limit on both inputs will force
the amplifier output to a high state. In neither case does a latch occur since raising the input back within the
common-mode range again puts the input stage and thus the amplifier in a normal operating mode.
Exceeding the positive common-mode limit on a single input will not change the phase of the output; however, if
both inputs exceed the limit, the output of the amplifier will be forced to a high state.
The amplifiers will operate with a common-mode input voltage equal to the positive supply; however, the gain
bandwidth and slew rate may be decreased in this condition. When the negative common-mode voltage swings
to within 3V of the negative supply, an increase in input offset voltage may occur.
Each amplifier is individually biased to allow normal circuit operation with power supplies of ±3.0V. Supply
voltages less than these may degrade the common-mode rejection and restrict the output voltage swing.
The amplifiers will drive a 10 kΩload resistance to ±10V over the full temperature range. If the amplifier is forced
to drive heavier load currents, however, an increase in input offset voltage may occur on the negative voltage
swing and finally reach an active current limit on both positive and negative swings.
Precautions should be taken to ensure that the power supply for the integrated circuit never becomes reversed in
polarity or that the unit is not inadvertently installed backwards in a socket as an unlimited current surge through
the resulting forward diode within the IC could cause fusing of the internal conductors and result in a destroyed
unit.
As with most amplifiers, care should be taken with lead dress, component placement and supply decoupling in
order to ensure stability. For example, resistors from the output to an input should be placed with the body close
to the input to minimize “pick-up” and maximize the frequency of the feedback pole by minimizing the
capacitance from the input to ground.
A feedback pole is created when the feedback around any amplifier is resistive. The parallel resistance and
capacitance from the input of the device (usually the inverting input) to AC ground set the frequency of the pole.
In many instances the frequency of this pole is much greater than the expected 3 dB frequency of the closed
loop gain and consequently there is negligible effect on stability margin. However, if the feedback pole is less
than approximately 6 times the expected 3 dB frequency a lead capacitor should be placed from the output to the
input of the op amp. The value of the added capacitor should be such that the RC time constant of this capacitor
and the resistance it parallels is greater than or equal to the original feedback pole time constant.
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Typical Application
Figure 28. pH Probe Amplifier/Temperature Compensator
***For R2 = 50k, R4 = 330k ±1%
For R2 = 100k, R4 = 75k ±1%
For R2 = 200k, R4 = 56k ±1%
**Polystyrene
*Film resistor type RN60C
To calibrate, insert probe in pH =7 solution. Set the “TEMPERATURE ADJUST” pot, R2, to correspond to the solution
temperature: full clockwise for 0°C, and proportionately for intermediate temperatures, using a turns-counting dial.
Then set “CALIBRATE” pot so output reads 7V.
Typical probe = Ingold Electrodes #465-35
Detailed Schematic
Figure 29. 1/4 Quad
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SNOSC04D –MAY 1998–REVISED MARCH 2013
REVISION HISTORY
Changes from Revision C (March 2013) to Revision D Page
• Changed layout of National Data Sheet to TI format .......................................................................................................... 10
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PACKAGE OPTION ADDENDUM
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Addendum-Page 1
PACKAGING INFORMATION
Orderable Device Status
(1)
Package Type Package
Drawing Pins Package
Qty Eco Plan
(2)
Lead finish/
Ball material
(6)
MSL Peak Temp
(3)
Op Temp (°C) Device Marking
(4/5)
Samples
LF444ACN/NOPB ACTIVE PDIP NFF 14 25 RoHS & Green Call TI | SN Level-1-NA-UNLIM 0 to 70 LF444ACN
LF444CM NRND SOIC D 14 55 Non-RoHS &
Non-Green Call TI Call TI 0 to 70 LF444CM
LF444CM/NOPB ACTIVE SOIC D 14 55 RoHS & Green SN Level-1-260C-UNLIM 0 to 70 LF444CM
LF444CMX/NOPB ACTIVE SOIC D 14 2500 RoHS & Green SN Level-1-260C-UNLIM 0 to 70 LF444CM
LF444CN/NOPB ACTIVE PDIP NFF 14 25 RoHS & Green Call TI | SN Level-1-NA-UNLIM 0 to 70 LF444CN
(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.
(4) 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 finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two
lines if the finish value exceeds the maximum column width.
PACKAGE OPTION ADDENDUM
www.ti.com 10-Dec-2020
Addendum-Page 2
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device Package
Type Package
Drawing Pins SPQ Reel
Diameter
(mm)
Reel
Width
W1 (mm)
A0
(mm) B0
(mm) K0
(mm) P1
(mm) W
(mm) Pin1
Quadrant
LF444CMX/NOPB SOIC D 14 2500 330.0 16.4 6.5 9.35 2.3 8.0 16.0 Q1
PACKAGE MATERIALS INFORMATION
www.ti.com 23-Sep-2013
Pack Materials-Page 1
*All dimensions are nominal
Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
LF444CMX/NOPB SOIC D 14 2500 367.0 367.0 35.0
PACKAGE MATERIALS INFORMATION
www.ti.com 23-Sep-2013
Pack Materials-Page 2
MECHANICAL DATA
N0014A
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N14A (Rev G)
NFF0014A
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