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LM4140
SNVS053F – JUNE 2000 – REVISED SEPTEMBER 2016
LM4140 High Precision Low Noise Low Dropout Voltage Reference
1 Features
3 Description
•
•
•
•
•
•
The LM4140 series of precision references are
designed to combine high accuracy, low drift, and
noise with low power dissipation in a small package.
1
•
•
•
•
High Initial Accuracy: 0.1%
Ultra-Low Noise
Low Temperature Coefficient: 3 ppm/°C (A Grade)
Low Voltage Operation: 1.8V
Low Dropout Voltage: 20 mV (Typical) at 1mA
Supply Current: 230 µA (Typical), ≤ 1 µA Disable
Mode
Enable Pin
Output Voltage Options: 1.024 V, 1.25 V, 2.048 V,
2.5 V, and 4.096 V
Custom Voltages From 0.5 V to 4.5 V
Temperature Range: 0°C to 70°C
The LM4140 is the industry's first reference with
output voltage options lower than the bandgap
voltage.
The key to the advance performance of the LM4140
is the use of EEPROM registers and CMOS DACs for
temperature coefficient curvature correction and
trimming of the output voltage accuracy of the device
during the final production testing.
The major advantage of this method is the much
higher resolution available with DACs than is
available economically with most methods used by
other bandgap references.
2 Applications
•
•
•
•
•
•
•
•
•
The low input and dropout voltage, low supply
current, and output drive capability of the LM4140
makes this product an ideal choice for battery
powered and portable applications.
Portable, Battery-Powered Equipment
Instrumentation and Test Equipment
Automotive
Industrial Process Control
Data Acquisition Systems
Medical Equipment
Precision Scales
Servo Systems
Battery Charging
The LM4140 is available in three grades (A, B, C)
with 0.1% initial accuracy and 3, 6, and 10 ppm/°C
temperature coefficients. For even lower temperature
coefficients, contact Texas Instruments.
The device performance is specified over the
temperature range 0°C to 70°C, and is available in
compact 8-pin package.
For other output voltage options from 0.5 V to 4.5 V,
contact Texas Instruments.
Device Information(1)
PART NUMBER
PACKAGE
LM4140
SOIC (8)
BODY SIZE (NOM)
4.90 mm × 3.91 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application
Input
2
6
VIN
5
NC
3
Output
VREF
COUT
1 …F
Enable
GND
1, 4 7, 8
Copyright © 2016, Texas Instruments Incorporated
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.
LM4140
SNVS053F – JUNE 2000 – REVISED SEPTEMBER 2016
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
4
4
4
4
5
6
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Typical Characteristics ..............................................
Detailed Description ............................................ 10
7.1 Overview ................................................................. 10
7.2 Functional Block Diagram ....................................... 10
7.3 Feature Description................................................. 10
7.4 Device Functional Modes........................................ 10
8
Application and Implementation ........................ 11
8.1 Application Information............................................ 11
8.2 Typical Applications ................................................ 14
9 Power Supply Recommendations...................... 20
10 Layout................................................................... 20
10.1 Layout Guidelines ................................................. 20
10.2 Layout Example .................................................... 20
11 Device and Documentation Support ................. 21
11.1
11.2
11.3
11.4
11.5
Receiving Notification of Documentation Updates
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
21
21
21
21
21
12 Mechanical, Packaging, and Orderable
Information ........................................................... 21
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision E (April 2013) to Revision F
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
•
Added Thermal Information table ........................................................................................................................................... 4
Changes from Revision D (April 2005) to Revision E
•
2
Page
Changed layout of National Semiconductor Data Sheet to TI format .................................................................................... 1
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5 Pin Configuration and Functions
D Package
8-Pin SOIC
Top View
Ground
1
8
Ground
VIN
2
7
Ground
Enable
3
6
VREF
Ground
4
5
NC
Not to scale
Pin Functions
PIN
NAME
NO.
TYPE (1)
DESCRIPTION
Enable
3
I
Pulled to input for normal operation. Forcing this pin to ground turns off the output.
Ground
1, 4, 7, 8
G
Negative supply or ground connection. These pins must be connected to ground.
NC
5
—
This pin must be left open.
VIN
2
I
Positive supply.
VREF
6
O
Reference output. Capable of sourcing up to 8 mA.
(1)
G = Ground, I = Input, O = Output
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
Maximum voltage on any input pin
MIN
MAX
UNIT
–0.3
5.6
V
345
mW
150
°C
Output short-circuit duration
Indefinite
Power dissipation (TA = 25°C) (2)
Storage temperature, Tstg
(1)
(2)
–65
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.
Without PCB copper enhancements. The maximum power dissipation must be derated at elevated temperatures and is limited by TJMAX
(maximum junction temperature), RθJA (junction to ambient thermal resistance) and TA (ambient temperature). The maximum power
dissipation at any temperature is: PDissMAX = (TJMAX − TA)/RθJA up to the value listed in the Absolute Maximum Ratings. The RθJA for
the 8-pin SOIC package is 160°C/W.
6.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±2000
Charged-device model (CDM), per JEDEC specification JESD22-C101 (2)
±200
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
NOM
MAX
UNIT
Ambient temperature
0
70
°C
Junction temperature
0
80
°C
6.4 Thermal Information
LM4140
THERMAL METRIC
(1)
D (SOIC)
UNIT
8 PINS
RθJA
Junction-to-ambient thermal resistance
119.3
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
52.3
°C/W
RθJB
Junction-to-board thermal resistance
60.3
°C/W
ψJT
Junction-to-top characterization parameter
14.5
°C/W
ψJB
Junction-to-board characterization parameter
59.7
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
—
°C/W
(1)
4
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
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6.5 Electrical Characteristics
VIN = 3 V for the 1.024-V and 1.25-V, VIN = 5 V for all other voltage options, VEN = VIN, COUT = 1 µF (1), ILOAD = 1 mA, and
TA = TJ = 25°C (unless otherwise noted)
PARAMETER
MIN (2)
TEST CONDITIONS
VREF
Output voltage initial
accuracy (4)
All versions
TCVREF/°C
Temperature coefficient
0°C ≤ TA ≤ 70°C
TYP (3)
1.024-V and 1.25-V options, 1.8 V ≤ VIN ≤ 5.5 V
Line regulation
6
C grade
10
TA = 25°C
50
0°C ≤ TA ≤ 70°C
1 mA ≤ ILOAD ≤ 8 mA
4.096-V option
1
0°C ≤ TA ≤ 70°C
TA = 25°C
5
0°C ≤ TA ≤ 70°C
60
ΔVREF
Thermal hysteresis (5)
0°C ≤ TA ≤ + 70°C
20
Operating voltage
1.024-V and 1.25-V options, IL = 1 mA to 8 mA, 0°C ≤ TA ≤ 70°C
IL = 8 mA
Dropout voltage (6)
IL = 1 mA
4.096-V option
IL = 8 mA
Output noise voltage (7)
VN
Supply current
ILOAD = 0 mA
IS(OFF)
Supply current
VEnable < 0.4 V
VH
Logic high input voltage
0°C ≤ TA ≤ 70°C
IH
Logic high input current
VL
Logic low input voltage
IL
Logic low input current
ISC
Short-circuit current
(3)
(4)
(5)
(6)
(7)
35
ppm/mA
TA = 25°C
ppm
ppm
5.5
20
40
160
235
0°C ≤ TA ≤ 70°C
0°C ≤ TA ≤ 70°C
400
TA = 25°C
20
40
195
270
0°C ≤ TA ≤ 70°C
0°C ≤ TA ≤ 70°C
490
TA = 25°C
230
0°C ≤ TA ≤ 70°C
µVPP
320
375
TA = 25°C
265
0°C ≤ TA ≤ 70°C
350
µA
400
TA = 25°C
0.01
0°C ≤ TA ≤ 70°C
1
0.8 × VIN
0°C ≤ TA ≤ 70°C
nA
0.4
1
8.5
µA
V
2
0°C ≤ TA ≤ 70°C
mV
45
TA = 25°C
TA = 25°C
V
45
TA = 25°C
2.2
4.096-V option
(1)
(2)
1.8
0.1 Hz to 10 Hz
All other voltage options
IS(ON)
20
150
1000 hours
VIN-VREF
ppm/V
200
150
Long-term stability
IL = 1 mA
300
250
TA = 25°C
ΔVREF
2.048-V and 2.5-V
options
ppm/°C
350
20
0°C ≤ TA ≤ 70°C
All other voltage options
Load regulation
3
B grade
TA = 25°C
All other voltage options,
Vref + 200 mV ≤ VIN ≤ 5.5 V
ΔVREF/ΔILOAD
UNIT
±0.1%
A grade
ΔVREF/ΔVIN
MAX (2)
20
V
nA
35
40
mA
For proper operation, a 1-µF capacitor is required between the output pin and the GND pin of the device.
Limits are 100% production tested at 25°C. Limits over the operating temperature range are ensured through correlation using Statistical
Quality Control (SQC) methods. The limits are used to calculate TI's Average Outgoing Quality Level (AOQL).
Typical numbers are at 25°C and represent the most likely parametric norm.
High temperature and mechanical stress associated with PCB assembly can have significant impact on the initial accuracy of the
LM4140 and may create significant shifts in VREF.
Thermal hysteresis is defined as the changes in 25°C output voltage before and after the cycling of the device from 0°C to 70°C.
Dropout voltage is defined as the minimum input to output differential voltage at which the output voltage drops by 0.5% below the value
measured with VIN = 3 V for the 1.024-V and 1.25-V, VIN = 5 V for all other voltage options.
The output noise is based on 1.024 V option. Output noise is linearly proportional to VREF.
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6.6 Typical Characteristics
TA = 25°C, no load, COUT = 1 µF, VIN = 3 V for 1.024-V and 1.25-V, and 5 V for all other voltage options, and VIN = VEN
(unless otherwise noted). The 1-µF output capacitor is actively discharged to ground (see ON/OFF Operation for more
details).
6
Figure 1. Power Up and Down Ground Current
Figure 2. Enable Response
Figure 3. Line Transient Response
Figure 4. Load Transient Response
Figure 5. Output Impedance
Figure 6. Power Supply Rejection Ratio
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Typical Characteristics (continued)
TA = 25°C, no load, COUT = 1 µF, VIN = 3 V for 1.024-V and 1.25-V, and 5 V for all other voltage options, and VIN = VEN
(unless otherwise noted). The 1-µF output capacitor is actively discharged to ground (see ON/OFF Operation for more
details).
1.024-V and 1.25-V options require 1.8-V supply
Figure 7. Dropout Voltage vs Load Current
Figure 8. Output Voltage Change vs Sink Current (ISINK)
Figure 9. Total Current (IS(OFF)) vs Supply Voltage
Figure 10. Total Current (IS(ON)) vs Supply Voltage
Figure 11. Spectral Noise Density (0.1 Hz to 10 Hz)
Figure 12. Spectral Noise Density (10 Hz to 100 kHz)
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Typical Characteristics (continued)
TA = 25°C, no load, COUT = 1 µF, VIN = 3 V for 1.024-V and 1.25-V, and 5 V for all other voltage options, and VIN = VEN
(unless otherwise noted). The 1-µF output capacitor is actively discharged to ground (see ON/OFF Operation for more
details).
8
Figure 13. Ground Current vs Load Current
Figure 14. Long-Term Drift
Figure 15. Load Regulation vs Temperature
Figure 16. Output Voltage vs Load Current
Figure 17. Line Regulation vs Temperature
Figure 18. IQ vs Temperature
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Typical Characteristics (continued)
TA = 25°C, no load, COUT = 1 µF, VIN = 3 V for 1.024-V and 1.25-V, and 5 V for all other voltage options, and VIN = VEN
(unless otherwise noted). The 1-µF output capacitor is actively discharged to ground (see ON/OFF Operation for more
details).
Figure 19. Short-Circuit Current vs Temperature
Figure 20. Dropout Voltage vs Load Current (VOUT) = 2 V
Figure 21. Typical Temperature Coefficient (Sample of 5 Parts)
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7 Detailed Description
7.1 Overview
The LM4140 device is a high-precision series voltage reference available in 5 difference output voltage options,
including the 1.024-V option below the bandgap voltage. The series reference can operate with input voltage as
low as VREF + 400 mV over temperature, consuming 400 µA or less over temperature depending on voltage
option. While in shutdown, the device consumes 10 nA (typical).
7.2 Functional Block Diagram
VIN
EN
±
Bandgap
Cell
+
VOUT
Copyright © 2016, Texas Instruments Incorporated
7.3 Feature Description
7.3.1 ON/OFF Operation
The LM4140 is designed to quickly reduce both VREF and IQ to zero when turned off. VREF is restored in less than
200 µs when turned on. During the turnoff, the charge across the output capacitor is discharged to ground
through internal circuitry.
The LM4140 is turned off by pulling the enable input low, and turned on by driving the input high. If this feature is
not to be used, the enable pin must be tied to the VIN to keep the reference on at all times (the enable pin must
not be left floating).
To ensure proper operation, the signal source used to drive the enable pin must be able to swing above and
below the specified high and low voltage thresholds which ensure an ON or OFF state (see Electrical
Characteristics).
The ON/OFF signal may come from either a totem-pole output, or an open-collector output with pullup resistor to
the LM4140 input voltage. This high-level voltage may exceed the LM4140 input voltage, but must remain within
the absolute maximum rating for the enable pin.
7.4 Device Functional Modes
Table 1 lists the operational modes of the LM4140.
Table 1. Operational Modes
10
ENABLE PIN
LOGIC STATE
DESCRIPTION
EN = VIN
1
Normal operation, device powered up
EN = Ground
0
Device in shutdown
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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 should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
8.1.1 Input Capacitors
Although not always required, TI recommends an input capacitor. A supply bypass capacitor on the input assures
that the reference is working from a source with low impedance, which improves stability. A bypass capacitor can
also improve transient response by providing a reservoir of stored energy that the reference can use in case
where the load current demand suddenly increases. The value used for CIN may be used without limit.
8.1.2 Output Capacitors
The LM4140 requires a 1-µF (nominally) output capacitor for loop stability (compensation) as well as transient
response. During the sudden changes in load current demand, the output capacitor must source or sink current
during the time it takes the control loop of the LM4140 to respond.
This capacitor must be selected to meet the requirements of minimum capacitance and equivalent series
resistance (ESR) range.
In general, the capacitor value must be at least 0.2 µF (over the actual ambient operating temperature), and the
ESR must be within the range indicated in Figure 22, Figure 23, and Figure 24.
Figure 22. 0.22-µF ESR Range
Figure 23. 1-µF ESR Range
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Application Information (continued)
Figure 24. 10-µF ESR Range
8.1.3 Tantalum Capacitors
Surface-mountable solid tantalum capacitors offer a good combination of small physical size for the capacitance
value, and ESR in the range required by the LM4140. The results of testing the LM4140 stability with surface
mount solid tantalum capacitors show good stability with values in the range of 0.1 µF. However, optimum
performance is achieved with a 1-µF capacitor.
Table 2 shows tantalum capacitors that have been verified as suitable for use with the LM4140.
Table 2. 1-µF Surface-Mount Tantalum Capacitor
Selection Guide
MANUFACTURER
PART NUMBER
Kemet
T491A105M010AS
NEC
NRU105N10
Siemens
B45196-E3105-K
Nichicon
F931C105MA
Sprague
293D105X0016A2T
Table 3. 2.2-µF Surface-Mount Tantalum Capacitor
Selection Guide
MANUFACTURER
PART NUMBER
Kemet
T491A225M010AS
NEC
NRU225M06
Siemens
B45196/2.2/10/10
Nichicon
F930J225MA
Sprague
293D225X0010A2T
8.1.4 Aluminum Electrolytic Capacitors
Although probably not a good choice for a production design, because of relatively large physical size, an
aluminium electrolytic capacitor can be used in the design prototype for an LM4140 reference. A 1-µF capacitor
meeting the ESR conditions can be used. If the operating temperature drops below 0°C, the reference may not
remain stable, as the ESR of the aluminium electrolytic capacitor increases, and may exceed the limits indicated
in the figures.
12
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8.1.5 Multilayer Ceramic Capacitors
Surface-mountable multilayer ceramic capacitors may be an attractive choice because of their relatively small
physical size and excellent RF characteristics.
However, they sometimes have an ESR values lower than the minimum required by the LM4140, and relatively
large capacitance change with temperature. The manufacturer's datasheet for the capacitor must be consulted
before selecting a value. Test results of LM4140 stability using multilayer ceramic capacitors show that a
minimum of 0.2 µF is usually required.
Table 4 shows the multilayer ceramic capacitors that have been verified as suitable for use with the LM4140.
Table 4. Surface-Mount Ceramic Capacitors Selection
Guide
CAPACITOR (µF)
MANUFACTURER
PART NUMBER
2.2
Tokin
1E225ZY5U-C203
2.2
Murata
GRM42-6Y5V225Z16
4.7
Tokin
1E475ZY5U-C304
8.1.6 Reverse Current Path
The P-channel Pass transistor used in the LM4140 has an inherent diode connected between the VIN and VREF
pins (see Figure 25).
Figure 25. Internal P-Channel Pass Transistor
Forcing the output to voltages higher than the input, or pulling VIN below voltage stored on the output capacitor
by more than a Vbe, forward biases this diode and current flows from the VREF terminal to VIN. No damage to the
LM4140 occurs under these conditions as long as the current flowing into the output pin does not exceed 50 mA.
8.1.7 Output Accuracy
Like all references, either series or shunt, the after assembly accuracy is made up of primarily three components:
initial accuracy itself, thermal hysteresis, and effects of the PCB assembly stress.
LM4140 provides an excellent output initial accuracy of 0.1% and temperature coefficient of 6ppm/°C (B Grade).
For best accuracy and precision, the LM4140 junction temperature must not exceed 70°C.
The thermal hysteresis curve on this datasheet are performance characteristics of three typical parts selected at
random from a sample of 40 parts.
Parts are mounted in a socket to minimize the effect of PCB's mechnical expansion and contraction. Readings
are taken at 25°C following multiple temperature cycles to 0°C and 70°C. The labels on the X axis of Figure 26
indicate the device temperature cycle prior to measurement at 25°C.
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Figure 26. Typical Thermal Hysteresis
The mechanical stress due to the PCB's mechanical and thermal stress can cause an output voltage shift more
than the true thermal coefficient of the device. References in surface mount packages are more susceptible to
these stresses because of the small amount of plastic molding which support the leads.
Following the recommendations on Layout can minimize the mechanical stress on the device.
8.2 Typical Applications
8.2.1 Precision DAC Reference
4.1 k
VIN
VIN
VREF
LM4140
4.7 F
50 k
10T
-4.096
100 k
EN
1 mA
GND
DAC
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Figure 27. Precision DAC Reference Schematic
8.2.1.1 Design Requirements
Generate a precision, temperature-stable voltage reference for use in digital-to-analog converter applications.
8.2.1.2 Detailed Design Procedure
Use LM4140-4.096 to generate a 4.096-V reference voltage. Use an adjustable resistor network to fine tune the
reference.
14
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Typical Applications (continued)
8.2.1.3 Application Curves
Figure 29. Typical Temperature Coefficient
(Sample of 5 Parts)
Figure 28. Output Voltage vs Load Current
8.2.2 Boosted Output Current
VIN
= 5.0 V
+
10 F
500
2N2907
VIN
100 k
VOUT= 2.5 V
at 50 mA
VREF
VIN
0V
On
Off
LM4140
± 2.5
+
10 F
EN
GND
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Figure 30. Boosted Output Current Schematic
8.2.2.1 Design Requirements
Generate a reference voltage that can support 50 mA.
8.2.2.2 Detailed Design Procedure
The LM4140-2.5 sets the reference level at 2.5 V. A 2N2907 PNP transistor is added, where the base is tied to
VIN through a 500-Ω resistor. The input current into the LM4140 increases with load current, which increases the
voltage drop across the 500-Ω resistor until the PNP transistor turns on and supplements the load current. See
Figure 30 for the circuit diagram.
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Typical Applications (continued)
8.2.3 Boosted Output Current With Current Limiter
12 k
VIN
= 4.5 V
to 5.5 V
+
1k
10 F
2 X 2N2907
IN
OUT
VIN
0V
On
Off
+
LM4140
± 2.5
VOUT= 2.5 V
at 50 mA
10 F
EN
GND
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Figure 31. Boosted Output Current With Current Limiter Schematic
8.2.3.1 Design Requirements
Generate a reference voltage that can support 50 mA with current limiter.
8.2.3.2 Detailed Design Procedure
The LM4140-2.5 sets the reference level at 2.5 V. Similar to Boosted Output Current, a PNP transistor is added
between VIN and the output. Another PNP transistor is added to sense the current between VIN and the load.
This additional transistor turns on above 50 mA, which turns off the pass transistor to the load.
8.2.4 Complimentary Outputs
VREF
VREF
VIN
R
LM4140
±
1 F
EN
+
±VREF
GND
R/2
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* Low Noise Op Amp such as OP-27
Figure 32. Complimentary Outputs Schematic
8.2.4.1 Design Requirements
Generate a positive and negative voltage reference.
8.2.4.2 Detailed Design Procedure
Use the LM4140 to generate the positive reference. Pass the reference into a unity gain inverting amplifier for a
negative reference output.
16
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Typical Applications (continued)
8.2.5 Voltage Reference With Force and Sense Output
VIN VREF
+
LM4140
100 k
1 F
±
EN
VREF
Force
VREF
Sense
GND
Copyright © 2016, Texas Instruments Incorporated
Figure 33. Voltage Reference With Force and Sense Output Schematic
8.2.5.1 Design Requirements
Design a voltage reference source that has a force and sense output.
8.2.5.2 Detailed Design Procedure
Use the LM4140 to generate a reference voltage. Pass this into the positive input terminal of an operation
amplifier, and use the negative input as the sense input from the load.
8.2.6 Precision Programmable Current Source
VIN
IN
OUT
R1
2.45 k
LM4140
EN
1 F
RSET
1k
GND
IREF
RL
VIN ! IOUT u RL
IOUT
VREF
1k
VREF
(
) IREF
(R1 RSET )
R1 2.45 k: for
IL 1 mA using LM4120 2.5
Copyright © 2016, Texas Instruments Incorporated
Figure 34. Precision Programmable Current Source Schematic
8.2.6.1 Design Requirements
Create a precision, adjustable current source.
8.2.6.2 Detailed Design Procedure
Use LM4140 to create reference voltage across an adjustable resistor, R1 + RSET. The voltage reference
creates a constant voltage source, and the adjustable resistor generates a proportional current.
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Typical Applications (continued)
8.2.7 Strain Gauge Conditioner for 350-Ω Bridge
Figure 35. Strain Gauge Conditioner for 350-Ω Bridge Schematic
8.2.7.1 Design Requirements
Supply a strain gage with a precision reference voltage.
8.2.7.2 Detailed Design Procedure
Use LM4140 to generate 4.096-V reference voltage. Use the reference to drive the strain gage bridge.
8.2.8 Bipolar Voltage References for Low Power ADC
Figure 36. Bipolar Voltage References for Low Power ADC Schematic
18
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Typical Applications (continued)
8.2.8.1 Design Requirements
Provide positive and negative reference voltages for the ADC1175 low power ADC.
8.2.8.2 Detailed Design Procedure
Use LM4140 to generate a 2.5-V positive reference voltage. The reference voltage is passed into an opamp to
act as a buffer and inverter, which yields a positive and negative reference. Transistors are used to drive the low
impedance inputs of the ADC1175.
8.2.9 Self-Biased Low Power ADC Reference With Trim Current Sources
Figure 37. Self-Biased Low Power ADC Reference With Trim Current Sources Schematic
8.2.9.1 Design Requirements
Use ADC1175 internal reference, but increase accuracy with trimming currents.
8.2.9.2 Detailed Design Procedure
The LM4140-2.5 sets a stable voltage source which is buffered and inverted, and the opamps are used as force
and sense amplifiers. This application does not require the transistor to drive low impedance nodes as the
internal reference voltages are still being used. The external circuitry is to increase the accuracy of the internal
reference.
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9 Power Supply Recommendations
While an input capacitor is not required, TI recommends using a 0.1 µF or larger capacitor to reduce noise on the
input and improve transient response.
10 Layout
10.1 Layout Guidelines
The simplest ways to reduce the stress related shifts are:
1. Mounting the device near the edges or the corners of the board where mechanical stress is at its minimum.
The center of the board generally has the highest mechanical and thermal expansion stress.
2. Mechanical isolation of the device by creating an island by cutting a U shape slot on the PCB for mounting
the device. This approach would also provide some thermal isolation from the rest of the circuit.
Figure 39 is a recommended printed-circuit board layout with a slot cut on three sides of the circuit layout to
serve as a strain relief.
10.2 Layout Example
Figure 38. Suggested Schematic and External Components
2
6
VIN
C2
1 F
U1
LM4140
C1
3
5
EN
1, 4
VOUT
TOUT
7 ,8
Copyright © 2016, Texas Instruments Incorporated
Figure 39. Suggested PCB Layout With Slot
20
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SNVS053F – JUNE 2000 – REVISED SEPTEMBER 2016
11 Device and Documentation Support
11.1 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper
right corner, click on Alert me to register and receive a weekly digest of any product information that has
changed. For change details, review the revision history included in any revised document.
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
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
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.
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21
PACKAGE OPTION ADDENDUM
www.ti.com
6-Aug-2021
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
LM4140ACM-1.0/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140A
CM1.0
LM4140ACM-1.2/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140A
CM1.2
LM4140ACM-2.0/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140A
CM2.0
LM4140ACM-2.5/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140A
CM2.5
LM4140ACM-4.1/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140A
CM4.1
LM4140ACMX-2.5/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140A
CM2.5
LM4140BCM-1.0/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140B
CM1.0
LM4140BCM-1.2/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140B
CM1.2
LM4140BCM-2.0/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140B
CM2.0
LM4140BCM-2.5/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140B
CM2.5
LM4140BCM-4.1/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140B
CM4.1
LM4140BCMX-1.0/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140B
CM1.0
LM4140BCMX-2.5/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140B
CM2.5
LM4140BCMX-4.1/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140B
CM4.1
LM4140CCM-1.0/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140C
CM1.0
LM4140CCM-1.2/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140C
CM1.2
LM4140CCM-2.0/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140C
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
Orderable Device
6-Aug-2021
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
CM2.0
LM4140CCM-2.5/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140C
CM2.5
LM4140CCM-4.1/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140C
CM4.1
LM4140CCMX-1.0/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140C
CM1.0
LM4140CCMX-1.2/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140C
CM1.2
LM4140CCMX-2.5/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140C
CM2.5
LM4140CCMX-4.1/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 70
4140C
CM4.1
(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
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