R1VO
VIN -
+
R3
VS
RPULL-UP
R2
OUTPUT
1
2
3
5
4
VIN-
GND
VS
VIN+
LM397
www.ti.com
SNOS977D –MAY 2001–REVISED MARCH 2013
LM397 Single General Purpose Voltage Comparator
Check for Samples: LM397
1FEATURES DESCRIPTION
The LM397 is a single voltage comparator with an
2• (TA= 25°C. Typical Values Unless Otherwise input common mode that includes ground. The
Specified). LM397 is designed to operate from a single 5V to
• 5-Pin SOT-23 Package 30V power supply or a split power supply. Its low
• Industrial Operating Range −40°C to +85°C supply current is virtually independent of the
magnitude of the supply voltage.
• Single or Dual Power Supplies The LM397 features an open collector output stage.
• Wide Supply Voltage Range 5V to 30V This allows the connection of an external resistor at
• Low Supply Current 300µA the output. The output can directly interface with TTL,
• Low Input Bias Current 7nA CMOS and other logic levels, by tying the resistor to
• Low Input Offset Current ±1nA different voltage levels (level translator).
• Low Input Offset Voltage ±2mV The LM397 is available in space saving 5-Pin SOT-
23 package and pin compatible to TI’s TL331, single
• Response Time 440ns (50mV Overdrive) differential comparator.
• Input Common Mode Voltage 0 to VS- 1.5V
APPLICATIONS
• A/D Converters
• Pulse, Square Wave Generators
• Peak Detector
• Industrial Applications
Typical Circuit
Connection Diagram
Top View
Figure 1. 5-Pin SOT-23 Package
See Package Number DBV0005A Figure 2. Inverting Comparator with Hysteresis
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.
2All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Copyright © 2001–2013, 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.
LM397
SNOS977D –MAY 2001–REVISED MARCH 2013
www.ti.com
Absolute Maximum Ratings(1)(2)
ESD Tolerance(3) Human Body Model 2KV
Machine Model 200V
VIN Differential 30V
Supply Voltages 30V or ±15V
Voltage at Input Pins −0.3V to 30V
Storage Temperature Range −65°C to +150°C
Junction Temperature(4) +150°C
Soldering Information Infrared or Convection (20 sec.) 235°C
Wave Soldering (10 sec.) 260°C
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but specific performance is not ensured. For ensured specifications and the test
conditions, see the Electrical Characteristics.
(2) If Military/Aerospace specified devices are required, please contact the TI Sales Office/ Distributors for availability and specifications.
(3) Human Body Model, applicable std. MIL-STD-883, Method 3015.7. Machine Model, applicable std. JESD22-A115-A (ESD MM std. of
JEDEC) Field-Induced Charge-Device Model, applicable std. JESD22-C101-C (ESD FICDM std. of JEDEC).
(4) The maximum power dissipation is a function of TJ(MAX),θJA. The maximum allowable power dissipation at any ambient temperature is
PD= (TJ(MAX) - TA)/ θJA . All numbers apply for packages soldered directly onto a PC board.
Operating Ratings(1)
Supply Voltage, VS5V to 30V
Temperature Range(2) −40°C to +85°C
Package Thermal Resistance(2) 5-Pin SOT-23 168°C/W
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but specific performance is not ensured. For ensured specifications and the test
conditions, see the Electrical Characteristics.
(2) The maximum power dissipation is a function of TJ(MAX),θJA. The maximum allowable power dissipation at any ambient temperature is
PD= (TJ(MAX) - TA)/ θJA . All numbers apply for packages soldered directly onto a PC board.
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SNOS977D –MAY 2001–REVISED MARCH 2013
Electrical Characteristics
Unless otherwise specified, all limits are ensured for TA= 25°C, VS= 5V, V−= 0V, VCM = V+/2 = VO.Boldface limits apply at
the temperature extremes.
Parameter Test Conditions Min(1) Typ(2) Max(1) Units
VOS Input Offset Voltage VS= 5V to 30V, 2 7 mV
VO= 1.4V, VCM = 0V 10
IOS Input Offset Current VO= 1.4V, VCM = 0V 1.6 50 nA
250
IBInput Bias Current VO= 1.4V, VCM = 0V 10 250 nA
400
ISSupply Current RL= Open, VS= 5V 0.25 0.7 mA
RL= Open, VS= 30V 0.30 2
IOOutput Sink Current VIN+= 1V,VIN−= 0V, VO= 1.5V 6 13 mA
ILEAKAGE Output Leakage Current VIN+= 1V,VIN−= 0V, VO= 5V 0.1 nA
VIN+= 1V,VIN−= 0V, VO= 30V 1 µA
VOL Output Voltage Low IO=−4mA, VIN+= 0V,VIN−= 1V 180 400 mV
700
VCM Common-Mode Input Voltage VS= 5V to 30V(3) 0 VS- 1.5V V
Range 0 VS- 2V
AVVoltage Gain VS= 15V, VO= 1.4V to 11.4V, 120 V/mV
RL> = 15kΩconnected to VS
tPHL Propagation Delay Input Overdrive = 5mV 900
(High to Low) RL= 5.1kΩconnected to 5V, CL= 15pF ns
Input Overdrive = 50mV 250
RL= 5.1kΩconnected to 5V, CL= 15pF
tPLH Propagation Delay Input Overdrive = 5mV 940 µs
(Low to High) RL= 5.1kΩconnected to 5V, CL= 15pF
Input Overdrive = 50mV 440 ns
RL= 5.1kΩconnected to 5V, CL= 15pF
(1) All limits are specified by testing or statistical analysis.
(2) Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary
over time and will also depend on the application and configuration. The typical values are not tested and are not specified on shipped
production material.
(3) The input common-mode voltage of either input should not be permitted to go below the negative rail by more than 0.3V. The upper end
of the common-mode voltage range is VS- 1.5V at 25°C.
Copyright © 2001–2013, Texas Instruments Incorporated Submit Documentation Feedback 3
Product Folder Links: LM397
200 400 800 1200 1400 2000
-100
-
50
0
50
10
0
0
2
4
6
8
10
OUTPUT (V)
TIME (ns)
VOD = 50mV VOD = 5mV
OVERDRIVE
VOLTAGE (VOD)
VS = 5V, RPULL-UP = 5.1k: TO VS
CL = 15pF TO GND
INPUT (mV)
200 400 800 1200 1400 2000
-100
-
50
0
50
10
0
0
2
4
6
8
10
OUTPUT (V)
TIME (ns)
VOD = 50mV
VOD = 5mV
OVERDRIVE
VOLTAGE (VOD)
VS = 5V, RPULL-UP = 5.1k: TO VS
CL = 15pF TO GND
INPUT (mV)
0510 15 2
025 30
SUPPLY VOLTAGE (V)
1
1.5
2.5
INPUT OFFSET VOLTAGE (mV)
2
-40°C
85°C
25°C
110 100
0.01
0.1
1
OUTPUT SATURATION VOLTAGE (V)
OUTPUT SINK CURRENT (mA)
-40RC25RC
85RC
0 5 10 15 20 25 30
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
SUPPLY CURRENT (mA)
SUPPLY VOLTAGE (V)
-40°C
25°C
85°C
05 10 15 20 25 30
SUPPLY VOLTAGE (V)
0
2
4
6
8
10
12
14
INPUT BIAS CURRENT (nA)
-40°C
25°C
85°C
LM397
SNOS977D –MAY 2001–REVISED MARCH 2013
www.ti.com
Typical Performance Characteristics
TA= 25°C. Unless otherwise specified.
Supply Current Input Bias Current
vs. vs.
Supply Voltage Supply Current
Figure 3. Figure 4.
Output Saturation Voltage Input Offset Voltage
vs. vs.
Output Sink Current Supply Voltage
Figure 5. Figure 6.
Response Time for Various Input Overdrives – tPHL Response Time for Various Input Overdrives – tPLH
Figure 7. Figure 8.
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VOLTS
VREF
VO
TIME
VIN
VREF
VIN
VO
-
+
V-
RPULL-UP
VS
LM397
www.ti.com
SNOS977D –MAY 2001–REVISED MARCH 2013
APPLICATION NOTES
Basic Comparators
A comparator is quite often used to convert an analog signal to a digital signal. The comparator compares an
input voltage (VIN) at the non-inverting pin to the reference voltage (VREF) at the inverting pin. If VIN is less than
VREF the output (VO) is low (VOL). However, if VIN is greater than VREF, the output voltage (VO) is high (VOH).
Refer to Figure 9.
Figure 9. Basic Comparator
Hysteresis
The basic comparator configuration may oscillate or produce a noisy output if the applied differential input is near
the comparator’s input offset voltage. This tends to occur when the voltage on the input is equal or very close to
the other input voltage. Adding hysteresis can prevent this problem. Hysteresis creates two switching thresholds
(one for the rising input voltage and the other for the falling input voltage). Hysteresis is the voltage difference
between the two switching thresholds. When both inputs are nearly equal, hysteresis causes one input to
effectively move quickly pass the other. Thus, effectively moving the input out of region that oscillation may
occur.
For an inverting configured comparator, hysteresis can be added with a three resistor network and positive
feedback. When input voltage (VIN) at the inverting node is less than non-inverting node (VT), the output is high.
The equivalent circuit for the three resistor network is R1in parallel with R3and in series with R2. The lower
threshold voltage VT1 is calculated by:
VT1 = ((VSR2) / (((R1R3) / (R1+ R3)) + R2)) (1)
When VIN is greater than VT, the output voltage is low. The equivalent circuit for the three resistor network is R2
in parallel with R3and in series with R1. The upper threshold voltage VT2 is calculated by:
VT2 = VS((R2R3) / (R2+ R3)) / (R1+ ((R2R3) / (R2+ R3))) (2)
The hysteresis is defined as
ΔVIN = VT1 – VT2 (3)
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110 100
OUTPUT SINK CURRENT (mA)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
OUTPUT SATURATION VOLTAGE (V)
85°C
25°C
-40°C
VO
0VIN
VT2 VT1
VO
VIN -
+
R3
VCC
RPULL-UP
VT
R1
R
2
LM397
SNOS977D –MAY 2001–REVISED MARCH 2013
www.ti.com
Figure 10. Inverting Configured Comparator - LM397
Input Stage
The LM397 has a bipolar input stage. The input common mode voltage range is from 0 to (VS– 1.5V).
Output Stage
The LM397 has an open collector grounded-emitter NPN output transistor for the output stage. This requires an
external pull-up resistor connected between the positive supply voltage and the output. The external pull-up
resistor should be high enough resistance so to avoid excessive power dissipation. In addition, the pull-up
resistor should be low enough resistance to enable the comparator to switch with the load circuitry connected.
Because it is an open collector output stage, several comparator outputs can be connected together to create an
OR’ing function output. With an open collector, the output can be used as a simple SPST switch to ground.The
amount of current which the output can sink is approximately 10mA. When the maximum current limit is reached,
the output transistor will saturate and the output will rise rapidly (Figure 11).
Figure 11. Output Saturation Voltage vs. Output Sink Current
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LM397
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SNOS977D –MAY 2001–REVISED MARCH 2013
REVISION HISTORY
Changes from Revision C (March 2013) to Revision D Page
• Changed layout of National Data Sheet to TI format ............................................................................................................ 6
Copyright © 2001–2013, Texas Instruments Incorporated Submit Documentation Feedback 7
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PACKAGE OPTION ADDENDUM
www.ti.com 1-Nov-2013
Addendum-Page 1
PACKAGING INFORMATION
Orderable Device Status
(1)
Package Type Package
Drawing Pins Package
Qty Eco Plan
(2)
Lead/Ball Finish
(6)
MSL Peak Temp
(3)
Op Temp (°C) Device Marking
(4/5)
Samples
LM397MF NRND SOT-23 DBV 5 1000 TBD Call TI Call TI -40 to 85 C397
LM397MF/NOPB ACTIVE SOT-23 DBV 5 1000 Green (RoHS
& no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 C397
LM397MFX/NOPB ACTIVE SOT-23 DBV 5 3000 Green (RoHS
& no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 C397
(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) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(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/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
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
PACKAGE OPTION ADDENDUM
www.ti.com 1-Nov-2013
Addendum-Page 2
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
LM397MF SOT-23 DBV 5 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3
LM397MF/NOPB SOT-23 DBV 5 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3
LM397MFX/NOPB SOT-23 DBV 5 3000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3
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)
LM397MF SOT-23 DBV 5 1000 210.0 185.0 35.0
LM397MF/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0
LM397MFX/NOPB SOT-23 DBV 5 3000 210.0 185.0 35.0
PACKAGE MATERIALS INFORMATION
www.ti.com 23-Sep-2013
Pack Materials-Page 2
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