TI LM397

LM397
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SNOS977D – MAY 2001 – REVISED MARCH 2013
LM397 Single General Purpose Voltage Comparator
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FEATURES
DESCRIPTION
•
The LM397 is a single voltage comparator with an
input common mode that includes ground. The
LM397 is designed to operate from a single 5V to
30V power supply or a split power supply. Its low
supply current is virtually independent of the
magnitude of the supply voltage.
1
2
•
•
•
•
•
•
•
•
•
•
(TA = 25°C. Typical Values Unless Otherwise
Specified).
5-Pin SOT-23 Package
Industrial Operating Range −40°C to +85°C
Single or Dual Power Supplies
Wide Supply Voltage Range 5V to 30V
Low Supply Current 300µA
Low Input Bias Current 7nA
Low Input Offset Current ±1nA
Low Input Offset Voltage ±2mV
Response Time 440ns (50mV Overdrive)
Input Common Mode Voltage 0 to VS - 1.5V
The LM397 features an open collector output stage.
This allows the connection of an external resistor at
the output. The output can directly interface with TTL,
CMOS and other logic levels, by tying the resistor to
different voltage levels (level translator).
The LM397 is available in space saving 5-Pin SOT23 package and pin compatible to TI’s TL331, single
differential comparator.
APPLICATIONS
•
•
•
•
A/D Converters
Pulse, Square Wave Generators
Peak Detector
Industrial Applications
Typical Circuit
Connection Diagram
VS
Top View
VIN
-
1
5
VS
R1
2
+
3
RPULL-UP
-
VO
+
GND
VIN
VIN
4
OUTPUT
R3
R2
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.
1
2
Please 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.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2001–2013, Texas Instruments Incorporated
LM397
SNOS977D – MAY 2001 – REVISED MARCH 2013
www.ti.com
Absolute Maximum Ratings (1) (2)
ESD Tolerance (3)
Human Body Model
Machine Model
VIN Differential
30V
Supply Voltages
30V or ±15V
−0.3V to 30V
Voltage at Input Pins
−65°C to +150°C
Storage Temperature Range
Junction Temperature (4)
Soldering Information
(1)
(2)
(3)
(4)
2KV
200V
+150°C
Infrared or Convection (20 sec.)
235°C
Wave Soldering (10 sec.)
260°C
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.
If Military/Aerospace specified devices are required, please contact the TI Sales Office/ Distributors for availability and specifications.
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).
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, VS
5V to 30V
Temperature Range (2)
Package Thermal Resistance (2)
(1)
(2)
2
−40°C to +85°C
5-Pin SOT-23
168°C/W
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.
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,
VO = 1.4V, VCM = 0V
2
7
10
mV
IOS
Input Offset Current
VO = 1.4V, VCM = 0V
1.6
50
250
nA
IB
Input Bias Current
VO = 1.4V, VCM = 0V
10
250
400
nA
IS
Supply Current
RL = Open, VS = 5V
0.25
0.7
RL = Open, VS = 30V
0.30
2
6
mA
IO
Output Sink Current
VIN+ = 1V,VIN− = 0V, VO = 1.5V
ILEAKAGE
Output Leakage Current
VIN+ = 1V,VIN− = 0V, VO = 5V
0.1
13
mA
nA
VIN+ = 1V,VIN− = 0V, VO = 30V
1
µA
180
VOL
Output Voltage Low
IO = −4mA, VIN+ = 0V,VIN− = 1V
VCM
Common-Mode Input Voltage
Range
VS = 5V to 30V (3)
AV
Voltage Gain
VS = 15V, VO = 1.4V to 11.4V,
RL > = 15kΩ connected to VS
120
tPHL
Propagation Delay
(High to Low)
Input Overdrive = 5mV
RL = 5.1kΩ connected to 5V, CL = 15pF
900
Input Overdrive = 50mV
RL = 5.1kΩ connected to 5V, CL = 15pF
250
Input Overdrive = 5mV
RL = 5.1kΩ connected to 5V, CL = 15pF
940
µs
Input Overdrive = 50mV
RL = 5.1kΩ connected to 5V, CL = 15pF
440
ns
tPLH
(1)
(2)
(3)
Propagation Delay
(Low to High)
0
0
400
700
mV
VS - 1.5V
VS - 2V
V
V/mV
ns
All limits are specified by testing or statistical analysis.
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.
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.
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LM397
SNOS977D – MAY 2001 – REVISED MARCH 2013
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Typical Performance Characteristics
TA = 25°C. Unless otherwise specified.
Supply Current
vs.
Supply Voltage
Input Bias Current
vs.
Supply Current
14
0.45
-40°C
0.35
INPUT BIAS CURRENT (nA)
SUPPLY CURRENT (mA)
0.4
25°C
0.3
85°C
0.25
0.2
0.15
0.1
0
5
10
15
25
20
SUPPLY VOLTAGE (V)
6
4
0
30
5
0
Output Saturation Voltage
vs.
Output Sink Current
Input Offset Voltage
vs.
Supply Voltage
0.1
30
2.5
R
-40°C
-40 C
R
25 C
R
85 C
85°C
2
25°C
1.5
1
0.01
1
10
20
25
15
SUPPLY VOLTAGE (V)
Figure 4.
INPUT OFFSET VOLTAGE (mV)
OUTPUT SATURATION VOLTAGE (V)
85°C
8
Figure 3.
1
10
OUTPUT SINK CURRENT (mA)
0
100
5
2
15
25
10
0
SUPPLY VOLTAGE (V)
30
Figure 5.
Figure 6.
Response Time for Various Input Overdrives – tPHL
Response Time for Various Input Overdrives – tPLH
6
10
VS = 5V, RPULL-UP = 5.1k: TO VS
CL = 15pF TO GND
4
VOD = 5mV
2
INPUT (mV)
OUTPUT (V)
8
0
10
0
50
VOD = 50mV
0
50
-100
200
OVERDRIVE
VOLTAGE (VOD)
400
800
1200
1400
8
6
2000
VS = 5V, RPULL-UP = 5.1k: TO VS
CL = 15pF TO GND
4
2
INPUT (mV)
OUTPUT (V)
10
4
25°C
10
2
0.05
0
-40°C
12
VOD = 50mV
0
10
0
50
VOD = 5mV
0
50
-100
200
OVERDRIVE
VOLTAGE (VOD)
400
800
1200
TIME (ns)
TIME (ns)
Figure 7.
Figure 8.
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1400
2000
Copyright © 2001–2013, Texas Instruments Incorporated
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LM397
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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.
VS
VREF
-
VIN
+
RPULL-UP
VO
V
-
VOLTS
VO
VREF
TIME
VIN
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 R1 in parallel with R3 and in series with R2. The lower
threshold voltage VT1 is calculated by:
VT1 = ((VS R2) / (((R1 R3) / (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 R3 and in series with R1. The upper threshold voltage VT2 is calculated by:
VT2 = VS ((R2 R3) / (R2 + R3)) / (R1 + ((R2 R3) / (R2 + R3)))
(2)
The hysteresis is defined as
ΔVIN = VT1 – VT2
(3)
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LM397
SNOS977D – MAY 2001 – REVISED MARCH 2013
www.ti.com
VCC
VIN
R1
RPULL-UP
-
VO
VT
+
R
R3
2
VO
VT1
VT2
0
VIN
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).
OUTPUT SATURATION VOLTAGE (V)
5
-40°C
4.5
85°C
4
3.5
25°C
3
2.5
2
1.5
1
0.5
0
1
10
OUTPUT SINK CURRENT (mA)
100
Figure 11. Output Saturation Voltage vs. Output Sink Current
6
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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
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PACKAGE OPTION ADDENDUM
www.ti.com
1-Nov-2013
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
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
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
1-Nov-2013
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.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
23-Sep-2013
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
LM397MF
SOT-23
DBV
5
1000
178.0
8.4
LM397MF/NOPB
SOT-23
DBV
5
1000
178.0
LM397MFX/NOPB
SOT-23
DBV
5
3000
178.0
3.2
3.2
1.4
4.0
8.0
Q3
8.4
3.2
3.2
1.4
4.0
8.0
Q3
8.4
3.2
3.2
1.4
4.0
8.0
Q3
Pack Materials-Page 1
W
Pin1
(mm) Quadrant
PACKAGE MATERIALS INFORMATION
www.ti.com
23-Sep-2013
*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
Pack Materials-Page 2
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