General Purpose Comparators
Preliminary Technical Data
ADCMP370/ADCMP371
Rev.PrB
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However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
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Tel: 781.329.4700
www.analog.com
Fax: 781.326.8703
2004 Analog Devices, Inc. All rights reserved.
FEATURES
2.25V to 5.5V Operating Voltage Range
Low Power Consumption (2A)
Output Stages
ADCMP370: Open-Drain with High Voltage (22V)
Tolerance
ADCMP371: Push-Pull
10nA Input Bias Current
5nA Input Offset Current
6mV Input Offset Voltage
0V to V
CC
Common Mode Input Range
Specified Over -40C to +125C Temperature Range
5-Lead SC70 Package
APPLICATIONS
Voltage Detectors
Battery Management Systems
A/D Converters
Low Voltage Applications
Battery Powered Electronics
Portable Equipment
GENERAL DESCRIPTION
The ADCMP370/ADCMP371 are general purpose comparators
with input offset voltages of 6mV (max). High performance
over the -40C to +125C temperature range make them
suitable for use in automotive and other thermally harsh
applications, while low power consumption and space efficient
SC70 packaging make them ideal for battery powered portable
equipment.
The ADCMP371 has a push-pull output stage, while the
ADCMP370 has an open-drain output, which can be pulled as
high as 22V through an external resistor.
FUNCTIONAL BLOCK DIAGRAMS
IN+
ADM331
GND
IN-
OUT
V
CC
IN+
V
CC
ADM332
GND
IN-
OUT
V
CC
ADCMP370
ADCMP371
ADCMP370/ADCMP371
Preliminary Technical Data
Rev. PrB | Page 2 of 8
SPECIFICATIONS
(V
CC
=Full Operating Range, T
A
=-40C to +125C, unless otherwise noted.)
Parameter Min
Typ
Max
Units
Test
Conditions/Comments
SUPPLY
V
CC
Operating Voltage Range
2.25
5.5
V
Supply Current
2 5
A
COMMON MODE INPUT RANGE
0
V
CC
V
INPUT OFFSET VOLTAGE
6
mV
INPUT BIAS CURRENT
10
nA
V
CC
= 3.3V
INPUT OFFSET CURRENT
5
150
nA
OUT VOLTAGE LOW
0.3
V
IN+ < IN-, I
SINK
=1.2mA
OUT VOLTAGE HIGH (ADCMP371)
0.8V
CC
V
IN+ > IN-, I
SOURCE
=500A
OUT LEAKAGE CURRENT (ADCMP370)
1
A
IN+ > IN-, OUT=22V
TIMING
Propagation Delay
5
10
s
Input
Overdrive=10mV
1
2
s
Input
Overdrive=100mV
ABSOLUTE MAXIMUM RATINGS
Table 3. T
A
= 25C unless otherwise noted.
Parameter
Rating
V
CC
-0.3V to +6V
IN+, IN-
-0.3V to +6V
OUT (ADCMP370)
-0.3V to +25V
OUT (ADCMP371)
-0.3V to +V
CC
+0.3V
Operating Temperature Range
-40C to +125C
Storage Temperature Range
-65C to +150C
JA
Thermal Impedance, SC70
146C/W
Lead Temperature
Soldering (10 sec)
300C
Vapour Phase (60 sec)
215C
Infrared (15 sec)
220C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only and functional operation of the device at these or
any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Preliminary Technical Data
ADCMP370/ADCMP371
Rev. PrB | Page 3 of 8
PIN CONFIGURATIONS AND FUNCTIONAL DESCRIPTIONS
1
2
3
4
5 V
CC
GND
IN+
OUT
IN-
ADM331/
ADM332
Table 4. Pin Functional Descriptions
Pin No.
Name
Description
1 IN+
Non-Inverting
Input
2 GND
Ground
3 IN-
Inverting
Input
4
OUT
Comparator Output. Open-Drain for ADCMP370. Push-Pull for ADCMP371.
5 V
CC
Power
Supply
ESD CAUTION
`
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the
human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
ADCMP371
ADCMP370/
ADCMP370/ADCMP371
Preliminary Technical Data
Rev. PrB | Page 4 of 8
TYPICAL PERFORMANCE CHARACTERISTICS
Figure 1. Supply Current vs. Supply Voltage Output High
Figure 2. Supply Current vs. Supply Voltage Output Low
Figure 3. Output Voltage vs. Output Current at 5V Supply
Figure 4. Output Voltage vs. Output Current at 2.7V Supply
Figure 5. Input Bias Current vs. Supply Voltage
Figure 6. Response Time vs. Input Overdrives Negative Transition (5V)
Preliminary Technical Data
ADCMP370/ADCMP371
Rev. PrB | Page 5 of 8
Figure 7. Response Time vs. Input Overdrives Positive Transition (5V)
Figure 8. Response Time vs. Input Overdrives Negative Transition(2.7V)
Figure 9. Response Time vs. Input Overdrives Positive Transition(2.7V)
Figure 10. Output Saturation Voltage vs. Output Sink Current
Figure 11. 10kHz Response
ADCMP370/ADCMP371
Preliminary Technical Data
Rev. PrB | Page 6 of 8
APPLICATIONS INFORMATION
BASIC COMPARATOR
In it's most basic configuration, a comparator can be used to
convert an analog input signal to a digital output signal. The
analog signal on IN+ is compared to the voltage on IN- and the
voltage at OUT is either high or low depending on whether IN+
is at a higher or lower potential than IN-, respectively.
The ADCMP370 and ADCMP371 have different digital output
structures. The ADCMP370 has an open-drain output stage
which requires an external resistor to pull OUT to the logic
high voltage level when the output transistor is switched off.
This voltage level can be as high as 22V. The pull-up resistor
should be large enough to avoid excessive power dissipation, but
small enough to switch logic levels reasonably quickly when the
comparator output is connected to other digital circuitry. A
suitable value would be between 1k
and 10k
. The
ADCMP371 has a push-pull output stage which has an internal
PMOS pull-up and therefore doesn't require an external resistor.
Faster switching speeds between low and high rails are possible,
but the logic high level is limited to V
CC
.
V
IN
ADM331
V
REF
OUT
V
CC
V
+
V
REF
V
IN
t
V
+
V
OUT
0V
Figure 12. Basic Comparator and Input and Output Signals
ADDING HYSTERESIS
To prevent oscillations at the output caused by noise or slowly
moving signals passing the switching threshold, positive
feedback can be used to add hysteresis to the differential input.
For the non-inverting configuration, shown in figure 13, two
resistors are used to create different switching thresholds
depending on whether the input signal is increasing or
decreasing in magnitude. When the input voltage is increasing,
the threshold is above V
REF
and when it's decreasing, the
threshold is below V
REF
.
The upper input threshold level is given by:
(
)
2
1
2
1
V
V
REF
IN_HI
R
R
V
R
R
CC
-
+
=
The lower input threshold level is given by:
(
)
2
2
1
V
V
REF
IN_LO
R
R
R
+
=
The hysteresis is the difference between these voltage levels:
2
1
V
V
CC
IN
R
R
=
In the example in figure 13, resistors R1 and R2 are chosen to
give 1V hysteresis about the reference of 2.5V, with V
CC
=5V. It's
important that R
PULL-UP
<<R
LOAD
so that the output high voltage
isn't pulled below V
CC
.
R1=200k
ADM331
OUT
V
CC
=5V
RLOAD
R
PULL-UP
=5k
VIN
IN-
IN+
V
IN_LO
V
IN_HI
VIN
VOUT
VREF=2.5V
R2=1M
=2V
=3V
Figure 13. Non-Inverting Comparator Configuration with Hysteresis
ADCMP370
ADCMP370
Preliminary Technical Data
ADCMP370/ADCMP371
Rev. PrB | Page 7 of 8
With the inverting configuration, the upper and lower switching
thresholds are as follows:
(
)
2
3
||
1
2
V
V
CC
IN_HI
R
R
R
R
+
=
(
)
(
)
3
||
2
1
3
||
2
V
V
CC
IN_LO
R
R
R
R
R
+
=
IN+
V
CC
ADM332
IN-
OUT
V
IN_LO
V
IN_HI
V
IN
V
OUT
=1.67V
=3.33V
R
LOAD
R3=1M
V
CC
=5V
V
IN
R1=1M
R2=1M
V
CC
R2
R1
R3
V
CC
R2
R1
R3
V
IN_HI
V
IN_LO
V
OUT
High:
V
OUT
Low:
Figure 14. Non-Inverting Comparator Configuration with Hysteresis
ADCMP371
ADCMP370/ADCMP371
Preliminary Technical Data
Rev. PrB | Page 8 of 8
OUTLINE DIMENSIONS
0.087 (2.20)
0.071 (1.80)
PIN 1
0.094 (2.40)
0.071 (1.80)
0.051 (1.30)
BSC
0.026 (0.65) BSC
1
3
4
2
0.053 (1.35)
0.045 (1.15)
0.004 (0.10)
0.004 (0.10)
o
8
0.012 (0.30)
0.006 (0.15)
0.004 (0.10)
0.000 (0.00)
0.039 (1.00)
0.031 (0.80)
SEATING
PLANE
0.043 (1.10)
0.031 (0.80)
0.007 (0.18)
0.012 (0.30)
0
o
5
Figure 1. 5-Lead Plastic Surface Mount Package [SC70]
(KS-5)
Dimensions shown in millimeters
ORDERING GUIDE
Model Temperature
Range
Quantity
Package Type
Branding
ADCMP370AKS-R7
-40C to +125C
3k
SC70-5
M1F
ADCMP370AKS-RL
-40C to +125C
10k
SC70-5
M1F
ADCMP371AKS-R7
-40C to +125C
3k
SC70-5
M1G
ADCMP371AKS-RL
-40C to +125C
10k
SC70-5
M1G
2004 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective companies.
Printed in the U.S.A.
PR04745-0-4/04(PrB)
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