19-0115; Rev 6; 4/09
Ultra Low-Power,
Single/Dual-Supply Comparators
_______________General Description
The MAX921–MAX924 single, dual, and quad micro-
power, low-voltage comparators feature the lowest
power consumption available. These comparators draw
less than 4µA supply current over temperature
(MAX921/MAX922), and include an internal 1.182V
±1% voltage reference, programmable hysteresis, and
TTL/CMOS outputs that sink and source current.
Ideal for 3V or 5V single-supply applications, the
MAX921–MAX924 operate from a single +2.5V to +11V
supply (or a ±1.25V to ±5V dual supply), and each
comparator’s input voltage range swings from the
negative supply rail to within 1.3V of the positive
supply.
The MAX921–MAX924’s unique output stage con-
tinuously sources as much as 40mA. And by eliminating
power-supply glitches that commonly occur when com-
parators change logic states, the MAX921–MAX924
minimize parasitic feedback, which makes them easier to
use.
The single MAX921 and dual MAX923 provide a unique
and simple method for adding hysteresis without
feedback and complicated equations, simply by using
the HYST pin and two resistors.
COMPARATORS
PER
PACKAGE
____________________________Features
♦
µMAX
®
Package—Smallest 8-Pin SO
(MAX921/MAX922/MAX923)
♦
Ultra-Low 4µA Max Quiescent Current
Over Extended Temp. Range (MAX921)
♦
Power Supplies:
Single +2.5V to +11V
Dual ±1.25V to ±5.5V
♦
Input Voltage Range Includes Negative Supply
♦
Internal 1.182V ±1% Bandgap Reference
♦
Adjustable Hysteresis
♦
TTL/CMOS-Compatible Outputs
♦
12µs Propagation Delay (10mV Overdrive)
♦
No Switching Crowbar Current
♦
40mA Continuous Source Current
MAX921–MAX924
Ordering Information
PART
MAX921CPA
MAX921CSA
TEMP RANGE
0°C to +70°C
0°C to +70°C
PIN-PACKAGE
8 Plastic DIP
8 SO
MAX921
MAX922
MAX923
MAX924
Yes
No
Yes
Yes
1
2
2
4
Yes
No
Yes
No
8-Pin
DIP/SO/µMAX
8-Pin
DIP/SO/µMAX
8-Pin
DIP/SO/µMAX
16-Pin
DIP/SO/µMAX
MAX921CUA
0°C to +70°C
8 µMAX
MAX921C/D
0°C to +70°C
Dice*
MAX921EPA
-40°C to +85°C
8 Plastic DIP
MAX921ESA
-40°C to +85°C
8 SO
MAX921MJA
-55°C to +125°C
8 CERDIP
Ordering Information continued at end of data sheet.
*Dice are tested at T
A
= +25°C, DC parameters only.
**Contact factory for availability.
INTERNAL 1%
PRECISION
REFERENCE
INTERNAL
HYSTERESIS
PACKAGE
PART
__________Typical Operating Circuit
V
IN
7
V+
3 IN+
OUT 8
4 IN-
________________________Applications
Battery-Powered Systems
Threshold Detectors
Window Comparators
Oscillator Circuits
µMAX is a registered trademark of Maxim Integrated Products, Inc.
5 HYST
6 REF
V-
2
MAX921
GND
1
THRESHOLD DETECTOR
1
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.
Ultra Low-Power,
Single/Dual-Supply Comparators
MAX921–MAX924
ABSOLUTE MAXIMUM RATINGS
V+ to V-, V+ to GND, GND to V-................................-0.3V, +12V
Inputs
Current, IN_+, IN_-, HYST...............................................20mA
Voltage, IN_+, IN_-, HYST................(V+ + 0.3V) to (V- – 0.3V)
Outputs
Current, REF....................................................................20mA
Current, OUT_ .................................................................50mA
Voltage, REF ....................................(V+ + 0.3V) to (V- – 0.3V)
Voltage, OUT_ (MAX921/924) .....(V+ + 0.3V) to (GND – 0.3V)
Voltage OUT_ (MAX922/923)...........(V+ + 0.3V) to (V- – 0.3V)
OUT_ Short-Circuit Duration (V+
≤
5.5V) ...............Continuous
Continuous Power Dissipation (T
A
= +70°C)
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ...727mW
8-Pin SO (derate 5.88mW/°C above +70°C)................471mW
8-Pin µMAX (derate 4.1mW/°C above +70°C) .............330mW
8-Pin CERDIP (derate 8.00mW/°C above +70°C)........640mW
16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)..842mW
16-Pin SO (derate 8.70mW/°C above +70°C) ................696mW
16-Pin CERDIP (derate 10.00mW/°C above +70°C) ......800mW
Operating Temperature Ranges:
MAX92_C_ _ .......................................................0°C to +70°C
MAX92_E_ _.....................................................-40°C to +85°C
MAX92_MJ_ ..................................................-55°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings‘” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS: 5V OPERATION
(V+ = 5V, V- = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
POWER REQUIREMENTS
Supply Voltage Range
(Note 1)
T
A
= +25°C
MAX921,
C/E temp. ranges
HYST = REF
M temp. range
T
A
= +25°C
MAX922
Supply Current
IN+ = IN- + 100mV
C/E temp. ranges
M temp. range
MAX923,
C/E temp. ranges
HYST = REF
M temp. range
T
A
= +25°C
C/E temp. ranges
MAX924
M temp. range
COMPARATOR
Input Offset Voltage
Input Leakage Current (IN-, IN+)
Input Leakage Current (HYST)
Input Common-Mode Voltage Range
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
Voltage Noise
Hysteresis Input Voltage Range
Response Time
V
CM
= 2.5V
IN+ = IN- = 2.5V
MAX921, MAX923
V-
V- to (V+ – 1.3V)
V+ = 2.5V to 11V
100Hz to 100kHz
MAX921, MAX923
T
A
= +25°C, 100pF load
Overdrive = 10mV
Overdrive = 100mV
0.1
0.1
20
REF- 0.05V
12
4
C/E temp. ranges
M temp. range
±0.01
±0.02
V+ – 1.3
1.0
1.0
REF
T
A
= +25°C
3.1
2.5
2.5
11
3.2
4
5
2.5
3.2
4
5
4.5
6
7.5
6.5
8.5
11
±10
±5
±40
mV
nA
nA
V
mV/V
mV/V
µV
RMS
V
µs
µA
V
CONDITIONS
MIN
TYP
MAX
UNITS
5.5
2
_______________________________________________________________________________________
Ultra Low-Power,
Single/Dual-Supply Comparators
ELECTRICAL CHARACTERISTICS: 5V OPERATION (continued)
(V+ = 5V, V- = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
Output High Voltage
MAX92_
MAX922/
MAX923
MAX921/
MAX924
CONDITIONS
C/E temp. ranges: I
OUT
= 17mA;
M temp. range: I
OUT
= 10mA
C/E temp. ranges: I
OUT
= 1.8mA;
M temp. range: I
OUT
= 1.2mA
C/E temp. ranges: I
OUT
= 1.8mA;
M temp. range: I
OUT
= 1.2mA
C temp. range
E temp. range
M temp. range
T
A
= +25°C
C/E temp. ranges
M temp. range
T
A
= +25°C
C/E temp. ranges
M temp. range
100Hz to 100kHz
1.170
1.158
1.147
15
6
4
8
4
2
MIN
V+ – 0.4
V- + 0.4
V
GND + 0.4
TYP
MAX
UNITS
V
MAX921–MAX924
Output Low Voltage
REFERENCE
(MAX921/MAX923/MAX924 ONLY)
X
1.182
Reference Voltage
1.194
1.206
1.217
V
25
µA
15
µA
100
µV
RMS
Source Current
Sink Current
Voltage Noise
Note 1:
MAX924 comparators work below 2.5V, see
Low-Voltage Operation
section for more details.
ELECTRICAL CHARACTERISTICS: 3V OPERATION
(V+ = 3V, V- = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
POWER REQUIREMENTS
T
A
= +25°C
MAX921
C/E temp. ranges
M temp. range
T
A
= +25°C
MAX922
Supply Current
HYST = REF,
IN+ = (IN- + 100mV)
MAX923
C/E temp. ranges
M temp. range
T
A
= +25°C
C/E temp. ranges
M temp. range
T
A
= +25°C
C/E temp. ranges
M temp. range
3.4
2.4
2.4
3.0
3.8
4.8
3.0
3.8
4.8
4.3
5.8
7.2
6.2
8.0
10.5
±10
±5
±40
mV
nA
nA
µA
CONDITIONS
MIN
TYP
MAX
UNITS
5.2
MAX924
COMPARATOR
Input Offset Voltage
Input Leakage Current (IN-, IN+)
Input Leakage Current (HYST)
V
CM
= 1.5V
IN+ = IN- = 1.5V
MAX921, MAX923
C/E temp. ranges
M temp. range
±0.01
±0.02
_______________________________________________________________________________________
3
Ultra Low-Power,
Single/Dual-Supply Comparators
MAX921–MAX924
ELECTRICAL CHARACTERISTICS: 3V OPERATION (continued)
(V+ = 3V, V- = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
Input Common-Mode Voltage Range
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
Voltage Noise
Hysteresis Input Voltage Range
Response Time
Output High Voltage
CONDITIONS
V- to (V+ – 1.3V)
V+ = 2.5V to 11V
100Hz to 100kHz
MAX921, MAX923
T
A
= +25°C, 100pF load
MAX92_
MAX922/
MAX923
MAX921/
MAX924
Overdrive = 10mV
Overdrive = 100mV
V+ – 0.4
V- + 0.4
V
GND + 0.4
MIN
V-
0.2
0.1
20
REF- 0.05V
14
5
TYP
MAX
V+ – 1.3
1
1
REF
UNITS
V
mV/V
mV/V
µV
RMS
V
µs
V
C/E temp. ranges: I
OUT
= 10mA;
M temp. range: I
OUT
= 6mA
C/E temp. ranges: I
OUT
= 0.8mA;
M temp. range: I
OUT
= 0.6mA
C/E temp. ranges: I
OUT
= 0.8mA;
M temp. range: I
OUT
= 0.6mA
C temp. range
E temp. range
M temp. range
T
A
= +25°C
C/E temp. ranges
M temp. range
T
A
= +25°C
C/E temp. ranges
M temp. range
Output Low Voltage
REFERENCE
Reference Voltage
1.170
1.158
1.147
15
6
4
8
4
2
1.182
1.194
1.206
1.217
V
25
µA
15
µA
100
µV
RMS
Source Current
Sink Current
Voltage Noise
100Hz to 100kHz
Typical Operating Characteristics
(V+ = 5V, V- = GND, T
A
= +25°C, unless otherwise noted).
OUTPUT VOLTAGE LOW
vs. LOAD CURRENT
MAX921/4-TOC1
OUTPUT VOLTAGE HIGH vs.
LOAD CURRENT
MAX921/924-TOC2
REFERENCE OUTPUT VOLTAGE vs.
OUTPUT LOAD CURRENT
REFERENCE OUTPUT VOLTAGE (V)
SINK
1.185
1.180
SOURCE
1.175
1.170
1.165
1.160
1.155
V+ = 5V
OR
V+ = 3V
0
5
10
15
20
25
30
MAX921/924-TOC3
2.5
V+ = 5V
5.0
4.5
4.0
V
OH
(V)
3.5
3.0
2.5
V+ = 5V
1.190
2.0
V+ = 3V
V
OL
(V)
1.5
1.0
0.5
2.0
0.0
0
4
8
12
16
20
LOAD CURRENT (mA)
1.5
0
10
20
30
V+ = 3V
40
50
LOAD CURRENT (mA)
OUTPUT LOAD CURRENT (μA)
4
_______________________________________________________________________________________
Ultra Low-Power,
Single/Dual-Supply Comparators
MAX921-MAX924
Typical Operating Characteristics (continued)
(V+ = 5V, V- = GND, T
A
= +25°C, unless otherwise noted).
REFERENCE VOLTAGE
vs. TEMPERATURE
MAX921/924-TOC4
MAX921
SUPPLY CURRENT vs.
TEMPERATURE
MAX921/924-TOC5
MAX922
SUPPLY CURRENT vs. TEMPERATURE
IN+ = (IN- + 100mV)
4.0
SUPPLY CURRENT (μA)
3.5
V+ = 10V, V- = 0V
3.0
2.5
V+ = 5V, V- = 0V
2.0
V+ = 3V, V- = 0V
1.5
MAX921/924-TOC6
1.22
1.21
REFERENCE VOLTAGE (V)
1.20
1.19
1.18
1.17
1.16
1.15
MILITARY TEMP. RANGE
EXTENDED TEMP. RANGE
COMMERCIAL
TEMP. RANGE
4.5
IN+ = (IN- + 100mV)
SUPPLY CURRENT (μA)
4.0
V+ = 5V, V- = - 5V
4.5
3.5
3.0
V+ = 3V, V- = 0V
2.5
V+ = 5V, V- = 0V
1.14
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
2.0
-60
-20
20
60
100
140
TEMPERATURE (°C)
-60
-20
20
60
100
140
TEMPERATURE (°C)
MAX923
SUPPLY CURRENT vs. TEMPERATURE
MAX921/924-TOC7
MAX924
SUPPLY CURRENT vs. TEMPERATURE
MAX921/924-TOC8
MAX924
SUPPLY CURRENT vs.
LOW SUPPLY VOLTAGES
MAX921/924-TOC9
5.0
4.5
SUPPLY CURRENT (μA)
4.0
V+ = 5V, V- = 0V
3.5
3.0
2.5
V+ = 3V, V- = 0V
2.0
-60
-20
20
60
100
10
IN+ = (IN- + 100mV)
9
SUPPLY CURRENT (μA)
8
7
6
5
4
3
V+ = 5V, V- = 0V
V+ = 3V, V- = 0V
V+ = 5V, V- = -5V
10
SUPPLY CURRENT (μA)
140
1
0.1
0.01
-60
-20
20
60
100
1.0
1.5
2.0
2.5
TEMPERATURE (°C)
SINGLE-SUPPLY VOLTAGE (V)
140
TEMPERATURE (°C)
HYSTERESIS CONTROL
MAX921/924 TOC10
TRANSFER FUNCTION
MAX921/924-TOC11
RESPONSE TIME vs.
LOAD CAPACITANCE
16
RESPONSE TIME (μs)
14
12
10
8
6
4
2
V
OLH
V- = 0V
MAX921/924 TOC12
80
60
OUTPUT HIGH
40
IN+ – IN- (mV)
20
0
-20
-40
-60
-80
0
10
20
30
40
OUTPUT LOW
NO CHANGE
5.0
4.5
4.0
OUTPUT VOLTAGE (V)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
100k
10μF
V
0
18
V
OHL
50
-0.3
V
REF
-V
HYST
(mV)
0.2
0.1
-0.2 -0.1
0
IN+ INPUT VOLTAGE (mV)
0.3
0
20
40
60
80
100
LOAD CAPACITANCE (nF)
_______________________________________________________________________________________
5
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