_______________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.
________________________Applications
Battery-Powered Systems
Threshold Detectors
Window Comparators
Oscillator Circuits
____________________________Features
o
µMAX Package—Smallest 8-Pin SO
(MAX921/MAX922/MAX923)
o
Ultra-Low 4µA Max Quiescent Current
Over Extended Temp. Range (MAX921)
o
Power Supplies:
Single +2.5V to +11V
Dual ±1.25V to ±5.5V
o
Input Voltage Range Includes Negative Supply
o
Internal 1.182V ±1% Bandgap Reference
o
Adjustable Hysteresis
o
TTL/CMOS-Compatible Outputs
o
12µs Propagation Delay (10mV Overdrive)
o
No Switching Crowbar Current
o
40mA Continuous Source Current
______________Ordering Information
Ordering Information continued at end of data sheet.
*
Dice are tested at T
A
= +25°C, DC parameters only.
** Contact factory for availability and processing to MIL-STD-883.
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
________________________________________________________________
Maxim Integrated Products
1
MAX921
OUT
IN+
HYST
REF
V-
GND
V+
2
1
4
5
6
8
3
7
IN-
THRESHOLD DETECTOR
V
IN
__________Typical Operating Circuit
Call toll free 1-800-998-8800 for free samples or literature.
19-0115; Rev 3; 3/95
PART
TEMP. RANGE
PIN-PACKAGE
MAX921
CPA
0°C to +70°C
8 Plastic DIP
MAX921CSA
0°C to +70°C
8 SO
MAX921C/D
0°C to +70°C
Dice*
PART
INTERNAL 1%
PRECISION
REFERENCE
COMPARATORS
PER
PACKAGE
INTERNAL
HYSTERESIS
PACKAGE
MAX921
Yes
1
Yes
8-Pin
DIP/SO/µMAX
MAX922
No
2
No
8-Pin
DIP/SO/µMAX
MAX923
Yes
2
Yes
8-Pin
DIP/SO/µMAX
MAX924
Yes
4
No
16-Pin
DIP/SO/µMAX
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**
MAX921CUA
0°C to +70°C
8 µMAX
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
2
_______________________________________________________________________________________
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, 10sec) .............................+300°C
ELECTRICAL CHARACTERISTICS: 5V OPERATION
(V+ = 5V, V- = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
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.
PARAMETER
MAX923,
HYST = REF
MIN TYP MAX
UNITS
MAX924
7.5
V
V-
V+ – 1.3
5.5
6.5
MAX921,
HYST = REF
8.5
Supply Current
IN+ = IN- + 100mV
IN+ = IN- = 2.5V
11
µA
Supply Voltage Range
T
A
= +25°C, 100pF load
2.5
11
V
2.5
3.2
MAX922
4
5
2.5
3.2
Input Offset Voltage
CONDITIONS
M temp. range
±10
mV
T
A
= +25°C
C/E temp. ranges
M temp. range
±0.01
±5
nA
Input Leakage Current (IN-, IN+)
(Note 1)
±40
Input Leakage Current (HYST)
T
A
= +25°C
C/E temp. ranges
M temp. range
±0.02
nA
Input Common-Mode Voltage Range
T
A
= +25°C
V
CM
= 2.5V
C/E temp. ranges
Common-Mode Rejection Ratio
M temp. range
MAX921, MAX923
0.1
1.0
mV/V
Power-Supply Rejection Ratio
V- to (V+ – 1.3V)
V+ = 2.5V to 11V
100Hz to 100kHz
0.1
1.0
mV/V
Voltage Noise
MAX921, MAX923
Overdrive = 10mV
Overdrive = 100mV
20
µV
RMS
Hysteresis Input Voltage Range
REF- 0.05V
REF
V
C/E temp. ranges
M temp. range
T
A
= +25°C
12
µs
Response Time
C/E temp. ranges
4
4
5
3.1
4.5
6
POWER REQUIREMENTS
COMPARATOR
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
_______________________________________________________________________________________
3
PARAMETER
Voltage Noise
C/E temp. ranges: I
OUT
= 17mA;
M temp. range: I
OUT
= 10mA
MIN TYP MAX
UNITS
100Hz to 100kHz
100
µV
RMS
MAX922/
MAX923
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
CONDITIONS
C temp. range
V
Output High Voltage
E temp. range
MAX92_
M temp. range
V+ – 0.4
T
A
= +25°C
V- + 0.4
V
15
25
µA
C/E temp. ranges
6
Source Current
M temp. range
4
T
A
= +25°C
GND + 0.4
Output Low Voltage
8
15
MAX921/
MAX924
µA
X
C/E temp. ranges
4
Sink Current
1.170
1.182
1.194
V
M temp. range
1.158
1.206
Reference Voltage
2
1.147
1.217
ELECTRICAL CHARACTERISTICS: 5V OPERATION (continued)
(V+ = 5V, V- = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS: 3V OPERATION
(V+ = 3V, V- = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
MAX923
MIN TYP MAX
UNITS
MAX924
7.2
5.2
6.2
MAX921
8.0
Supply Current
HYST = REF,
IN+ = (IN- + 100mV)
IN+ = IN- = 1.5V
10.5
µA
2.4
3.0
MAX922
3.8
4.8
2.4
3.0
Input Offset Voltage
CONDITIONS
M temp. range
±10
mV
T
A
= +25°C
C/E temp. ranges
M temp. range
±0.01
±5
nA
Input Leakage Current (IN-, IN+)
±40
Input Leakage Current (HYST)
T
A
= +25°C
C/E temp. ranges
M temp. range
±0.02
nA
T
A
= +25°C
V
CM
= 1.5V
C/E temp. ranges
M temp. range
MAX921, MAX923
C/E temp. ranges
M temp. range
T
A
= +25°C
C/E temp. ranges
3.8
4.8
3.4
4.3
5.8
REFERENCE
(MAX921/MAX923/MAX924 ONLY)
POWER REQUIREMENTS
COMPARATOR
Note 1:
MAX924 comparators work below 2.5V, see
Low-Voltage Operation section for more details.
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
4
_______________________________________________________________________________________
__________________________________________Typical Operating Characteristics
(V+ = 5V, V- = GND, T
A
= +25°C, unless otherwise noted).
0.0
0
20
OUTPUT VOLTAGE LOW
vs. LOAD CURRENT
0.5
2.5
MAX921/4-TOC1
LOAD CURRENT (mA)
V
OL
(V)
12
1.5
1.0
4
8
16
2.0
V+ = 5V
V+ = 3V
1.5
0
10
30
50
OUTPUT VOLTAGE HIGH vs.
LOAD CURRENT
2.5
4.5
MAX921/924-TOC2
LOAD CURRENT (mA)
V
OH
(V)
20
40
3.5
5.0
2.0
4.0
3.0
V+ = 5V
V+ = 3V
1.155
0
5
15
25
REFERENCE OUTPUT VOLTAGE vs.
OUTPUT LOAD CURRENT
1.165
1.185
MAX921/924-TOC3
OUTPUT LOAD CURRENT (
µ
A)
REFERENCE OUTPUT VOLTAGE (V)
10
20
1.175
1.190
1.160
1.180
1.170
V+ = 5V
OR
V+ = 3V
30
SINK
SOURCE
ELECTRICAL CHARACTERISTICS: 3V OPERATION (continued)
(V+ = 3V, V- = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
Voltage Noise
C/E temp. ranges: I
OUT
= 10mA;
M temp. range: I
OUT
= 6mA
MIN TYP MAX
UNITS
100Hz to 100kHz
100
µV
RMS
Input Common-Mode Voltage Range
V
V-
V+ – 1.3
MAX922/
MAX923
T
A
= +25°C, 100pF load
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
CONDITIONS
Common-Mode Rejection Ratio
0.2
1
mV/V
Power-Supply Rejection Ratio
V- to (V+ – 1.3V)
V+ = 2.5V to 11V
100Hz to 100kHz
0.1
1
mV/V
Voltage Noise
MAX921, MAX923
Overdrive = 10mV
Overdrive = 100mV
20
µV
RMS
Hysteresis Input Voltage Range
REF- 0.05V
REF
V
14
µs
Response Time
5
C temp. range
V
Output High Voltage
E temp. range
MAX92_
M temp. range
V+ – 0.4
T
A
= +25°C
V- + 0.4
V
15
25
µA
C/E temp. ranges
6
Source Current
M temp. range
4
T
A
= +25°C
GND + 0.4
Output Low Voltage
8
15
MAX921/
MAX924
µA
C/E temp. ranges
4
Sink Current
1.170
1.182
1.194
V
M temp. range
1.158
1.206
Reference Voltage
2
1.147
1.217
REFERENCE
MAX921-MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
_______________________________________________________________________________________
5
1.22
1.14
-60
-20
60
140
REFERENCE VOLTAGE
vs. TEMPERATURE
1.16
1.20
MAX921/924-TOC4
TEMPERATURE (
°
C)
REFERENCE VOLTAGE (V)
20
100
1.18
1.21
1.15
1.19
1.17
-40
0
80
40
120
MILITARY TEMP. RANGE
EXTENDED TEMP. RANGE
COMMERCIAL
TEMP. RANGE
2.0
-60
140
MAX921
SUPPLY CURRENT vs.
TEMPERATURE
2.5
4.5
MAX921/924-TOC5
TEMPERATURE (
°
C)
SUPPLY CURRENT (
µ
A)
60
3.5
3.0
-20
20
100
4.0
V+ = 5V, V- = - 5V
V+ = 3V, V- = 0V
V+ = 5V, V- = 0V
IN+ = IN- + 100mV
4.5
1.5
-60
140
MAX922
SUPPLY CURRENT vs. TEMPERATURE
2.0
4.0
MAX921/924-TOC6
TEMPERATURE (
°
C)
SUPPLY CURRENT (
µ
A)
60
3.0
2.5
-20
20
100
3.5
IN+ = (IN- + 100mV)
V+ = 5V, V- = 0V
V+ = 3V, V- = 0V
V+ = 10V, V- = 0V
4.5
5.0
-60
140
MAX923
SUPPLY CURRENT vs. TEMPERATURE
2.0
4.0
MAX921/924-TOC7
TEMPERATURE (
°
C)
SUPPLY CURRENT (
µ
A)
60
3.0
2.5
-20
20
100
3.5
V+ = 5V, V- = 0V
V+ = 3V, V- = 0V
80
-80
0
10
30
50
HYSTERESIS CONTROL
-40
40
MAX921/924 TOC10
V
REF
-V
HYST
(mV)
IN+ – IN- (V)
20
40
0
60
-60
20
-20
NO CHANGE
OUTPUT LOW
OUTPUT HIGH
10
3
-60
140
MAX924
SUPPLY CURRENT vs. TEMPERATURE
4
8
MAX921/924-TOC8
TEMPERATURE (
°
C)
SUPPLY CURRENT (
µ
A)
60
6
5
-20
20
100
7
9
IN+ = (IN- + 100mV)
V+ = 5V, V- = 0V
V+ = 3V, V- = 0V
V+ = 5V, V- = -5V
10
0.01
1.0
2.0
2.5
MAX924
SUPPLY CURRENT vs.
LOW SUPPLY VOLTAGES
0.1
1
MAX921/924-TOC9
SINGLE-SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
µ
A)
1.5
5.0
0
-0.3
-0.1
0.3
TRANSFER FUNCTION
1.0
4.0
MAX921/924-TOC11
IN+ INPUT VOLTAGE (mV)
OUTPUT VOLTAGE (V)
0.1
3.0
2.0
4.5
0.5
3.5
2.5
1.5
-0.2
0
0.2
100k
V
0
10
µ
F
18
2
0
20
60
100
RESPONSE TIME vs.
LOAD CAPACITANCE
6
14
MAX921/924 TOC12
LOAD CAPACITANCE (nF)
RESPONSE TIME (
µ
s)
40
80
10
16
4
12
8
V
OLH
V- = 0V
V
OHL
__________________________________________Typical Operating Characteristics
(V+ = 5V, V- = GND, T
A
= +25°C, unless otherwise noted).
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
6
_______________________________________________________________________________________
__________________________________________Typical Operating Characteristics
(V+ = 5V, V- = GND, T
A
= +25°C, unless otherwise noted).
-2
2
10
18
RESPONSE TIME FOR VARIOUS
INPUT OVERDRIVES
0
4
MAX921/924-TOC13
RESPONSE TIME (
µ
s)
OUTPUT VOLTAGE (V)
6
14
2
0
5
100
3
1
50mV
100mV
20mV
10mV
INPUT VOLTAGE (mV)
-2
2
10
18
RESPONSE TIME FOR VARIOUS
INPUT OVERDRIVES
0
4
MAX921/924-TOC14
RESPONSE TIME (
µ
s)
OUTPUT VOLTAGE (V)
6
14
2
0
5
100
3
1
50mV
100mV
20mV
10mV
INPUT VOLTAGE (mV)
10
0.01
1.0
2.0
2.5
MAX924 RESPONSE TIME
AT LOW SUPPLY VOLTAGES
0.1
1
MAX921/924-TOC15
SINGLE-SUPPLY VOLTAGE (V)
RESPONSE TIME (ms)
1.5
±
20mV OVERDRIVE
±
100mV
OVERDRIVE
100
0.1
1.0
2.0
2.5
MAX924 RESPONSE TIME
AT LOW SUPPLY VOLTAGES
1
10
MAX921/924-TOC16
SINGLE-SUPPLY VOLTAGE (V)
CURRENT (mA)
1.5
SINK CURRENT AT V
OUT
= 0.4V
SOURCE CURRENT INTO 0.75V LOAD
200
0
0
1.0
3.0
5.0
SHORT-CIRCUIT SOURCE CURRENT
vs. SUPPLY VOLTAGE
40
160
MAX121/124-TOC17
TOTAL SUPPLY VOLTAGE (V)
SOURCE CURRENT (mA)
2.0
4.0
120
80
20
60
180
140
100
OUT CONNECTED TO V-
20
0
0
10
SHORT-CIRCUIT SINK CURRENT
vs. SUPPLY VOLTAGE
MAX121/124-TOC18
TOTAL SUPPLY VOLTAGE (V)
SINK CURRENT (mA)
5
10
OUT CONNECTED TO V+
GND CONNECTED TO V-
PIN
MAX921
MAX922
MAX923
NAME
FUNCTION
1
–
–
GND
Ground. Connect to V- for single-supply operation. Output swings from V+ to GND.
–
1
OUTA
Comparator A output. Sinks and sources current. Swings from V+ to V-.
2
2
2
V-
Negative supply. Connect to ground for single-supply operation (MAX921).
1
3
–
–
IN+
Noninverting comparator input
–
3
3
INA+
Noninverting input of comparator A
4
–
–
IN-
Inverting comparator input
____________________________________________________________Pin Descriptions
–
4
–
INA-
Inverting input of comparator A
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
_______________________________________________________________________________________
7
PIN
–
–
6
–
MAX921
MAX922
MAX923
NAME
FUNCTION
–
5
4
INB-
Inverting input of comparator B
INB+
5
5
HYST
Hysteresis input. Connect to REF if not used. Input voltage range is from
V
REF
to V
REF
- 50mV.
6
–
6
REF
Reference output. 1.182V with respect to V-.
Noninverting input of comparator B
7
7
7
V+
Positive supply
8
–
–
OUT
Comparator output. Sinks and sources current. Swings from V+ to GND.
–
8
8
OUTB
Comparator B output. Sinks and sources current. Swings from V+ to V-.
_______________________________________________Pin Descriptions (continued)
PIN
MAX924
NAME
FUNCTION
1
OUTB
Comparator B output. Sinks and sources current. Swings from V+ to GND.
2
OUTA
Comparator A output. Sinks and sources current. Swings from V+ to GND.
3
V+
Positive supply
4
INA-
Inverting input of comparator A
5
INA+
Noninverting input of comparator A
6
INB-
Inverting input of comparator B
7
INB+
Noninverting input of comparator B
8
REF
Reference output. 1.182V with respect to V-.
9
V-
Negative supply. Connect to ground for single-supply operation.
10
INC-
Inverting input of comparator C
11
INC+
Noninverting input of comparator C
12
IND-
Inverting input of comparator D
13
IND+
Noninverting input of comparator D
14
GND
Ground. Connect to V- for single-supply operation.
15
OUTD
Comparator D output. Sinks and sources current. Swings from V+ to GND.
16
OUTC
Comparator C output. Sinks and sources current. Swings from V+ to GND.
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
8
_______________________________________________________________________________________
_______________Detailed Description
The MAX921–MAX924 comprise various combinations
of a micropower 1.182V reference and a micropower
comparator. The
Typical Operating Circuit shows the
MAX921 configuration, and Figures 1a-1c show the
MAX922–MAX924 configurations.
Each comparator continuously sources up to 40mA,
and the unique output stage eliminates crowbar
glitches during output transitions. This makes them
immune to parasitic feedback (which can cause
instability) and provides excellent performance, even
when circuit-board layout is not optimal.
Internal hysteresis in the MAX921 and MAX923 provides