MAXIM MAX921, MAX924 Technical data

_______________General Description

The MAX921–MAX924 single, dual, and quad micro­power, 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 con­tinuously sources as much as 40mA. And by eliminating
power-supply glitches that commonly occur when com­parators 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

♦ 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

Ordering Information continued at end of data sheet.

*Dice are tested at T

A

= +25°C, DC parameters only.

**Contact factory for availability.

MAX921–MAX924

Ultra Low-Power,

Single/Dual-Supply Comparators

________________________________________________________________ Maxim Integrated Products 1

MAX921

OUT

IN+

HYST

REF

V-

GND

V+

21

4

5

6

8

3

7

IN-

THRESHOLD DETECTOR

V

IN

__________Typical Operating Circuit

19-0115; Rev 6; 4/09

PART TEMP RANGE PIN-PACKAGE

MAX921CPA

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

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.

Ordering Information

µMAX is a registered trademark of Maxim Integrated Products, Inc.

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 (TA= +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

ELECTRICAL CHARACTERISTICS: 5V OPERATION

(V+ = 5V, V- = GND = 0V, TA= 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

VV- 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

TA= +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

TA= +25°C

C/E temp. ranges

M temp. range

±0.01 ±5

nAInput Leakage Current (IN-, IN+)

(Note 1)

±40

Input Leakage Current (HYST)

TA= +25°C

C/E temp. ranges

M temp. range

±0.02 nA

Input Common-Mode Voltage Range

TA= +25°C

VCM= 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

TA= +25°C

12

µsResponse 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

VOutput High Voltage

E temp. range

MAX92_

M temp. range

V+ – 0.4

TA= +25°C

V- + 0.4

V

15 25

µAC/E temp. ranges 6Source Current

M temp. range 4

TA= +25°C

GND + 0.4

Output Low Voltage

815

MAX921/
MAX924

µA

X

C/E temp. ranges 4

Sink Current

1.170 1.182 1.194

V

M temp. range

1.158 1.206Reference Voltage

2

1.147 1.217

ELECTRICAL CHARACTERISTICS: 5V OPERATION (continued)

(V+ = 5V, V- = GND = 0V, TA= T

MIN

to T

MAX

, unless otherwise noted.)

ELECTRICAL CHARACTERISTICS: 3V OPERATION

(V+ = 3V, V- = GND = 0V, TA= 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

TA= +25°C

C/E temp. ranges

M temp. range

±0.01 ±5

nAInput Leakage Current (IN-, IN+)

±40

Input Leakage Current (HYST)

TA= +25°C

C/E temp. ranges

M temp. range

±0.02 nA

TA= +25°C

VCM= 1.5V

C/E temp. ranges

M temp. range

MAX921, MAX923

C/E temp. ranges

M temp. range

TA= +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, TA = +25°C, unless otherwise noted).

0.0
020

OUTPUT VOLTAGE LOW

vs. LOAD CURRENT

0.5

2.5

MAX921/4-TOC1

LOAD CURRENT (mA)

V

OL

(V)

12

1.5

1.0

48 16

2.0

V+ = 5V

V+ = 3V

1.5
010 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 (μA)

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, TA= 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 VV- V+ – 1.3

MAX922/
MAX923

TA= +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

µsResponse Time

5

C temp. range

VOutput High Voltage

E temp. range

MAX92_

M temp. range

V+ – 0.4

TA= +25°C

V- + 0.4

V

15 25

µA

C/E temp. ranges 6

Source Current

M temp. range 4

TA= +25°C

GND + 0.4

Output Low Voltage

815

MAX921/
MAX924

µA

C/E temp. ranges 4

Sink Current

1.170 1.182 1.194

V

M temp. range

1.158 1.206Reference 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 8040 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 (μA)

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 (μA)

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 (μA)

60

3.0

2.5

-20 20 100

3.5

V+ = 5V, V- = 0V

V+ = 3V, V- = 0V

80

-80
010 30 50

HYSTERESIS CONTROL

-40

40

MAX921/924 TOC10

V

REF

-V

HYST

(mV)

IN+ – IN- (mV)

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 (μA)

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 (μA)

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

10μF

18

2

0 20 60 100

RESPONSE TIME vs.
LOAD CAPACITANCE

6

14

MAX921/924 TOC12

LOAD CAPACITANCE (nF)

RESPONSE TIME (μs)

40 80

10

16

4

12

8

V

OLH

V- = 0V

V

OHL

Typical Operating Characteristics (continued)

(V+ = 5V, V- = GND, TA = +25°C, unless otherwise noted).

MAX921–MAX924

Ultra Low-Power,
Single/Dual-Supply Comparators

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(V+ = 5V, V- = GND, TA = +25°C, unless otherwise noted).

-2 2 10 18

RESPONSE TIME FOR VARIOUS

INPUT OVERDRIVES

0

4

MAX921/924-TOC13

RESPONSE TIME (μs)

OUTPUT VOLTAGE (V)

614

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 (μs)

OUTPUT VOLTAGE (V)

614

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

010

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