MAXIM MAX9021, MAX9022, MAX9024 User Manual

General Description

The MAX9021/MAX9022/MAX9024 single/dual/quad
comparators are optimized for low-power consumption
while still providing a fast output response. They are
designed for single-supply applications from 2.5V to

5.5V, but can also operate from dual supplies. These
comparators have a 3µs propagation delay and con­sume 2.8µA of supply current per comparator over the

-40°C to +125°C operating temperature range. The
combination of low-power, single-supply operation
down to 2.5V, and ultra-small footprint makes these
devices ideal for portable applications.

The MAX9021/MAX9022/MAX9024 have 4mV of built-in
hysteresis to provide noise immunity and prevent oscil­lations even with a slow-moving input signal. The input
common-mode range extends from the negative supply
to within 1.1V of the positive supply. The design of the
comparator-output stage substantially reduces switch­ing current during output transitions, eliminating power­supply glitches.

The MAX9021 single comparator is available in tiny 5­pin SC70 and SOT23 packages. The MAX9022 dual
comparator is available in 8-pin SOT23, µMAX®, and
SO packages, and the MAX9024 quad comparator is
available in 14-pin TSSOP and SO packages.

Features

♦ Low-Cost Solution Available in Space-Saving

SC70 Packages (Half the Size of SOT23)

♦ Low 2.8µA Supply Current

♦ 3µs Propagation Delay

♦ Internal 4mV Comparator Hysteresis

♦ Comparator Output Swings Rail-to-Rail

♦ 2.5 to 5.5V Single-Supply Voltage Range

♦ No Phase Reversal for Overdriven Inputs

♦ Space-Saving Packages

5-Pin SC70 (MAX9021)
8-Pin SOT23 (MAX9022)
8-Pin µMAX (MAX9022)
14-Pin TSSOP (MAX9024)

MAX9021/MAX9022/MAX9024

Micropower, Ultra-Small, Single/Dual/Quad,

Single-Supply Comparators

________________________________________________________________ Maxim Integrated Products 1

TOP VIEW

V

SS

OUTIN-

15V

DD

IN+

MAX9021

SC70/SOT23

2

34

INB-

INB+V

SS

1

2

87V

DD

OUTBINA-

INA+

OUTA

S0T23/µMAX/SO

3

4

6

5

MAX9022

14

13

12

11

10

9

8

1

2

3

4

5

6

7

OUTD

IND-

IND+

V

SS

V

DD

INA+

INA-

OUTA

MAX9024

INC+

INC-

OUTCOUTB

INB-

INB+

TSSOP/SO

Pin Configurations

19-1842; Rev 2; 1/07

Ordering Information

Battery-Powered
Portable Systems

Mobile Communications
Sensor-Signal Detection
Photodiode Preamps

Digital Line Receivers
Keyless Entry Systems
Threshold Detectors/

Discriminators

Typical Application Circuit appears at end of data sheet.

PA RT

TEMP RANGE

PIN-

PKG
CODE

5 SC70-5

X5-1

U5-1

K8-5

MAX9022AUA

8 µMAX

U8-1

MAX9022ASA

8 SO

S8-2

MAX9024AUD

U14-1

MAX9024ASD

14 SO

S14-2

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

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Applications

PACKAGE

MAX9021AXK-T -40°C to +125°C

MAX9021AUK-T -40°C to +125°C

MAX9022AKA-T -40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

5 SOT23-5

8 SOT23-8

14 TSSOP

MAX9021/MAX9022/MAX9024

Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

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.

Supply Voltage (VDDto VSS) ....................................-0.3V to +6V

Voltage Inputs (IN+, IN- to V

SS

). ................-0.3V to (VDD+ 0.3V)

Differential Input Voltage (IN+ to IN-)....................................6.6V

Current into Input Pins ......................................................±20mA

Output Short-Circuit Duration ..................2s to Either V

DD

or V

SS

Current into Any Pin ............................................................20mA

Continuous Power Dissipation (TA= +70°C)

5-Pin SC70 (derate 3.1mW/°C above +70°C)...............247mW

5-Pin SOT23 (derate 7.1mW/°C above +70°C).............571mW

8-Pin SOT23 (derate 9.1mW/°C above +70°C).............727mW

8-Pin µMAX (derate 4.5mW/°C above +70°C) ..............362mW

8-Pin SO (derate 5.88mW/°C above +70°C).................471mW

14-Pin TSSOP (derate 9.1mW/°C above +70°C) ..........727mW

14-Pin SO (derate 8.3mW/°C above +70.......................667mW

Operating Temperature Range

Automotive Application...................................-40°C to +125°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Operating Voltage Range V

DD

Guaranteed by PSRR test

2.5

5.5 V

S up p l y C ur r ent P er C om p ar ator I

DD

2.8 5 µA

Input Offset Voltage V

OS

(Note 2) ±1 ±8mV

Input Offset Voltage
Temperature Coefficient

±1

µV/°C

Hysteresis (Note 3) 4 mV

Input Bias Current I

BIAS

380nA

Input Offset Current I

OS

±2 ±60 nA

Common-Mode Voltage Range V

CM

Guaranteed by CMRR test

V

C om m on- M od e Rej ecti on Rati o

V

S S

≤ V

C M

≤ ( V

D D

- 1.1V ) , V

D D

= 5.5V 70 100 d B

Power-Supply Rejection Ratio

V

DD

= 2.5V to 5.5V 60 80 dB

I

SOURCE

= 10µA 2

VOH = VDD - V

OUT,

(V

IN+

- V

IN-

) ≥ 20mV

I

SOURCE

= 4mA

400

I

SINK

= 10µA 2

Output-Voltage Swing

V

OL

= V

OUT

- V

SS,

(V

IN-

- V

IN+

) ≥ 20mV

I

SINK

= 4mA

400

mV

Output Short-Circuit Current I

SC

50 m A

VOD = 10mV 8

Propagation Delay

p

p

RL = 10kΩ,
C

L

= 15pF (Note 4)

V

OD

= 100mV 3

µs

Rise and Fall Time tR, t

F

RL = 10kΩ, CL = 15pF (Note 5) 20 ns

Power-On Time RL = 10kΩ, CL = 15pF

ns

Maximum Capacitive Load C

L

No sustained oscillations

pF

Note 1: All devices are production tested at 25°C. All temperature limits are guaranteed by design.
Note 2: Comparator Input Offset is defined as the center of the hysteresis zone.
Note 3: Hysteresis is defined as the difference of the trip points required to change comparator output states.
Note 4: V

OD

is the overdrive voltage beyond the offset and hysteresis-determined trip points.

Note 5: Rise and fall times are measured between 10% and 90% at OUT.

ELECTRICAL CHARACTERISTICS

(VDD= 5V, VSS= 0, VCM= 0, TA= -40°C to +125°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)

TCV

OS

V

SS

CMRR

PSRR

V

, V

OL

t

, t

d+

OH

d

-

160

180

150

150

VDD - 1.1

MAX9021/MAX9022/MAX9024

Micropower, Ultra-Small, Single/Dual/Quad,

Single-Supply Comparators

_______________________________________________________________________________________ 3

Typical Operating Characteristics

(VDD= 5V, VSS= 0, VCM= 0, RL= 10kΩ, CL= 15pF, VOD= 100mV, TA= +25°C, unless otherwise noted.)

3.0

2.9

2.8

2.7

2.6
24356

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX9021/2/4 toc01

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (µA)

2.5

2.6

2.8

2.7

2.9

3.0

-50 0-25 25 50 75 100 125

SUPPLY CURRENT vs. TEMPERATURE

MAX9021/2/4 toc02

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

1000

1

0.01 1 1000

SUPPLY CURRENT

vs. OUTPUT TRANSITION FREQUENCY

10

100

MAX9021/2/4 toc03

OUTPUT TRANSITION FREQUENCY (kHz)

SUPPLY CURRENT (µA)

0.1

10

100

0

0.4

0.2

0.8

0.6

1.2

1.0

1.4

-50 0 25-25 50 75 100 125

INPUT OFFSET VOLTAGE

vs. TEMPERATURE

MAX9021/2/4 toc04

TEMPERATURE (°C)

INPUT OFFSET VOLTAGE (mV)

0

100

200

300

400

500

0426810

OUTPUT HIGH VOLTAGE

vs. SOURCE CURRENT

MAX9021/2/4 toc05

SOURCE CURRENT (mA)

(V

DD

- V

OUT

) (mV)

0

100

200

300

400

500

0426810

OUTPUT LOW VOLTAGE

vs. SINK CURRENT

MAX9021/2/4 toc06

SINK CURRENT (mA)

OUTPUT LOW VOLTAGE (mV)

40

45

55

50

60

65

-50 0-25 25 50 75 100 125

OUTPUT SHORT-CIRCUIT CURRENT

vs. TEMPERATURE

MAX9021/2/4 toc07

TEMPERATURE (°C)

OUTPUT SHORT-CIRCUIT CURRENT (mA)

SOURCE CURRENT

SINK CURRENT

0

1

2

3

4

5

0

PROPAGATION DELAY vs. CAPACITIVE LOAD

(V

DD

= 2.7V)

MAX9021/2/4 toc08

CAPACITIVE LOAD (pF)

PROPAGATION DELAY (µs)

tPD-

tPD+

500 1000

1500

2000

0

1

2

3

4

5

PROPAGATION DELAY vs. CAPACITIVE LOAD

(V

DD

= 5V)

MAX9021/2/4 toc09

CAPACITIVE LOAD (pF)

PROPAGATION DELAY (µs)

tPD-

0 500 1000

1500

2000

tPD+

MAX9021/MAX9022/MAX9024

Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators

4 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VDD= 5V, VSS= 0, VCM= 0, RL= 10kΩ, CL= 15pF, VOD= 100mV, TA= +25°C, unless otherwise noted.)

0

1

3

2

4

5

-50 0-25 25 50 75 100 125

PROPAGATION DELAY

vs. TEMPERATURE

MAX9021/2/4 toc10

TEMPERATURE (°C)

PROPAGATION DELAY (µs)

tPD-

tPD+

0

2

1

5

4

3

8

7

6

9

0406020 80 100 120 140

PROPAGATION DELAY

vs. INPUT OVERDRIVE VOLTAGE

MAX9021/2/4 toc11

INPUT OVERDRIVE VOLTAGE (mV)

PROPAGATION DELAY (µs)

tPD+

tPD-

PROPAGATION DELAY (t

PD+

)

MAX9021/2/4 toc12

1µs/div

IN+

100mV/div

V

OUT

2.5V/div

PROPAGATION DELAY (t

PD-

)

MAX9021/2/4 toc13

1µs/div

IN+

100mV/div

V

OUT

2.5V/div

OUTPUT SWITCHING CURRENT, RISING

MAX9021/2/4 toc14

20µs/div

IN+ - IN-

200mV/div

V

OUT

5V/div

SWITCHING

CURRENT

400µA/div

OUTPUT SWITCHING CURRENT, FALLING

MAX9021/2/4 toc15

20µs/div

IN+ - IN-

200mV/div

V

OUT

5V/div

SWITCHING

CURRENT

400µA/div

10kHz RESPONSE

(V

OD

= 10mV)

MAX9021/2/4 toc16

10µs/div

IN+ - IN-

10mV/div

OUT

2.5V/div

10kHz RESPONSE

(V

OD

= 100mV)

MAX9021/2/4 toc17

10µs/div

IN+ - IN-

100mV/div

OUT

2.5V/div

POWER-UP TIME

MAX9021/2/4 toc18

2µs/div

V

DD

2.5V/div

V

OUT

2.5V/div

MAX9021/MAX9022/MAX9024

Micropower, Ultra-Small, Single/Dual/Quad,

Single-Supply Comparators

_______________________________________________________________________________________ 5

Detailed Description

The MAX9021/MAX9022/MAX9024 are single/dual/
quad, low-cost, low-power comparators that consume
only 2.8µA and provide a propagation delay, tPD, typi­cally 3µs. They have an operating-supply voltage from

2.5V to 5.5V when operating from a single supply and
from ±1.25V to ±2.75V when operating from dual power
supplies. Their common-mode input voltage range
extends from the negative supply to within 1.1V of the
positive supply. Internal hysteresis ensures clean out­put switching, even with slow-moving input signals.

Applications Information

Adding Hysteresis

Hysteresis extends the comparator’s noise margin by
increasing the upper threshold and decreasing the
lower threshold. A voltage-divider from the compara-

tor’s output sets the trip voltage. Therefore, the trip volt­age is related to the output voltage.

These comparators have 4mV internal hysteresis.
Additional hysteresis can be generated with two resis­tors, using positive feedback (Figure 1). Use the follow­ing procedure to calculate resistor values:

1) Find the trip points of the comparator using these for­mulas:

V

TH

= V

REF

+ ((VDD- V

REF

)R2) / (R1 + R2)

V

TL

= V

REF

(1 - (R2 / (R1 + R2))

where VTHis the threshold voltage at which the com­parator switches its output from high to low as V

IN

rises above the trip point. VTLis the threshold volt­age at which the comparator switches its output from
low to high as V

IN

drops below the trip point.

Pin Description

PIN

M A X9 0 2 1

M A X9 0 2 4

NAME FUNCTION

1— — IN+ Comparator Noninverting Input

2411VSSNegative Supply Voltage

3— — IN- Comparator Inverting Input

4— — OUT Comparator Output

58 4 VDDPositive Supply Voltage. Bypass with a 0.1µF capacitor to GND.

—1 1OUTA Comparator A Output

—2 2 INA- Comparator A Inverting Input

—3 3 INA+ Comparator A Noninverting Input

—5 5 INB+ Comparator B Noninverting Input

—6 6 INB- Comparator B Inverting Input

—7 7OUTB Comparator B Output

—— 8 OUTC Comparator C Output

—— 9 INC- Comparator C Inverting Input

—— 10 INC+ Comparator C Noninverting Input

—— 12 IND+ Comparator D Noninverting Input

—— 13 IND- Comparator D Inverting Input

—— 14 OUTD Comparator D Output

M A X9 0 2 2

MAX9021/MAX9022/MAX9024

Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators

6 _______________________________________________________________________________________

2) The hysteresis band will be:

V

HYS

= VTH- VTL= VDD(R2 / (R1 + R2))

3) In this example, let VDD= 5V and V

REF

= 2.5V.

V

TH

= 2.5V + 2.5V(R2 / (R1 + R2))

and

VTL= 2.5V[(1 - (R2 / (R1 + R2))]

4) Select R2. In this example, we will choose 1kΩ.

5) Select V

HYS

. In this example, we will choose 50mV.

6) Solve for R1.

V

HYS

= VDD(R2 / (R1 + R2))

0.050V = 5(1000Ω/(R1 + 1000Ω)) V

where R1 ≈ 100kΩ, VTH= 2.525V, and VTL= 2.475V.

The above-described design procedure assumes rail­to-rail output swing. If the output is significantly loaded,
the results should be corrected.

Board Layout and Bypassing

Use 100nF bypass as a starting point. Minimize signal
trace lengths to reduce stray capacitance. Minimize the
capacitive coupling between IN- and OUT. For slow­moving input signals (rise time > 1ms), use a 1nF
capacitor between IN+ and IN-.

Biasing for Data Recovery

Digital data is often embedded into a bandwidth and
amplitude-limited analog path. Recovering the data can
be difficult. Figure 2 compares the input signal to a
time-averaged version of itself. This self-biases the
threshold to the average input voltage for optimal noise
margin. Even severe phase distortion is eliminated from
the digital output signal. Be sure to choose R1 and C1
so that:

f

CAR

>> 1 / (2πR1C1)

where f

CAR

is the fundamental carrier frequency of the

digital data stream.

MAX9021

OUT

IN+

IN-

R2

R1

V

IN

V

REF

V

DD

V

SS

V

DD

Figure 1. Additional Hysteresis

MAX9021

OUT

IN+

IN-

10kΩ

0.1µF

V

DD

V

IN

V

SS

V

DD

Figure 2. Time Averaging of the Input Signal for Data Recovery

MAX9021/MAX9022/MAX9024

Micropower, Ultra-Small, Single/Dual/Quad,

Single-Supply Comparators

_______________________________________________________________________________________ 7

MAX9021

OUT

IN+

IN-

V

IN

V

DD

V

DD

V

REF

R1

R2

RL

0.1µF

Typical Application Circuit Chip Information

MAX9021 TRANSISTOR COUNT: 106
MAX9022 TRANSISTOR COUNT: 212
MAX9024 TRANSISTOR COUNT: 424

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages

.)

SC70, 5L.EPS

PACKAGE OUTLINE, 5L SC70

21-0076

1

D

1

MAX9021/MAX9022/MAX9024

Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.

Package Information (continued)

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to

www.maxim-ic.com/packages.)

Revision History

Pages changed at Rev 2: 1, 2, 6, 7, 8

SOT-23 5L .EPS

SOT23, 8L .EPS