19-1842; Rev 2; 1/07
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
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)
Applications
Battery-Powered
Portable Systems
Mobile Communications
Sensor-Signal Detection
Photodiode Preamps
Digital Line Receivers
Keyless Entry Systems
Threshold Detectors/
Discriminators
Ordering Information
PINPACKAGE
PKG
CODE
MAX9021AXK-T -40°C to +125°C
5 SC70-5
X5-1
MAX9021AUK-T -40°C to +125°C
5 SOT23-5
U5-1
MAX9022AKA-T -40°C to +125°C
8 SOT23-8
K8-5
MAX9022AUA
-40°C to +125°C
8 µMAX
U8-1
MAX9022ASA
-40°C to +125°C
8 SO
S8-2
MAX9024AUD
-40°C to +125°C
14 TSSOP
U14-1
-40°C to +125°C
14 SO
S14-2
PART
TEMP RANGE
MAX9024ASD
Typical Application Circuit appears at end of data sheet.
Pin Configurations
TOP VIEW
IN+ 1
VSS 2
5
VDD
OUTA 1
INA- 2
MAX9021
8
VDD
7
OUTB
MAX9022
3
6
INB-
VSS 4
5
INB+
INA+
OUTA 1
INA-
2
13 IND-
INA+
3
12 IND+
VDD 4
IN- 3
4
SC70/SOT23
OUT
S0T23/µMAX/SO
14 OUTD
MAX9024
11 VSS
INB+ 5
10 INC+
INB- 6
9
INC-
OUTB 7
8
OUTC
TSSOP/SO
µMAX is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX9021/MAX9022/MAX9024
General Description
MAX9021/MAX9022/MAX9024
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VDD to VSS) ....................................-0.3V to +6V
Voltage Inputs (IN+, IN- to VSS). ................-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 VDD or VSS
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
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
(VDD = 5V, VSS = 0, VCM = 0, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
Operating Voltage Range
SYMBOL
VDD
Supply Current Per Comparator
IDD
Input Offset Voltage
VOS
Input Offset Voltage
Temperature Coefficient
MIN
(Note 2)
(Note 3)
IOS
Common-Mode Voltage Range
VCM
MAX
UNITS
5.5
V
2.8
5
µA
±1
±8
mV
±1
µV/°C
4
IBIAS
Input Offset Current
TYP
2.5
TCVOS
Hysteresis
Input Bias Current
CONDITIONS
Guaranteed by PSRR test
3
±2
Guaranteed by CMRR test
VSS
mV
80
nA
±60
nA
VDD - 1.1
V
Common-Mode Rejection Ratio
CMRR
VSS ≤ VCM ≤ (VDD - 1.1V), VDD = 5.5V
70
100
dB
Power-Supply Rejection Ratio
PSRR
VDD = 2.5V to 5.5V
60
80
dB
Output-Voltage Swing
Output Short-Circuit Current
VOL, VOH
tpd+, tpd-
Rise and Fall Time
tR , tF
Power-On Time
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
2
VOL = VOUT - VSS,
(VIN- - VIN+) ≥ 20mV
ISOURCE = 10µA
2
ISOURCE = 4mA
160
ISINK = 10µA
2
ISINK = 4mA
180
ISC
Propagation Delay
Maximum Capacitive Load
VOH = VDD - VOUT,
(VIN+ - VIN-) ≥ 20mV
CL
50
RL = 10kΩ,
CL = 15pF (Note 4)
VOD = 10mV
8
VOD = 100mV
3
400
mV
400
mA
µs
RL = 10kΩ, CL = 15pF (Note 5)
20
ns
RL = 10kΩ, CL = 15pF
150
ns
No sustained oscillations
150
pF
All devices are production tested at 25°C. All temperature limits are guaranteed by design.
Comparator Input Offset is defined as the center of the hysteresis zone.
Hysteresis is defined as the difference of the trip points required to change comparator output states.
VOD is the overdrive voltage beyond the offset and hysteresis-determined trip points.
Rise and fall times are measured between 10% and 90% at OUT.
_______________________________________________________________________________________
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
2.8
2.7
MAX9021/2/4 toc03
2.9
1000
SUPPLY CURRENT (µA)
2.8
MAX9021/2/4 toc02
2.9
3.0
SUPPLY CURRENT (µA)
MAX9021/2/4 toc01
3.0
SUPPLY CURRENT (µA)
SUPPLY CURRENT
vs. OUTPUT TRANSITION FREQUENCY
SUPPLY CURRENT vs. TEMPERATURE
100
10
2.7
2.6
1
2.5
3
4
5
6
-50
-25
0
1.0
0.8
0.6
100
0.01
125
100
10
1
0.1
OUTPUT TRANSITION FREQUENCY (kHz)
OUTPUT HIGH VOLTAGE
vs. SOURCE CURRENT
OUTPUT LOW VOLTAGE
vs. SINK CURRENT
MAX9021/2/4 toc05
400
(VDD - VOUT) (mV)
INPUT OFFSET VOLTAGE (mV)
1.2
75
500
MAX9021/2/4 toc04
1.4
50
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
25
300
200
0.4
500
OUTPUT LOW VOLTAGE (mV)
2
100
1000
MAX9021/2/4 toc06
2.6
400
300
200
100
0.2
0
0
-25
0
25
50
75
100
2
4
6
8
10
2
4
6
8
10
PROPAGATION DELAY vs. CAPACITIVE LOAD
(VDD = 2.7V)
PROPAGATION DELAY vs. CAPACITIVE LOAD
(VDD = 5V)
5
5
MAX9021/2/4 toc07
55
SOURCE CURRENT
50
SINK CURRENT
4
3
tPD-
2
tPD+
-25
0
25
50
75
TEMPERATURE (°C)
100
125
tPD3
2
tPD+
0
0
40
4
1
1
45
MAX9021/2/4 toc09
OUTPUT SHORT-CIRCUIT CURRENT
vs. TEMPERATURE
PROPAGATION DELAY (µs)
SINK CURRENT (mA)
MAX9021/2/4 toc08
SOURCE CURRENT (mA)
60
-50
0
TEMPERATURE (°C)
65
OUTPUT SHORT-CIRCUIT CURRENT (mA)
0
0
125
PROPAGATION DELAY (µs)
-50
0
500
1000
1500
CAPACITIVE LOAD (pF)
2000
0
500
1000
1500
2000
CAPACITIVE LOAD (pF)
_______________________________________________________________________________________
3
MAX9021/MAX9022/MAX9024
Typical Operating Characteristics
(VDD = 5V, VSS = 0, VCM = 0, RL = 10kΩ, CL = 15pF, VOD = 100mV, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VDD = 5V, VSS = 0, VCM = 0, RL = 10kΩ, CL = 15pF, VOD = 100mV, TA = +25°C, unless otherwise noted.)
PROPAGATION DELAY
vs. INPUT OVERDRIVE VOLTAGE
3
2
tPD+
MAX9021/2/4 toc11
tPD-
8
7
IN+
100mV/div
6
5
4
tPD-
VOUT
2.5V/div
3
2
1
PROPAGATION DELAY (tPD+)
9
PROPAGATION DELAY (µs)
4
MAX9021/2/4 toc10
5
MAX9021/2/4 toc12
PROPAGATION DELAY
vs. TEMPERATURE
PROPAGATION DELAY (µs)
tPD+
1
0
-25
0
25
50
75
100
0
125
20
40
60
80
100
120
140
INPUT OVERDRIVE VOLTAGE (mV)
PROPAGATION DELAY (tPD-)
OUTPUT SWITCHING CURRENT, RISING
IN+
100mV/div
IN+ - IN200mV/div
1µs/div
OUTPUT SWITCHING CURRENT, FALLING
MAX9021/2/4 toc14
TEMPERATURE (°C)
MAX9021/2/4 toc13
-50
MAX9021/2/4 toc15
0
IN+ - IN200mV/div
VOUT
5V/div
VOUT
5V/div
SWITCHING
CURRENT
400µA/div
SWITCHING
CURRENT
400µA/div
VOUT
2.5V/div
20µs/div
10kHz RESPONSE
(VOD = 10mV)
10kHz RESPONSE
(VOD = 100mV)
POWER-UP TIME
IN+ - IN10mV/div
10µs/div
VDD
2.5V/div
VOUT
2.5V/div
OUT
2.5V/div
OUT
2.5V/div
4
IN+ - IN100mV/div
MAX9021/2/4 toc18
20µs/div
MAX9021/2/4 toc17
1µs/div
MAX9021/2/4 toc16
MAX9021/MAX9022/MAX9024
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
10µs/div
_______________________________________________________________________________________
2µs/div
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
PIN
NAME
FUNCTION
MAX9021
MAX9022
MAX9024
1
—
—
IN+
Comparator Noninverting Input
2
4
11
VSS
Negative Supply Voltage
3
—
—
IN-
Comparator Inverting Input
4
—
—
OUT
Comparator Output
5
8
4
VDD
Positive Supply Voltage. Bypass with a 0.1µF capacitor to GND.
—
1
1
OUTA
—
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
7
OUTB
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 A Output
Comparator D Output
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:
VTH = VREF + ((VDD - VREF)R2) / (R1 + R2)
VTL = VREF(1 - (R2 / (R1 + R2))
where VTH is the threshold voltage at which the comparator switches its output from high to low as VIN
rises above the trip point. VTL is the threshold voltage at which the comparator switches its output from
low to high as VIN drops below the trip point.
_______________________________________________________________________________________
5
MAX9021/MAX9022/MAX9024
Pin Description
MAX9021/MAX9022/MAX9024
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
R1
R2
VREF
VDD
VDD
VDD
VDD
VIN
IN+
OUT
VIN
OUT
10kΩ
IN-
MAX9021
VSS
Figure 1. Additional Hysteresis
2) The hysteresis band will be:
VHYS = VTH - VTL = VDD(R2 / (R1 + R2))
3) In this example, let VDD = 5V and VREF = 2.5V.
VTH = 2.5V + 2.5V(R2 / (R1 + R2))
and
0.1µF
INVSS
MAX9021
Figure 2. Time Averaging of the Input Signal for Data Recovery
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
VTL = 2.5V[(1 - (R2 / (R1 + R2))]
4) Select R2. In this example, we will choose 1kΩ.
5) Select VHYS. In this example, we will choose 50mV.
6) Solve for R1.
VHYS = 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.
6
IN+
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:
fCAR >> 1 / (2πR1C1)
where fCAR is the fundamental carrier frequency of the
digital data stream.
_______________________________________________________________________________________
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
MAX9021 TRANSISTOR COUNT: 106
MAX9022 TRANSISTOR COUNT: 212
MAX9024 TRANSISTOR COUNT: 424
VDD
VIN
0.1µF
R1
Chip Information
VDD
IN+
VREF
OUT
INRL
R2
MAX9021
Package Information
SC70, 5L.EPS
(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.)
PACKAGE OUTLINE, 5L SC70
21-0076
D
1
1
_______________________________________________________________________________________
7
MAX9021/MAX9022/MAX9024
Typical Application Circuit
Package Information (continued)
SOT-23 5L .EPS
(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.)
SOT23, 8L .EPS
MAX9021/MAX9022/MAX9024
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
Revision History
Pages changed at Rev 2: 1, 2, 6, 7, 8
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.
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