19-1842; Rev 1; 7/01
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
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 con-
sume 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 oscil-
lations 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 switch-
ing current during output transitions, eliminating power-
supply glitches.
The MAX9021 single comparator is available in tiny 5-
pin SC70 and SOT23 packages. The MAX9022 dual
comparator is available in 8-pin SOT23, µMAX, and SO
packages, and the MAX9024 quad comparator is avail-
able in 14-pin TSSOP and SO packages.
Features
o
Low-Cost Solution Available in Space-Saving
SC70 Packages (Half the Size of SOT23)
o
Low 2.8µA Supply Current
o
3µs Propagation Delay
o
Internal 4mV Comparator Hysteresis
o
Comparator Output Swings Rail-to-Rail
®
o
2.5 to 5.5V Single-Supply Voltage Range
o
No Phase Reversal for Overdriven Inputs
o
Space-Saving Packages
5-Pin SC70 (MAX9021)
8-Pin SOT23 (MAX9022)
8-Pin µMAX (MAX9022)
14-Pin TSSOP (MAX9024)
MAX9021/MAX9022/MAX9024
Ordering Information
PART
MAX9021AXK-T
MAX9021AUK-T
MAX9022AKA-T
MAX9022AUA
MAX9022ASA
MAX9024AUD
MAX9024ASD
TEMP RANGE
-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
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
5 SC70-5
5 SOT23-5
8 SOT23-8
8 µMAX
8 SO
14 TSSOP
14 SO
Applications
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.
Pin Configurations
TOP VIEW
IN+ 1
5
V
DD
OUTA 1
INA- 2
8
7
V
DD
OUTB
INB-
V
DD
4
IN- 3
4
OUT
V
SS
4
5
INB+
INB+ 5
INB- 6
OUTA 1
INA-
INA+
6
2
3
14 OUTD
13 IND-
12 IND+
V
SS
2
MAX9021
MAX9022
INA+
3
MAX9024
11 V
SS
10 INC+
9
8
INC-
OUTC
SC70/SOT23
S0T23/µMAX/SO
OUTB 7
TSSOP/SO
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
________________________________________________________________
Maxim Integrated Products
1
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.
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
MAX9021/MAX9022/MAX9024
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
DD
to V
SS
) ....................................-0.3V to +6V
Voltage Inputs (IN+, IN- to V
SS
). ................-0.3V to (V
DD
+ 0.3V)
Differential Input Voltage (IN+ to IN-)....................................6.6V
Output Short-Circuit Duration ..................2s to Either V
DD
or V
SS
Current into Any Pin ............................................................20mA
Continuous Power Dissipation (T
A
= +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
(V
DD
= 5V, V
SS
= 0, V
CM
= 0, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Operating Voltage Range
Supply Current Per Comparator
Input Offset Voltage
Input Offset Voltage
Temperature Coefficient
Hysteresis
Input Bias Current
Input Offset Current
Common-Mode Voltage Range
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
I
BIAS
I
OS
V
CM
CMRR
PSRR
Guaranteed by CMRR test
V
SS
≤
V
CM
≤
(V
DD
- 1.1V), V
DD
= 5.5V
V
DD
= 2.5V to 5.5V
V
OH
= V
DD
- V
OUT,
(V
IN+
- V
IN-
)
≥
20mV
V
OL
= V
OUT
- V
SS,
(V
IN-
- V
IN+
)
≥
20mV
R
L
= 10kΩ,
C
L
= 15pF (Note 4)
R
L
= 10kΩ, C
L
= 15pF
C
L
No sustained oscillations
I
SOURCE
= 10µA
I
SOURCE
= 4mA
I
SINK
= 10µA
I
SINK
= 4mA
V
OD
= 10mV
V
OD
= 100mV
V
SS
70
60
100
80
2
160
2
180
50
8
3
20
150
150
400
mA
µs
ns
ns
pF
400
mV
SYMBOL
V
DD
I
DD
V
OS
TCV
OS
(Note 3)
(Note 2)
CONDITIONS
Guaranteed by PSRR test
MIN
2.5
2.8
±1
±1
4
3
±2
80
±60
V
DD
- 1.1
TYP
MAX
5.5
5
±8
UNITS
V
µA
mV
µV/°C
mV
nA
nA
V
dB
dB
Output-Voltage Swing
V
OL
, V
OH
Output Short-Circuit Current
Propagation Delay
Rise and Fall Time
Power-On Time
Maximum Capacitive Load
I
SC
t
pd+
, t
pd
-
t
R
, t
F
R
L
= 10kΩ, C
L
= 15pF (Note 5)
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
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.
V
OD
is the overdrive voltage beyond the offset and hysteresis-determined trip points.
Rise and fall times are measured between 10% and 90% at OUT.
2
_______________________________________________________________________________________
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
MAX9021/MAX9022/MAX9024
Typical Operating Characteristics
(V
DD
= 5V, V
SS
= 0, V
CM
= 0, R
L
= 10kΩ, C
L
= 15pF, V
OD
= 100mV, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX9021/2/4 toc01
SUPPLY CURRENT vs. TEMPERATURE
MAX9021/2/4 toc02
SUPPLY CURRENT
vs. OUTPUT TRANSITION FREQUENCY
MAX9021/2/4 toc03
3.0
3.0
1000
SUPPLY CURRENT (µA)
SUPPLY CURRENT (µA)
SUPPLY CURRENT (µA)
2.9
2.9
100
2.8
2.8
2.7
10
2.7
2.6
1
-50
-25
0
25
50
75
100
125
0.01
0.1
1
10
100
1000
TEMPERATURE (°C)
OUTPUT TRANSITION FREQUENCY (kHz)
2.6
2
3
4
SUPPLY VOLTAGE (V)
5
6
2.5
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
MAX9021/2/4 toc04
OUTPUT HIGH VOLTAGE
vs. SOURCE CURRENT
MAX9021/2/4 toc05
OUTPUT LOW VOLTAGE
vs. SINK CURRENT
MAX9021/2/4 toc06
1.4
1.2
INPUT OFFSET VOLTAGE (mV)
1.0
0.8
0.6
0.4
500
500
300
OUTPUT LOW VOLTAGE (mV)
400
(V
DD
- V
OUT
) (mV)
400
300
200
200
100
0.2
0
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
0
0
2
4
6
8
10
SOURCE CURRENT (mA)
100
0
0
2
4
6
8
10
SINK CURRENT (mA)
OUTPUT SHORT-CIRCUIT CURRENT
vs. TEMPERATURE
OUTPUT SHORT-CIRCUIT CURRENT (mA)
MAX9021/2/4 toc07
PROPAGATION DELAY vs. CAPACITIVE LOAD
(V
DD
= 2.7V)
MAX9021/2/4 toc08
PROPAGATION DELAY vs. CAPACITIVE LOAD
(V
DD
= 5V)
MAX9021/2/4 toc09
65
5
5
PROPAGATION DELAY (µs)
PROPAGATION DELAY (µs)
60
4
4
t
PD
-
3
55
SOURCE CURRENT
50
SINK CURRENT
45
3
t
PD
-
2
t
PD
+
2
t
PD
+
1
1
40
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
0
0
500
1000
1500
2000
CAPACITIVE LOAD (pF)
0
0
500
1000
1500
2000
CAPACITIVE LOAD (pF)
_______________________________________________________________________________________
3
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
MAX9021/MAX9022/MAX9024
Typical Operating Characteristics (continued)
(V
DD
= 5V, V
SS
= 0, V
CM
= 0, R
L
= 10kΩ, C
L
= 15pF, V
OD
= 100mV, T
A
= +25°C, unless otherwise noted.)
PROPAGATION DELAY
vs. TEMPERATURE
MAX9021/2/4 toc10
PROPAGATION DELAY
vs. INPUT OVERDRIVE VOLTAGE
MAX9021/2/4 toc11
PROPAGATION DELAY (t
PD+
)
MAX9021/2/4 toc12
5
9
8
PROPAGATION DELAY (µs)
7
6
5
4
3
2
1
t
PD
+
t
PD
-
PROPAGATION DELAY (µs)
4
t
PD
-
IN+
100mV/div
3
2
t
PD
+
V
OUT
2.5V/div
1
0
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
0
0
20
40
60
80
100
120
140
1µs/div
INPUT OVERDRIVE VOLTAGE (mV)
PROPAGATION DELAY (t
PD-
)
MAX9021/2/4 toc13
OUTPUT SWITCHING CURRENT, RISING
MAX9021/2/4 toc14
OUTPUT SWITCHING CURRENT, FALLING
MAX9021/2/4 toc15
IN+
100mV/div
IN+ - IN -
200mV/div
V
OUT
5V/div
IN+ - IN-
200mV/div
V
OUT
5V/div
V
OUT
2.5V/div
SWITCHING
CURRENT
400µA/div
SWITCHING
CURRENT
400µA/div
1µs/div
20µs/div
20µs/div
10kHz RESPONSE
(V
OD
= 10mV)
MAX9021/2/4 toc16
10kHz RESPONSE
(V
OD
= 100mV)
MAX9021/2/4 toc17
POWER-UP TIME
MAX9021/2/4 toc18
IN+ - IN -
10mV/div
IN+ - IN-
100mV/div
V
DD
2.5V/div
OUT
2.5V/div
OUT
2.5V/div
V
OUT
2.5V/div
10µs/div
10µs/div
2µs/div
4
_______________________________________________________________________________________
Micropower, Ultra-Small, Single/Dual/Quad,
Single-Supply Comparators
Pin Description
PIN
NAME
MAX9021
1
2
3
4
5
—
—
—
—
—
—
—
—
—
—
—
—
MAX9022
—
4
—
—
8
1
2
3
5
6
7
—
—
—
—
—
—
MAX9024
—
11
—
—
4
1
2
3
5
6
7
8
9
10
12
13
14
IN+
V
SS
IN-
OUT
V
DD
OUTA
INA-
INA+
INB+
INB-
OUTB
OUTC
INC-
INC+
IND+
IND-
OUTD
Comparator Noninverting Input
Negative Supply Voltage
Comparator Inverting Input
Comparator Output
Positive Supply Voltage. Bypass with a 0.1µF capacitor to GND.
Comparator A Output
Comparator A Inverting Input
Comparator A Noninverting Input
Comparator B Noninverting Input
Comparator B Inverting Input
Comparator B Output
Comparator C Output
Comparator C Inverting Input
Comparator C Noninverting Input
Comparator D Noninverting Input
Comparator D Inverting Input
Comparator D Output
FUNCTION
MAX9021/MAX9022/MAX9024
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, t
PD
, typi-
cally 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 out-
put switching, even with slow-moving input signals.
tor’s output sets the trip voltage. Therefore, the trip volt-
age is related to the output voltage.
These comparators have 4mV internal hysteresis.
Additional hysteresis can be generated with two resis-
tors, using positive feedback (Figure 1). Use the follow-
ing procedure to calculate resistor values:
1) Find the trip points of the comparator using these for-
mulas:
V
TH
= V
REF
+ ((V
DD
- V
REF
)R2) / (R1 + R2)
V
TL
= V
REF
(1 - (R2 / (R1 + R2))
where V
TH
is the threshold voltage at which the com-
parator switches its output from high to low as V
IN
rises above the trip point. V
TL
is the threshold volt-
age at which the comparator switches its output from
low to high as V
IN
drops below the trip point.
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-
_______________________________________________________________________________________
5
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