19-0450; Rev 3; 2/03
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
The MAX971–MAX974 and MAX981–MAX984 single/
dual/quad low-voltage comparators feature the lowest
power consumption available. These micropower
devices draw less than 4µA supply current over
temperature (MAX971/MAX972/MAX981/MAX982), and
include an internal 1.182V ±1% (MAX971/MAX973/
MAX974) or ±2% (MAX981–MAX984) voltage reference
and programmable hysteresis.
Ideal for 3V or 5V single-supply applications, these
devices operate from a single 2.5V to 11V supply (or
±1.25V to ±5.5V dual supplies), and each comparator’s
input voltage ranges from the negative supply rail to within
1.3V of the positive supply.
♦ Available in Ultra-Small Packages:
UCSP™ (MAX972)
µMAX (MAX9_1/MAX9_2/MAX9_3)
♦ Ultra-Low Quiescent Current (4µA, max)
Over Extended Temp Range (MAX971/MAX981)
♦ Power Supplies:
Single 2.5V to 11V
Dual ±1.25V to ±5.5V
♦ Input Voltage Range Includes Negative Supply
♦ Internal Bandgap Reference
1.182V ±1% (MAX97_)
1.182V ±2% (MAX98_)
♦ 12µs Propagation Delay (10mV Overdrive)
♦ Output Has Separate GND Pin (MAX9_1/MAX9_4)
Applications
Battery-Powered
Systems
Window Comparators
Threshold Detectors
Oscillator Circuits
Level Translators
Ordering Information
PART
TEMP RANGE
0°C to +70°C
8 SO
MAX971CUA
0°C to +70°C
8 µMAX
1%
1
Yes
8-Pin
DIP/SO/µMAX
MAX972
None
2
No
8-Pin UCSP/
DIP/SO/µMAX
3 IN+
MAX973
1%
2
Yes
8-Pin
DIP/SO/µMAX
4 IN-
PACKAGE
INTERNAL
HYSTERESIS
MAX971CSA
COMPARATORS
PER
PACKAGE
8 Plastic Dip
INTERNAL
PRECISION
REFERENCE
0°C to +70°C
MAX971
MAX974
1%
4
No
16-Pin DIP/SO
MAX981
2%
1
Yes
8-Pin
DIP/SO/µMAX
MAX982
2%
2
Yes
8-Pin
DIP/SO/µMAX
MAX983
2%
2
Yes
8-Pin
DIP/SO/µMAX
MAX984
2%
4
No
16-Pin DIP/SO
PIN-PACKAGE
MAX971CPA
PART
The single MAX971/MAX981 and the dual MAX973/
MAX982/MAX983 provide a unique, simple method for
adding hysteresis without feedback or complicated
equations, simply by using the HYST pin plus two
resistors.
The MAX971–MAX974 and MAX981–MAX984’s opendrain outputs permit wire-ORed configurations. Thanks to
an 11V output range and separate GND pin for the output
transistor (MAX971/MAX974, MAX981/MAX984), these
devices are ideal for level translators and bipolar to singleended converters. For similar devices with complementary
output stages, see the MAX921–MAX924 (1% reference)
and the MAX931–MAX934 (2% reference).
Features
Ordering Information continued at end of data sheet.
Typical Operating Circuit
VIN
7
V+
OUT 8
5 HYST
MAX971
MAX981
6 REF
V2
GND
1
THRESHOLD DETECTOR
UCSP is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________________________________ 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.
MAX971–MAX974/MAX981–MAX984
General Description
MAX971–MAX974/MAX981–MAX984
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
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
OUT_ ................................................................50mA
Voltage: REF ....................................(V+ + 0.3V) to (V- - 0.3V)
OUT_ (MAX9_1/9_4)..................12V to (GND - 0.3V)
(MAX9_2/9_3).......................12V to (V- - 0.3V)
OUT_ Short-Circuit Duration ..................................Continuous
Continuous Power Dissipation (TA = +70°C)
8-Bump UCSP (derate 4.7mW/°C above +70°C) ........379mW
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
16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)..842mW
16-Pin SO (derate 8.70mW/°C above +70°C) ................696mW
Operating Temperature Ranges
MAX97_C_ _/MAX98_C_ _ ..................................0°C to +70°C
MAX97_E_ _/MAX98_E_ _ ...............................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Bump Temperature (soldering)
Reflow ..........................................................................+235°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—5V OPERATION
(V+ = 5V, V- = GND = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
POWER REQUIREMENTS
Supply Voltage Range
(Note 2)
Output Voltage Range
MAX9_1,
HYST = REF
Supply Current
IN+ = IN- +
100mV
11
V
0
11
V
TA = +25°C
2.5
3.2
2.5
3.2
C/E temp ranges
4
TA = +25°C
MAX972
C/E temp ranges
MAX982/
MAX9_3,
HYST = REF
MAX9_4
2.5
4
TA = +25°C
3.1
C/E temp ranges
4.5
µA
6
TA = +25°C
5.5
C/E temp ranges
6.5
8.5
COMPARATOR
Input Offset Voltage
VCM = 2.5V
Input Leakage Current (IN-, IN+)
IN+ = IN- = 2.5V
Input Leakage Current (HYST)
MAX9_1/MAX982/MAX9_3
C/E temp ranges
±0.01
±10
mV
±5
nA
±0.02
Input Common-Mode Voltage
Range
V-
nA
V+ - 1.3
V
Common-Mode Rejection Ratio
V- to (V+ - 1.3V)
0.1
1.0
mV/V
Power-Supply Rejection Ratio
V+ = 2.5V to 11V
0.1
1.0
mV/V
Voltage Noise
100Hz to 100kHz
Hysteresis Input Voltage Range
MAX9_1/MAX982/MAX9_3
Response Time (High-to-Low
Transition)
TA = +25°C, 100pF load,
1MΩ pullup to V+
Response Time (Low-to-High
Transition) (Note 3)
TA = +25°C, 100pF load, 1MΩ pullup to V+
2
20
REF - 0.05
µVRMS
REF
Overdrive = 10mV
12
Overdrive = 100mV
4
300
_______________________________________________________________________________________
V
µs
µs
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
(V+ = 5V, V- = GND = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
Output Low Voltage
Output Leakage Current
CONDITIONS
MIN
TYP
MAX
UNITS
MAX9_2/MAX9_3, IOUT = 1.8mA
V- + 0.4
MAX9_1/MAX9_4, IOUT = 1.8mA
GND
+ 0.4
V
100
nA
VOUT = 11V
REFERENCE (MAX9_1/MAX982/MAX9_3/MAX9_4 ONLY)
MAX971/MAX973/
MAX974
Reference Voltage
MAX981–MAX984
Source Current
Sink Current
Voltage Noise
C temp range
1%
1.170
E temp range
2%
1.158
C temp range
2%
1.158
E temp range
3%
1.147
TA = +25°C
15
C/E temp ranges
6
TA = +25°C
8
C/E temp ranges
4
100Hz to 100kHz
1.182
1.194
1.206
1.182
1.206
V
1.217
25
µA
15
µA
100
µVRMS
ELECTRICAL CHARACTERISTICS—3V OPERATION
(V+ = 3V, V- = GND = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
MAX
2.4
3.0
UNITS
POWER REQUIREMENTS
MAX9_1
HYST = REF,
IN+ = (IN- +
100mV)
Supply Current
MAX972
MAX982/
MAX9_3
MAX9_4
TA = +25°C
C/E temp ranges
3.8
TA = +25°C
2.4
3.0
3.4
4.3
5.2
6.2
C/E temp ranges
3.8
TA = +25°C
C/E temp ranges
µA
5.8
TA = +25°C
C/E temp ranges
8.0
COMPARATOR
Input Offset Voltage
VCM = 1.5V
Input Leakage Current (IN-, IN+)
IN+ = IN- = 1.5V
Input Leakage Current (HYST)
Input Common-Mode Voltage
Range
Common-Mode Rejection Ratio
MAX9_1/MAX982/MAX9_3
V- to (V+ - 1.3V)
Power-Supply Rejection Ratio
Voltage Noise
Hysteresis Input Voltage Range
MAX9_1/MAX982/MAX9_3
C/E temp ranges
±0.01
±10
mV
±5
nA
±0.02
V-
nA
V+ - 1.3
V
0.2
1
mV/V
V+ = 2.5V to 11V
0.1
1
100Hz to 100kHz
20
REF - 0.05
mV/V
µVRMS
REF
V
_______________________________________________________________________________________
3
MAX971–MAX974/MAX981–MAX984
ELECTRICAL CHARACTERISTICS—5V OPERATION (continued)
MAX971–MAX974/MAX981–MAX984
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
ELECTRICAL CHARACTERISTICS—3V OPERATION (continued)
(V+ = 3V, V- = GND = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
CONDITIONS
MIN
12
Overdrive = 100mV
4
Response Time (High-to-Low
Transition)
TA = +25°C, 100pF load,
1MΩ pullup to V+
Response Time (Low-to-High
Transition) (Note 3)
TA = +25°C, 100pF load, 1MΩ pullup to V+
Output Low Voltage
Output Leakage Current
TYP
Overdrive = 10mV
MAX
UNITS
µs
300
µs
MAX9_2/MAX9_3, IOUT = 0.8mA
V- + 0.4
MAX9_1/MAX9_4, IOUT = 0.8mA
GND + 0.4
VOUT = 11V
100
V
nA
REFERENCE
MAX971/MAX973/
MAX974
Reference Voltage
MAX981–MAX984
Source Current
Sink Current
Voltage Noise
C temp range
1%
1.170
E temp range
2%
1.158
C temp range
2%
1.158
E temp range
3%
1.147
TA = +25°C
15
C/E temp ranges
6
TA = +25°C
8
C/E temp ranges
4
100Hz to 100kHz
1.182
1.194
1.206
1.182
1.206
V
1.217
25
15
100
µA
µA
µVRMS
Note 1: The MAX972EBL is 100% tested at TA = +25°C. Temperature limits are guaranteed by design.
Note 2: MAX974/MAX984 comparators work below 2.5V; see Low-Voltage Operation section for more details.
Note 3: Low-to-high response time is the result of the 1MΩ pullup and the 100pF capacitive load, based on three time constants.
A faster response time is achieved with a smaller RC.
4
_______________________________________________________________________________________
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
REFERENCE OUTPUT VOLTAGE vs.
OUTPUT LOAD CURRENT
1.0
0.5
1.180
SOURCE
1.175
1.170
1.165
V+ = 5V
OR
V+ = 3V
1.160
4
8
16
12
1.17
1.16
1.15
10
5
20
15
25
30
-60 -40 -20 0
20 40 60 80 100 120 140
MAX9_1
SUPPLY CURRENT vs.
TEMPERATURE
MAX972
SUPPLY CURRENT vs. TEMPERATURE
MAX982/MAX9_3
SUPPLY CURRENT vs. TEMPERATURE
3.0
V+ = 3V, V- = 0V
4.0
3.5
V+ = 10V, V- = 0V
3.0
2.5
V+ = 5V, V- = 0V
5.0
4.5
2.0
V+ = 5V, V- = 0V
3.5
3.0
2.5
V+ = 3V, V- = 0V
1.5
2.0
20
4.0
V+ = 3V, V- = 0V
V+ = 5V, V- = 0V
-20
MAX971-4/981-4 TOC6
IN+ = (IN- + 100mV)
SUPPLY CURRENT (µA)
MAX971-4/981-4 TOC4
V+ = 5V, V- = - 5V
4.5
2.5
60
100
2.0
-60
140
-20
20
100
60
140
-60
-20
20
60
100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
MAX9_4
SUPPLY CURRENT vs. TEMPERATURE
MAX9_4
SUPPLY CURRENT vs.
LOW SUPPLY VOLTAGES
MAX9_1/MAX982/MAX9_3
HYSTERESIS CONTROL
V+ = 5V, V- = -5V
6
V+ = 5V, V- = 0V
5
4
1
0.1
20
60
TEMPERATURE (°C)
20
0
NO CHANGE
-20
OUTPUT LOW
-60
3
-20
OUTPUT HIGH
40
-40
V+ = 3V, V- = 0V
-60
60
140
MAX971-4/981-4 TOC9
8
80
IN+ - IN- (V)
9
10
MAX971-4/981-4 TOC8
IN+ = (IN- + 100mV)
SUPPLY CURRENT (µA)
MAX971-4/981-4 TOC7
10
SUPPLY CURRENT (µA)
1.18
TEMPERATURE (°C)
4.0
-60
COMMERCIAL
TEMP RANGE
1.19
OUTPUT LOAD CURRENT (µA)
IN+ = IN- + 100mV
3.5
EXTENDED TEMP RANGE
1.20
LOAD CURRENT (mA)
4.5
7
1.21
1.14
0
20
SUPPLY CURRENT (µA)
0
MAX971-4/981-4 TOC3
1.185
1.22
1.155
0
SUPPLY CURRENT (µA)
SINK
MAX971-4/981-4 TOC5
VOL (V)
V+ = 3V
1.5
1.190
REFERENCE VOLTAGE (V)
2.0
MAX971/MAX973/MAX974
REFERENCE VOLTAGE vs. TEMPERATURE
MAX971-4/981-4 TOC2
V+ = 5V
REFERENCE OUTPUT VOLTAGE (V)
2.5
MAX971-4/981-4-TOC1
OUTPUT VOLTAGE LOW
vs. LOAD CURRENT
100
140
-80
0.01
1.0
1.5
2.0
SINGLE-SUPPLY VOLTAGE (V)
2.5
0
10
20
30
40
50
VREF - VHYST (mV)
_______________________________________________________________________________________
5
MAX971–MAX974/MAX981–MAX984
__________________________________________Typical Operating Characteristics
(V+ = 5V, V- = GND = 0V, TA = +25°C, unless otherwise noted.)
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
Typical Operating Characteristics (continued)
(V+ = 5V, V- = GND = 0V, TA = +25°C, unless otherwise noted.)
3.0
2.5
2.0
1.5
1.0
14
VOHL
12
0
5
4
10mV
3
100mV
2
10
1
8
0
6
4
0.5
20mV
50mV
100
0
2
0.3
0
RESPONSE TIME
AT LOW SUPPLY VOLTAGES (VOHL)
100
-20mV
10
40
60
80
100
-2
2
6
10
14
LOAD CAPACITANCE (nF)
RESPONSE TIME (µs)
MAX9_4
SINK CURRENT
AT LOW SUPPLY VOLTAGES
SHORT-CIRCUIT SINK CURRENT
vs. SUPPLY VOLTAGE
MAX971-4/981-4 TOC14
100
CURRENT (mA)
RPULLUP = 10kΩ
MAX971-4/981-4 TOC13
1000
20
10
1
25
OUT CONNECTED TO V+
GND CONNECTED TO V20
18
MAX971-4/981-4 TOC15
0.2
0.1
-0.2 -0.1
0
IN+ INPUT VOLTAGE (mV)
SINK CURRENT (mA)
-0.3
RESPONSE TIME (µs)
MAX971-4/981-4 TOC11
10µF
3.5
V- = 0V
16
VOUT (V)
V0
VIN (mV)
100kΩ
RESPONSE TIME FOR VARIOUS
INPUT OVERDRIVES (VOHL)
18
RESPONSE TIME (µs)
+5V
10kΩ
4.0
OUTPUT VOLTAGE (V)
MAX971-4/981-4 TOC10
5.0
4.5
RESPONSE TIME vs.
LOAD CAPACITANCE
MAX971-4/981-4 TOC12
MAX9_1/MAX972/MAX9_4
TRANSFER FUNCTION
15
10
5
-100mV
SINK CURRENT AT VOUT = 0.4V
1
0.1
1.0
1.2
1.4
1.6
1.8
2.0
2.2
SINGLE-SUPPLY VOLTAGE (V)
6
2.4
1.0
1.5
2.0
SINGLE-SUPPLY VOLTAGE (V)
2.5
0
5
0
TOTAL SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
10
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
PIN
MAX971/
MAX981
MAX972
MAX982
MAX973/
MAX983
NAME
FUNCTION
DIP/SO/
µMAX
DIP/SO/
µMAX
UCSP
DIP/SO/
µMAX
DIP/SO/
µMAX
1
—
—
—
—
GND
Ground. Connect to V- for single-supply operation.
2
2
C2
2
2
V-
Negative Supply. Connect to GND for single-supply
operation (MAX9_1).
3
—
—
—
—
IN+
Noninverting Comparator Input
4
—
—
—
—
IN-
Inverting Comparator Input
5
—
—
5
5
HYST
6
—
—
6
6
REF
Reference Output. 1.182V with respect to V-.
7
7
A2
7
7
V+
Positive Supply
8
—
—
—
—
OUT
—
1
A1
1
1
OUTA
—
3
C1
3
3
INA+
Noninverting Input of Comparator A
—
4
B1
—
—
INA-
Inverting Input of Comparator A
—
5
B3
—
4
INB-
Inverting Input of Comparator B
—
6
C3
4
—
INB+
Noninverting Input of Comparator B
—
8
A3
8
8
OUTB
Comparator B Open-Drain Output. Sinks current to V-.
Hysteresis Input. Connect to REF if not used. Input
voltage range is from VREF to (VREF - 50mV).
Comparator Output. Sinks current to GND.
Comparator A Open-Drain Output. Sinks current to V-.
_______________________________________________________________________________________
7
MAX971–MAX974/MAX981–MAX984
Pin Description
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
MAX971–MAX974/MAX981–MAX984
Pin Description (continued)
PIN
MAX974
MAX984
8
NAME
FUNCTION
1
OUTB
Comparator B Open-Drain Output. Sinks current to GND.
2
OUTA
Comparator A Open-Drain Output. Sinks current to GND.
3
V+
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-
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 Open-Drain Output. Sinks current to GND.
16
OUTC
Comparator C Open-Drain Output. Sinks current to GND.
Positive Supply
Negative Supply. Connect to ground for single-supply operation.
_______________________________________________________________________________________
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
Power-Supply and Input Signal Ranges
The MAX971–MAX974/MAX981–MAX984 comprise
various combinations of a micropower 1.182V reference
and micropower comparators. The Typical Operating
Circuit shows the MAX971/MAX981 configuration, and
Figures 1a–1d show the MAX9_2–MAX9_4 configurations.
Internal hysteresis in the MAX9_1, MAX982, and
MAX9_3 provides the easiest method for implementing
hysteresis. It also produces faster hysteresis action and
consumes much less current than circuits using external
positive feedback.
This family of devices operates from a single 2.5V to 11V
power supply. The MAX9_1 and MAX9_4 have a
separate ground for the output driver, allowing operation
with dual supplies ranging from ±1.25V to ±5.5V.
Connect V- to GND when operating the MAX9_1 or
MAX9_4 from a single supply. The maximum total supply
voltage in this case is still 11V.
MAX972
1 (A1) OUTA
2 (C2) V-
OUTB 8 (A3)
V+ 7 (A2)
3 (C1) INA+
INB+ 6 (C3)
4 (B1) INA-
INB- 5 (B3)
For proper comparator operation, the input signal can
range from the negative supply (V-) to within one volt of
the positive supply (V+ - 1V). The guaranteed commonmode input voltage range extends from V- to (V+ 1.3V). The inputs can be taken above and below the
supply rails by up to 300mV without damage.
MAX9_3
1 OUTA
2 V-
OUTB 8
V+ 7
3 INA+
REF 6
4 INB-
HYST 5
V-
Figure 1c. MAX973/MAX983 Functional Diagram
(Window Comparator)
( ) BUMPS FOR THE UCSP
Figure 1a. MAX972 Functional Diagram
1 OUTB
2 OUTA
MAX982
1 OUTA
2 V-
MAX9_4
OUTC 16
OUTD 15
3 V+
GND 14
4 INA-
IND+ 13
5 INA+
IND- 12
6 INB-
INC+ 11
7 INB+
INC- 10
8 REF
V- 9
OUTB 8
V+ 7
3 INA+
REF 6
4 INB+
HYST 5
V-
Figure 1b. MAX982 Functional Diagram
Figure 1d. MAX974/MAX984 Functional Diagram
_______________________________________________________________________________________
9
MAX971–MAX974/MAX981–MAX984
Detailed Description
MAX971–MAX974/MAX981–MAX984
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
THRESHOLDS
IN+
INVREF - VHYST
HYSTERESIS
VHB
The negative supply does not affect the output sink
current. The positive supply provides gate drive for the
output N-channel MOSFET and heavily influences the
output current capability, especially at low supply
voltages (see Typical Operating Characteristics section).
The MAX9_2 and MAX9_3 have no GND pin, and their
outputs sink current to V-.
BAND
Voltage Reference
The internal bandgap voltage reference has an output
of 1.182V above V-. Note that the REF voltage is
referenced to V-, not to GND. Its accuracy is ±1%
(MAX971/MAX973/MAX974) or ±2% (MAX981–MAX984)
in the 0°C to +70°C range. The REF output is typically
capable of sourcing 25µA and sinking 15µA. Do not
bypass the REF output.
OUT
Noise Considerations
Figure 2. Threshold Hysteresis Band
Low-Voltage Operation: V+ = 1V
(MAX9_4 Only)
The guaranteed minimum operating voltage is 2.5V (or
±1.25V). As the total supply voltage falls below 2.5V,
performance degrades and the supply current falls. The
reference will not function below about 2.2V, although
the comparators will continue to operate with a total
supply voltage as low as 1V. While the MAX9_4 has
comparators that may be used at supply voltages below
2V, the MAX9_1/MAX9_2/MAX9_3 may not be used with
supply voltages below 2.5V.
At low supply voltages, the comparators’ output sink
capability is reduced and the propagation delay
increases (see Typical Operating Characteristics). The
useful input voltage range extends from the negative
supply to a little under 1V below the positive supply,
which is slightly closer to the positive rail than when the
device operates from higher supply voltages. Test your
prototype over the full temperature and supply-voltage
range if you anticipate operation below 2.5V.
Although the comparators have a very high gain, useful
gain is limited by noise. This is shown in the Transfer
Function graph (see Typical Operating Characteristics).
As the input voltage approaches the comparator’s
offset, the output begins to bounce back and forth; this
peaks when VIN = VOS. (The lowpass filter shown on the
graph averages out the bouncing, making the transfer
function easy to observe.) Consequently, the
comparator has an effective wideband peak-to-peak
noise of around 300µV. The voltage reference has
peak-to-peak noise approaching 1mV. Thus, when a
comparator is used with the reference, the combined
peak-to-peak noise is about 1mV. This, of course, is
much higher than the RMS noise of the individual
components. Take care in your layout to avoid
capacitive coupling from any output to the reference
pin. Crosstalk can significantly increase the actual
noise of the reference.
IREF
Comparator Output
With 100mV of overdrive, propagation delay is typically
3µs. The Typical Operating Characteristics show the
propagation delay for various overdrive levels. The
open-drain outputs are intended for wire-ORed and
level-shifting applications. The maximum output voltage
is 11V above V-, and may be applied even when no
supply voltage is present (V+ = V-).
The MAX9_1 and MAX9_4 outputs sink current to GND,
making these devices ideal for bipolar to single-ended
conversion and level-shifting applications.
10
6
REF
2.5V TO 11V
7
V+
MAX9_1
MAX982
MAX9_3
R1
5
R2
HYST
V2
Figure 3. Programming the HYST Pin
______________________________________________________________________________________
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
V+
Hysteresis
RH
Hysteresis increases the comparators’ noise margin by
increasing the upper threshold and decreasing the
lower threshold (Figure 2).
Hysteresis (MAX9_1/MAX982/MAX9_3)
To add hysteresis to the MAX9_1, MAX982, or MAX9_3,
connect resistor R1 between REF and HYST, and
connect resistor R2 between HYST and V- (Figure 3). If
no hysteresis is required, connect HYST to REF. When
hysteresis is added, the upper threshold increases by
the same amount that the lower threshold decreases.
The hysteresis band (the difference between the upper
and lower thresholds, VHB) is approximately equal to
twice the voltage between REF and HYST. The HYST
input can be adjusted to a maximum voltage of REF
and to a minimum voltage of (REF - 50mV). The
maximum difference between REF and HYST (50mV)
will therefore produce a 100mV (max) hysteresis band.
Use the following equations to determine R1 and R2:
VHB
R1 =
2 × IREF
(
)
VHB
1.182 –
2
R2 =
IREF
where I REF (the current sourced by the reference)
should not exceed the REF source capability, and
should be significantly larger than the HYST input
current. IREF values between 0.1µA and 4µA are usually
appropriate. If 2.4MΩ is chosen for R2 (IREF = 0.5µA),
the equation for R1 and VHB can be approximated as:
R1 (kΩ) = VHB (mV)
When hysteresis is obtained in this manner for the
MAX982/MAX9_3, the same hysteresis applies to both
comparators.
Hysteresis (MAX972/MAX9_4)
Hysteresis can be implemented with any comparator
using positive feedback, as shown in Figure 4. This
approach generally draws more current than circuits
using the HYST pin on the MAX9_1/MAX982/MAX9_3,
and the high feedback impedance slows hysteresis. In
addition, because the output does not source current,
any increase in the upper threshold is dependent on
the load or pullup resistor on the output.
RPULLUP
VIN
V+
MAX9_4 V-
OUT
GND
VREF
Figure 4. External Hysteresis
Board Layout and Bypassing
Power-supply bypass capacitors are not needed if the
supply impedance is low, but 100nF bypass capacitors
should be used when the supply impedance is high or
when the supply leads are long. Minimize signal lead
lengths to reduce stray capacitance between the input
and output that might cause instability. Do not bypass
the reference output.
Window Detector
The MAX9_3 is ideal for making window detectors
(undervoltage/overvoltage detectors). The schematic is
shown in Figure 5, with component values selected for a
4.5V undervoltage threshold and a 5.5V overvoltage
threshold. Choose different thresholds by changing the
values of R1, R2, and R3. To prevent chatter at the
output when the supply voltage is close to a threshold,
hysteresis has been added using R4 and R5. Taken
alone, OUTA would provide an active-low undervoltage
indication, and OUTB would give an active-low
overvoltage indication. Wired-ORing the two outputs
provides an active-high, power-good signal.
The design procedure is as follows:
1) Choose the required hysteresis level and calculate
values for R4 and R5 according to the formulas in
the Hysteresis (MAX9_1/MAX982/MAX9_3) section.
In this example, ±5mV of hysteresis has been added
at the comparator input (VH = VHB/2). This means
that the hysteresis apparent at V IN will be larger
because of the input resistor divider.
______________________________________________________________________________________
11
MAX971–MAX974/MAX981–MAX984
__________Applications Information
MAX971–MAX974/MAX981–MAX984
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
2) Select R1. The leakage current into INB- is normally
under 1nA, so the current through R1 should exceed
100nA for the thresholds to be accurate. R1 values
up to about 10MΩ can be used, but values in the
100kΩ to 1MΩ range are usually easier to deal with.
In this example, choose R1 = 294kΩ.
VIN
VOTH = 5.5V
VUTH = 4.5V
R3
1MΩ
3) Calculate R2 + R3. The overvoltage threshold
should be 5.5V when V IN is rising. The design
equation is as follows:
VOTH
R2 + R3 = R1 ×
− 1
VREF + VH
5V
7
V+
3 INA+
OUTA 1
5 HYST
5.5
= 294kΩ ×
− 1
(1.182 + 0.005)
R2
62.2kΩ
R5
10kΩ
R4
2.4MΩ
6 REF
= 1.068MΩ
OUTB 8
4) Calculate R2. The undervoltage threshold should be
4.5V when VIN is falling. The design equation is as
follows:
R2 = (R1 + R2 + R 3) ×
4 INBR1
294kΩ
POWER GOOD
V-
MAX9_3
2
(VREF − VH )
− R1
VUTH
= (294kΩ + 1.068MΩ) ×
(1.182 − 0.005)
4.5
Figure 5. Window Detector
− 294kΩ
= 62.2kΩ
Battery Switchover Circuit
Choose R2 = 61.9kΩ (1% s tan dard value).
5) Calculate R3:
R3 = (R2 + R3 ) − R2
= 1.068MΩ − 61.9 kΩ
= 1.006MΩ
Choose R3 = 1MΩ (1% standard value)
6) Verify the resistor values. The equations are as
follows, evaluated for the above example:
Overvoltage Threshold:
(R1 + R2 + R3)
VOTH = (VREF + VH ) ×
R1
= 5.474V
Undervoltage Threshold :
(R1 + R2 + R3)
VUTH = (VREF − VH ) ×
(R1 + R2)
The switchover from line-powered DC to a backup
battery is often accomplished with diodes. But this
simple method is sometimes unacceptable, due to the
voltage drop and associated power loss across the
diode in series with the battery. Figure 6’s circuit
replaces the diode with a P-channel MOSFET
controlled by one of the MAX9_3 comparator outputs.
When the DC wall adapter drops below 4V (determined
by R1 and R2), OUTA goes low, turning on Q1.
Comparator B is used to measure the battery voltage,
and gives a “low-battery” indication when the battery
drops below 3.6V.
Level-Shifter
Figure 7 shows a circuit to shift from bipolar ±5V inputs
to single-ended 5V outputs. The 10kΩ resistors protect
the comparator inputs, and do not materially affect the
circuit’s operation.
= 4.484V
where the hysteresis voltage VH = VREF ×
12
1MΩ
R5
.
R4
______________________________________________________________________________________
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
3.3V
3
WALL
ADAPTER
V+
9V DC
10kΩ
STEP-DOWN
REGULATOR
3.3V
LOGIC
SUPPLY
Q1
5 INA+
VINA
MAX974
MAX984
OUTA 2
4
INA-
1MΩ
10kΩ
7
V+
BATTERY
(4 CELLS)
7 INB+
VINB
OUTB 1
MAX973
MAX983
953kΩ
10kΩ
6 INB-
4 INB-
10kΩ
OUTB 8
470kΩ
VINC
11 INC+
LOW BATT
OUTC 16
1 OUTA
R1
110kΩ
10 INC-
DC OK
10kΩ
VIND
3 INA+
13 IND+
OUTD 15
REF 6
20kΩ
R2
47kΩ
12 INDREF
HYST 5
V2
2.4MΩ
GND
14
8
N.C.
V9
-5V
Figure 6. Battery Switchover Circuit
Figure 7. Level Shifter: ±5V Input to Single-Ended 3.3V Output
UCSP Applications Information
For the latest application details on UCSP contruction,
dimensions, tape carrier information, printed circuit
board techniques, bump-pad layout and
recommended reflow temperature profile as well as the
latest information on reliability testing results, go to
Maxim’s web site at www.maxim-ic.com/ucsp to find
the Application Note: UCSP–A Wafer-Level Chip-Scale
Package.
______________________________________________________________________________________
13
MAX971–MAX974/MAX981–MAX984
5V
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
MAX971–MAX974/MAX981–MAX984
Pin Configurations
TOP VIEW
GND
1
V- 2
MAX971
MAX981
IN+ 3
IN- 4
8
OUT
7
V+
6
REF
INA+ 3
5
HYST
INA- 4
OUTA
1
V- 2
DIP/SO/µMAX
MAX972
8
OUTB
7
V+
6
INB+
INA+ 3
5
INB-
INB+ 4
OUTA
1
V- 2
MAX982
8
OUTB
7
V+
6
REF
5
HYST
DIP/SO/µMAX
DIP/SO/µMAX
TOP VIEW
(BUMPS ON BOTTOM)
A
1
2
3
OUTA
V+
OUTB
OUTA
1
V- 2
B
INA-
MAX972
INB-
INA+ 3
MAX973
MAX983
INB- 4
C
INA+
V-
UCSP
INB+
8
OUTB
OUTB 1
16 OUTC
7
V+
OUTA 2
15 OUTD
6
REF
5
HYST
V+ 3
INA- 4
INA+ 5
DIP/SO/µMAX
14 GND
MAX974
MAX984
12 IND-
INB- 6
11 INC+
INB+ 7
10 INC-
REF 8
9
DIP/Narrow SO
14
13 IND+
______________________________________________________________________________________
V-
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
PART
PART
TEMP RANGE
PIN-PACKAGE
TEMP RANGE
PIN-PACKAGE
MAX971EPA
-40°C to +85°C
8 Plastic Dip
MAX981CSA
MAX971ESA
-40°C to +85°C
8 SO
MAX981CUA
0°C to +70°C
MAX972CPA
0°C to +70°C
8 Plastic Dip
MAX981EPA
-40°C to +85°C
8 Plastic Dip
MAX972CSA
0°C to +70°C
8 SO
MAX981ESA
-40°C to +85°C
8 SO
8 µMAX
MAX982CPA
0°C to +70°C
8 Plastic Dip
8 SO
MAX972CUA
0°C to +70°C
0°C to +70°C
8 SO
8 µMAX
MAX972EBL-T*
-40°C to +85°C
8 UCSP-8
MAX982CSA
0°C to +70°C
MAX972EPA
-40°C to +85°C
8 Plastic Dip
MAX982CUA
0°C to +70°C
-40°C to +85°C
8 Plastic Dip
8 SO
8 µMAX
MAX972ESA
-40°C to +85°C
8 SO
MAX982EPA
MAX973CPA
0°C to +70°C
8 Plastic Dip
MAX982ESA
-40°C to +85°C
MAX973CSA
0°C to +70°C
8 SO
MAX983CPA
0°C to +70°C
8 Plastic Dip
MAX973CUA
0°C to +70°C
8 µMAX
MAX983CSA
0°C to +70°C
8 SO
MAX973EPA
-40°C to +85°C
8 Plastic Dip
MAX983CUA
0°C to +70°C
MAX973ESA
-40°C to +85°C
8 SO
MAX983EPA
-40°C to +85°C
8 Plastic Dip
MAX974CPE
0°C to +70°C
16 Plastic Dip
MAX983ESA
-40°C to +85°C
8 SO
8 µMAX
MAX974CSE
0°C to +70°C
16 Narrow SO
MAX984CPE
0°C to +70°C
16 Plastic Dip
MAX974EPE
-40°C to +85°C
16 Plastic Dip
MAX984CSE
0°C to +70°C
16 Narrow SO
MAX974ESE
-40°C to +85°C
16 Narrow SO
MAX984EPE
-40°C to +85°C
16 Plastic Dip
MAX981CPA
0°C to +70°C
8 Plastic Dip
MAX984ESE
-40°C to +85°C
16 Narrow SO
*UCSP top mark is “ABC.”
___________________Chip Information
MAX971/MAX972/MAX973/MAX981/MAX982/MAX984
TRANSISTOR COUNT: 164
MAX974/MAX984 TRANSISTOR COUNT: 267
______________________________________________________________________________________
15
MAX971–MAX974/MAX981–MAX984
Ordering Information (continued)
Package Information
4X S
8
8
E
ÿ 0.50±0.1
H
MIN
0.002
0.030
0.6±0.1
L
1
α
0.6±0.1
S
BOTTOM VIEW
D
MAX
0.043
0.006
0.037
0.05
0.75
1.10
0.15
0.95
0.25
0.36
0.13
0.18
2.95
3.05
0.65 BSC
2.95
3.05
4.78
5.03
0.41
0.66
0∞
6∞
0.5250 BSC
0.010
0.014
0.005
0.007
0.116
0.120
0.0256 BSC
0.116
0.120
0.188
0.198
0.016
0.026
6∞
0∞
0.0207 BSC
c
D
e
E
H
1
MILLIMETERS
MAX
MIN
INCHES
DIM
A
A1
A2
b
8LUMAXD.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.)
TOP VIEW
A1
A2
A
α
c
e
L
b
SIDE VIEW
FRONT VIEW
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, 8L uMAX/uSOP
APPROVAL
DOCUMENT CONTROL NO.
21-0036
DIM
A
A1
B
C
e
E
H
L
N
E
H
INCHES
MILLIMETERS
MAX
MIN
0.069
0.053
0.010
0.004
0.014
0.019
0.007
0.010
0.050 BSC
0.150
0.157
0.228
0.244
0.016
0.050
MAX
MIN
1.35
1.75
0.10
0.25
0.35
0.49
0.19
0.25
1.27 BSC
3.80
4.00
5.80
6.20
0.40
REV.
1
J
1
SOICN .EPS
MAX971–MAX974/MAX981–MAX984
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
1.27
VARIATIONS:
1
INCHES
TOP VIEW
DIM
D
D
D
MIN
0.189
0.337
0.386
MAX
0.197
0.344
0.394
MILLIMETERS
MIN
4.80
8.55
9.80
MAX
5.00
8.75
10.00
N MS012
8
AA
14
AB
16
AC
D
A
B
e
C
0∞-8∞
A1
L
FRONT VIEW
SIDE VIEW
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, .150" SOIC
APPROVAL
DOCUMENT CONTROL NO.
21-0041
16
REV.
B
1
1
______________________________________________________________________________________
Ultra Low-Power, Open-Drain,
Single/Dual-Supply Comparators
9LUCSP, 3x3.EPS
PDIPN.EPS
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 17
© 2003 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX971–MAX974/MAX981–MAX984
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.)
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