Ij

19-0450; Rev 3; 2/03
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
General Description
Features
o Available in Ultra-Small Packages:
The MAX971?MAX974 and MAX981?MAX984 single/
dual/quad low-voltage comparators feature the lowest
UCSPTM (MAX972)
power consumption available. These micropower
?MAX (MAX9_1/MAX9_2/MAX9_3)
d e v i c e s draw less than 4?A supply current over
o Ultra-Low Quiescent Current (4?A, max)
temperature (MAX971/MAX972/MAX981/MAX982), and
Over Extended Temp Range (MAX971/MAX981)
include an internal 1.182V ?1% (MAX971/MAX973/
o Power Supplies:
MAX974) or ?2% (MAX981?MAX984) voltage reference
Single 2.5V to 11V
and programmable hysteresis.
Dual ?1.25V to ?5.5V
Ideal for 3V or 5V single-supply applications, these
o Input Voltage Range Includes Negative Supply
devices operate from a single 2.5V to 11V supply (or
?1.25V to ?5.5V dual supplies), and each comparator's
o Internal Bandgap Reference
input voltage ranges from the negative supply rail to within
1.182V ?1% (MAX97_)
1.3V of the positive supply.
1.182V ?2% (MAX98_)
The single MAX971/MAX981 and the dual MAX973/
o 12?s Propagation Delay (10mV Overdrive)
MAX982/MAX983 provide a unique, simple method for
adding hysteresis without feedback or complicated
o Output Has Separate GND Pin (MAX9_1/MAX9_4)
equations, simply by using the HYST pin plus two
Applications
resistors.
Battery-Powered
Window Comparators
The MAX971?MAX974 and MAX981?MAX984's open-
Systems
drain outputs permit wire-ORed configurations. Thanks to
Level Translators
an 11V output range and separate GND pin for the output
Threshold Detectors
Oscillator Circuits
transistor (MAX971/MAX974, MAX981/MAX984), these
devices are ideal for level translators and bipolar to single-
Ordering Information
ended converters. For similar devices with complementary
output stages, see the MAX921?MAX924 (1% reference)
PART
TEMP RANGE
PIN-PACKAGE
and the MAX931?MAX934 (2% reference).
0?C to +70?C
MAX971CPA
8 Plastic Dip
0?C to +70?C
MAX971CSA
8 SO
0?C to +70?C
MAX971CUA
8 ?MAX
Ordering Information continued at end of data sheet.
Typical Operating Circuit
VIN
8-Pin
MAX971
1%
1
Yes
DIP/SO/?MAX
7
8-Pin UCSP/
V+
MAX972
None
2
No
DIP/SO/?MAX
3 IN+
8-Pin
OUT 8
MAX973
1%
2
Yes
DIP/SO/?MAX
4 IN-
MAX974
1%
4
No
16-Pin DIP/SO
5 HYST
8-Pin
MAX981
2%
Yes
1
DIP/SO/?MAX
MAX971
6 REF
8-Pin
MAX981
MAX982
2%
Yes
2
DIP/SO/?MAX
GND
V-
2
1
8-Pin
2
MAX983
2%
Yes
DIP/SO/?MAX
THRESHOLD DETECTOR
4
MAX984
2%
No
16-Pin DIP/SO
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.
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
ABSOLUTE MAXIMUM RATINGS
V+ to V-, V+ to GND, GND to V-................................-0.3V, +12V
8-Pin Plastic DIP (derate 9.09mW/?C above +70?C) ...727mW
Inputs
8-Pin SO (derate 5.88mW/?C above +70?C)................471mW
Current: IN_+, IN_-, HYST..............................................20mA
8-Pin ?MAX (derate 4.1mW/?C above +70?C) .............330mW
Voltage: IN_+, IN_-, HYST ...............(V+ + 0.3V) to (V- - 0.3V)
16-Pin Plastic DIP (derate 10.53mW/?C above +70?C)..842mW
Outputs
16-Pin SO (derate 8.70mW/?C above +70?C) ................696mW
Current: REF...................................................................20mA
Operating Temperature Ranges
OUT_ ................................................................50mA
MAX97_C_ _/MAX98_C_ _ ..................................0?C to +70?C
Voltage: REF ....................................(V+ + 0.3V) to (V- - 0.3V)
MAX97_E_ _/MAX98_E_ _ ...............................-40?C to +85?C
OUT_ (MAX9_1/9_4)..................12V to (GND - 0.3V)
Storage Temperature Range .............................-65?C to +150?C
(MAX9_2/9_3).......................12V to (V- - 0.3V)
Lead Temperature (soldering, 10s) .................................+300?C
OUT_ Short-Circuit Duration ..................................Continuous
Bump Temperature (soldering)
Continuous Power Dissipation (TA = +70?C)
Reflow ..........................................................................+235?C
8-Bump UCSP (derate 4.7mW/?C above +70?C) ........379mW
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)
2.5
11
V
Output Voltage Range
0
11
V
TA = +25?C
2.5
3.2
MAX9_1,
HYST = REF
C/E temp ranges
4
TA = +25?C
2.5
3.2
MAX972
C/E temp ranges
4
IN+ = IN- +
Supply Current
100mV
?A
MAX982/
TA = +25?C
3.1
4.5
MAX9_3,
C/E temp ranges
6
HYST = REF
TA = +25?C
5.5
6.5
MAX9_4
C/E temp ranges
8.5
COMPARATOR
Input Offset Voltage
VCM = 2.5V
?10
mV
Input Leakage Current (IN-, IN+)
IN+ = IN- = 2.5V
C/E temp ranges
?0.01
?5
nA
Input Leakage Current (HYST)
MAX9_1/MAX982/MAX9_3
?0.02
nA
Input Common-Mode Voltage
V-
V+ - 1.3
V
Range
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
20
?VRMS
Hysteresis Input Voltage Range
MAX9_1/MAX982/MAX9_3
REF - 0.05
REF
V
Overdrive = 10mV
12
Response Time (High-to-Low
TA = +25?C, 100pF load,
?s
1Mpullup to V+
Transition)
Overdrive = 100mV
4
Response Time (Low-to-High
TA = +25?C, 100pF load, 1Mpullup to V+
300
?s
Transition) (Note 3)
2
_______________________________________________________________________________________
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
ELECTRICAL CHARACTERISTICS--5V OPERATION (continued)
(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
MAX9_2/MAX9_3, IOUT = 1.8mA
V- + 0.4
V
Output Low Voltage
GND
MAX9_1/MAX9_4, IOUT = 1.8mA
+ 0.4
Output Leakage Current
VOUT = 11V
100
nA
REFERENCE (MAX9_1/MAX982/MAX9_3/MAX9_4 ONLY)
C temp range
1%
1.170
1.182
1.194
MAX971/MAX973/
MAX974
E temp range
2%
1.158
1.206
Reference Voltage
V
C temp range
2%
1.158
1.182
1.206
MAX981?MAX984
E temp range
3%
1.147
1.217
TA = +25?C
15
25
Source Current
?A
C/E temp ranges
6
TA = +25?C
8
15
Sink Current
?A
C/E temp ranges
4
Voltage Noise
100Hz to 100kHz
100
?VRMS
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
UNITS
POWER REQUIREMENTS
TA = +25?C
2.4
3.0
MAX9_1
C/E temp ranges
3.8
TA = +25?C
2.4
3.0
MAX972
HYST = REF,
C/E temp ranges
3.8
Supply Current
IN+ = (IN- +
?A
TA = +25?C
3.4
4.3
MAX982/
100mV)
MAX9_3
C/E temp ranges
5.8
TA = +25?C
5.2
6.2
MAX9_4
C/E temp ranges
8.0
COMPARATOR
Input Offset Voltage
VCM = 1.5V
?10
mV
Input Leakage Current (IN-, IN+)
IN+ = IN- = 1.5V
C/E temp ranges
?0.01
?5
nA
Input Leakage Current (HYST)
MAX9_1/MAX982/MAX9_3
?0.02
nA
Input Common-Mode Voltage
V-
V+ - 1.3
V
Range
Common-Mode Rejection Ratio
V- to (V+ - 1.3V)
0.2
1
mV/V
Power-Supply Rejection Ratio
V+ = 2.5V to 11V
0.1
1
mV/V
Voltage Noise
100Hz to 100kHz
20
?VRMS
Hysteresis Input Voltage Range
MAX9_1/MAX982/MAX9_3
REF - 0.05
REF
V
_______________________________________________________________________________________
3
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
TYP
MAX
UNITS
Overdrive = 10mV
12
Response Time (High-to-Low
TA = +25?C, 100pF load,
?s
1Mpullup to V+
Transition)
Overdrive = 100mV
4
Response Time (Low-to-High
TA = +25?C, 100pF load, 1Mpullup to V+
300
?s
Transition) (Note 3)
MAX9_2/MAX9_3, IOUT = 0.8mA
V- + 0.4
V
Output Low Voltage
MAX9_1/MAX9_4, IOUT = 0.8mA
GND + 0.4
Output Leakage Current
VOUT = 11V
100
nA
REFERENCE
C temp range
1%
1.170
1.182
1.194
MAX971/MAX973/
MAX974
E temp range
2%
1.158
1.206
Reference Voltage
V
C temp range
2%
1.158
1.182
1.206
MAX981?MAX984
E temp range
3%
1.147
1.217
TA = +25?C
15
25
Source Current
?A
C/E temp ranges
6
TA = +25?C
8
15
Sink Current
?A
C/E temp ranges
4
Voltage Noise
100Hz to 100kHz
100
?VRMS
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 1Mpullup 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
__________________________________________Typical Operating Characteristics
(V+ = 5V, V- = GND = 0V, TA = +25?C, unless otherwise noted.)
REFERENCE OUTPUT VOLTAGE vs.
OUTPUT VOLTAGE LOW
MAX971/MAX973/MAX974
OUTPUT LOAD CURRENT
vs. LOAD CURRENT
REFERENCE VOLTAGE vs. TEMPERATURE
1.190
2.5
1.22
V+ = 5V
SINK
1.21
1.185
2.0
EXTENDED TEMP RANGE
1.20
1.180
SOURCE
V+ = 3V
COMMERCIAL
1.19
1.5
TEMP RANGE
1.175
1.18
1.170
1.0
1.17
1.165
1.16
V+ = 5V
0.5
OR
1.160
1.15
V+ = 3V
1.155
1.14
0
10
20
30
0
5
15
25
4
8
16
12
0
20
-60 -40 -20 0
20 40 60 80 100 120 140
OUTPUT LOAD CURRENT (?A)
TEMPERATURE (?C)
LOAD CURRENT (mA)
MAX9_1
MAX972
MAX982/MAX9_3
SUPPLY CURRENT vs.
SUPPLY CURRENT vs. TEMPERATURE
SUPPLY CURRENT vs. TEMPERATURE
TEMPERATURE
4.5
4.5
5.0
IN+ = (IN- + 100mV)
IN+ = IN- + 100mV
4.0
4.5
4.0
3.5
4.0
V+ = 5V, V- = - 5V
3.5
V+ = 5V, V- = 0V
V+ = 10V, V- = 0V
3.0
3.5
3.0
2.5
3.0
V+ = 3V, V- = 0V
V+ = 5V, V- = 0V
2.5
2.0
2.5
V+ = 3V, V- = 0V
V+ = 3V, V- = 0V
V+ = 5V, V- = 0V
1.5
2.0
2.0
-20
20
100
-60
140
60
-20
20
100
60
-60
140
-20
20
100
-60
140
60
TEMPERATURE (?C)
TEMPERATURE (?C)
TEMPERATURE (?C)
MAX9_4
MAX9_1/MAX982/MAX9_3
MAX9_4
SUPPLY CURRENT vs.
HYSTERESIS CONTROL
SUPPLY CURRENT vs. TEMPERATURE
LOW SUPPLY VOLTAGES
10
80
10
IN+ = (IN- + 100mV)
60
9
OUTPUT HIGH
40
8
1
20
7
V+ = 5V, V- = -5V
0
NO CHANGE
6
-20
0.1
V+ = 5V, V- = 0V
5
-40
OUTPUT LOW
4
V+ = 3V, V- = 0V
-60
3
-80
0.01
-60
140
-20
20
100
60
0
10
30
50
20
40
1.0
2.0
2.5
1.5
TEMPERATURE (?C)
VREF - VHYST (mV)
SINGLE-SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
5
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
Typical Operating Characteristics (continued)
(V+ = 5V, V- = GND = 0V, TA = +25?C, unless otherwise noted.)
MAX9_1/MAX972/MAX9_4
RESPONSE TIME vs.
RESPONSE TIME FOR VARIOUS
TRANSFER FUNCTION
INPUT OVERDRIVES (VOHL)
LOAD CAPACITANCE
5.0
18
+5V
V- = 0V
10k
4.5
5
16
100k
V0
4.0
4
14
10?F
10mV
3.5
VOHL
3
100mV
12
3.0
2
20mV
2.5
10
1
50mV
2.0
0
8
1.5
100
6
1.0
0
4
0.5
0
2
0.2
-0.3
-0.2  -0.1
0.3
0.1
0
0
20
60
100
40
80
-2
2
6
10
14
18
RESPONSE TIME (?s)
IN+ INPUT VOLTAGE (mV)
LOAD CAPACITANCE (nF)
MAX9_4
RESPONSE TIME
SHORT-CIRCUIT SINK CURRENT
SINK CURRENT
AT LOW SUPPLY VOLTAGES (VOHL)
vs. SUPPLY VOLTAGE
AT LOW SUPPLY VOLTAGES
1000
100
25
RPULLUP = 10k
OUT CONNECTED TO V+
GND CONNECTED TO V-
20
100
10
15
10
-20mV
10
1
5
-100mV
SINK CURRENT AT VOUT = 0.4V
1
0.1
0
1.0
2.0
2.2
2.4
1.2
1.4
1.6
1.8
1.0
2.0
2.5
1.5
5
0
10
SINGLE-SUPPLY VOLTAGE (V)
SINGLE-SUPPLY VOLTAGE (V)
TOTAL SUPPLY VOLTAGE (V)
6
_______________________________________________________________________________________
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
Pin Description
PIN
MAX971/
MAX973/
MAX972
MAX982
MAX981
MAX983
NAME
FUNCTION
DIP/SO/
DIP/SO/
DIP/SO/
DIP/SO/
UCSP
?MAX
?MAX
?MAX
?MAX
Ground. Connect to V- for single-supply operation.
1
--
--
--
--
GND
Negative Supply. Connect to GND for single-supply
2
2
C2
2
2
V-
operation (MAX9_1).
3
--
--
--
--
IN+
Noninverting Comparator Input
4
--
--
--
--
IN-
Inverting Comparator Input
Hysteresis Input. Connect to REF if not used. Input
5
--
--
5
5
HYST
voltage range is from VREF to (VREF - 50mV).
6
--
--
6
6
REF
Reference Output. 1.182V with respect to V-.
7
7
A2
7
7
V+
Positive Supply
8
--
--
--
--
OUT
Comparator Output. Sinks current to GND.
--
1
A1
1
1
OUTA
Comparator A Open-Drain Output. Sinks current to V-.
--
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-.
_______________________________________________________________________________________
7
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
Pin Description (continued)
PIN
NAME
FUNCTION
MAX974
MAX984
1
OUTB
Comparator B Open-Drain Output. Sinks current to GND.
2
OUTA
Comparator A Open-Drain Output. Sinks current to GND.
3
V+
Positive Supply
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-
Negative Supply. Connect to ground for single-supply operation.
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.
8
_______________________________________________________________________________________
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
Detailed Description
Power-Supply and Input Signal Ranges
This family of devices operates from a single 2.5V to 11V
The MAX971?MAX974/MAX981?MAX984 comprise
power supply. The MAX9_1 and MAX9_4 have a
various combinations of a micropower 1.182V reference
separate ground for the output driver, allowing operation
and micropower comparators. The Typical Operating
with dual supplies ranging from ?1.25V to ?5.5V.
Circuit shows the MAX971/MAX981 configuration, and
Connect V- to GND when operating the MAX9_1 or
Figures 1a?1d show the MAX9_2?MAX9_4 configurations.
MAX9_4 from a single supply. The maximum total supply
Internal hysteresis in the MAX9_1, MAX982, and
voltage in this case is still 11V.
MAX9_3 provides the easiest method for implementing
For proper comparator operation, the input signal can
hysteresis. It also produces faster hysteresis action and
range from the negative supply (V-) to within one volt of
consumes much less current than circuits using external
the positive supply (V+ - 1V). The guaranteed common-
positive feedback.
mode 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
OUTB 8
MAX972
OUTB 8 (A3)
1 (A1) OUTA
2 V-
V+ 7
2 (C2) V-
V+ 7 (A2)
3 INA+
REF 6
3 (C1) INA+
INB+ 6 (C3)
HYST 5
4 INB-
INB- 5 (B3)
4 (B1) INA-
V-
Figure 1c. MAX973/MAX983 Functional Diagram
( ) BUMPS FOR THE UCSP
(Window Comparator)
Figure 1a. MAX972 Functional Diagram
MAX9_4
OUTC 16
1 OUTB
OUTD 15
2 OUTA
3 V+
GND 14
IND+ 13
4 INA-
MAX982
1 OUTA
OUTB 8
5 INA+
IND- 12
2 V-
V+ 7
3 INA+
REF 6
6 INB-
INC+ 11
4 INB+
HYST 5
INC- 10
7 INB+
V-
V- 9
8 REF
Figure 1d. MAX974/MAX984 Functional Diagram
Figure 1b. MAX982 Functional Diagram
_______________________________________________________________________________________
9
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
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
THRESHOLDS
IN+
voltages (see Typical Operating Characteristics section).
The MAX9_2 and MAX9_3 have no GND pin, and their
outputs sink current to V-.
HYSTERESIS
IN-
BAND
VREF - VHYST
VHB
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
OUT
capable of sourcing 25?A and sinking 15?A. Do not
bypass the REF output.
Noise Considerations
Although the comparators have a very high gain, useful
Figure 2. Threshold Hysteresis Band
gain is limited by noise. This is shown in the Transfer
Low-Voltage Operation: V+ = 1V
Function graph (see Typical Operating Characteristics).
(MAX9_4 Only)
As the input voltage approaches the comparator's
offset, the output begins to bounce back and forth; this
The guaranteed minimum operating voltage is 2.5V (or
peaks when VIN = VOS. (The lowpass filter shown on the
?1.25V). As the total supply voltage falls below 2.5V,
graph averages out the bouncing, making the transfer
performance degrades and the supply current falls. The
function easy to observe.) Consequently, the
reference will not function below about 2.2V, although
comparator has an effective wideband peak-to-peak
the comparators will continue to operate with a total
noise of around 300?V. The voltage reference has
supply voltage as low as 1V. While the MAX9_4 has
peak-to-peak noise approaching 1mV. Thus, when a
comparators that may be used at supply voltages below
comparator is used with the reference, the combined
2V, the MAX9_1/MAX9_2/MAX9_3 may not be used with
peak-to-peak noise is about 1mV. This, of course, is
supply voltages below 2.5V.
much higher than the RMS noise of the individual
At low supply voltages, the comparators' output sink
components. Take care in your layout to avoid
capability is reduced and the propagation delay
capacitive coupling from any output to the reference
increases (see Typical Operating Characteristics). The
pin. Crosstalk can significantly increase the actual
useful input voltage range extends from the negative
noise of the reference.
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
2.5V TO 11V
range if you anticipate operation below 2.5V.
7
IREF
6
V+
Comparator Output
REF
With 100mV of overdrive, propagation delay is typically
MAX9_1
3?s. The Typical Operating Characteristics show the
R1
MAX982
propagation delay for various overdrive levels. The
MAX9_3
open-drain outputs are intended for wire-ORed and
5
HYST
level-shifting applications. The maximum output voltage
is 11V above V-, and may be applied even when no
R2
V-
supply voltage is present (V+ = V-).
2
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.
Figure 3. Programming the HYST Pin
10
______________________________________________________________________________________
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
__________Applications Information
V+
Hysteresis
RH
Hysteresis increases the comparators' noise margin by
increasing the upper threshold and decreasing the
lower threshold (Figure 2).
RPULLUP
VIN
Hysteresis (MAX9_1/MAX982/MAX9_3)
V+
OUT
To add hysteresis to the MAX9_1, MAX982, or MAX9_3,
MAX9_4 V-
connect resistor R1 between REF and HYST, and
GND
connect resistor R2 between HYST and V- (Figure 3). If
no hysteresis is required, connect HYST to REF. When
VREF
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
Figure 4. External Hysteresis
and to a minimum voltage of (REF - 50mV). The
maximum difference between REF and HYST (50mV)
Board Layout and Bypassing
will therefore produce a 100mV (max) hysteresis band.
Power-supply bypass capacitors are not needed if the
Use the following equations to determine R1 and R2:
supply impedance is low, but 100nF bypass capacitors
VHB
should be used when the supply impedance is high or
R1 =
(
)
2 ?IREF
when the supply leads are long. Minimize signal lead
lengths to reduce stray capacitance between the input
VHB
and output that might cause instability. Do not bypass
1.182 ?
2 
the reference output.
R2 =
IREF
Window Detector
The MAX9_3 is ideal for making window detectors
where IREF (the current sourced by the reference)
(undervoltage/overvoltage detectors). The schematic is
should not exceed the REF source capability, and
shown in Figure 5, with component values selected for a
should be significantly larger than the HYST input
4.5V undervoltage threshold and a 5.5V overvoltage
current. IREF values between 0.1?A and 4?A are usually
appropriate. If 2.4Mis chosen for R2 (IREF = 0.5?A),
threshold. Choose different thresholds by changing the
values of R1, R2, and R3. To prevent chatter at the
the equation for R1 and VHB can be approximated as:
output when the supply voltage is close to a threshold,
R1 (k) = VHB (mV)
hysteresis has been added using R4 and R5. Taken
When hysteresis is obtained in this manner for the
alone, OUTA would provide an active-low undervoltage
MAX982/MAX9_3, the same hysteresis applies to both
indication, and OUTB would give an active-low
comparators.
overvoltage indication. Wired-ORing the two outputs
provides an active-high, power-good signal.
Hysteresis (MAX972/MAX9_4)
The design procedure is as follows:
Hysteresis can be implemented with any comparator
using positive feedback, as shown in Figure 4. This
1) Choose the required hysteresis level and calculate
approach generally draws more current than circuits
values for R4 and R5 according to the formulas in
using the HYST pin on the MAX9_1/MAX982/MAX9_3,
the Hysteresis (MAX9_1/MAX982/MAX9_3) section.
and the high feedback impedance slows hysteresis. In
In this example, ?5mV of hysteresis has been added
addition, because the output does not source current,
at the comparator input (VH = VHB/2). This means
any increase in the upper threshold is dependent on
that the hysteresis apparent at VIN will be larger
the load or pullup resistor on the output.
because of the input resistor divider.
______________________________________________________________________________________
11
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 10Mcan be used, but values in the
VOTH = 5.5V
VIN
5V
100kto 1Mrange are usually easier to deal with.
VUTH = 4.5V
In this example, choose R1 = 294k.
R3
7
1M
1M
V+
3) Calculate R2 + R3. The overvoltage threshold
3 INA+
should be 5.5V when VIN is rising. The design
OUTA 1
equation is as follows:
 VOTH
R2 + R3 = R1 ?
- 1
5 HYST
VREF + VH
R2
R5
62.2k
10k
5.5
= 294kΩ ?
- 1
6 REF
(1.182 + 0.005)
R4
2.4M
= 1.068M
OUTB 8
4 INB-
POWER GOOD
4) Calculate R2. The undervoltage threshold should be
4.5V when VIN is falling. The design equation is as
R1
MAX9_3
V-
294k
follows:
2
(VREF - VH)
R2 = (R1 + R2 + R3) ?/font>
- R1
VUTH
(1.182 - 0.005)
= (294k+ 1.068M) ?/font>
4.5
Figure 5. Window Detector
- 294k
= 62.2k
Battery Switchover Circuit
Choose R2 = 61.9k(1% s tandard value).
The switchover from line-powered DC to a backup
5) Calculate R3:
battery is often accomplished with diodes. But this
simple method is sometimes unacceptable, due to the
R3 = (R2 + R3) - R2
voltage drop and associated power loss across the
diode in series with the battery. Figure 6's circuit
= 1.068MΩ - 61.9k
replaces the diode with a P-channel MOSFET
= 1.006M
controlled by one of the MAX9_3 comparator outputs.
Choose R3 = 1M(1% standard value)
When the DC wall adapter drops below 4V (determined
by R1 and R2), OUTA goes low, turning on Q1.
6) Verify the resistor values. The equations are as
Comparator B is used to measure the battery voltage,
follows, evaluated for the above example:
and gives a "low-battery" indication when the battery
Overvoltage Threshold :
drops below 3.6V.
(R1 + R2 + R3)
VOTH = (VREF + VH ) ?/font>
Level-Shifter
R1
Figure 7 shows a circuit to shift from bipolar ?5V inputs
= 5.474V
to single-ended 5V outputs. The 10kresistors protect
the comparator inputs, and do not materially affect the
Undervoltage Threshold :
circuit's operation.
(R1 + R2 + R3)
VUTH = (VREF - VH ) ?/font>
(R1 + R2)
= 4.484V
R5
where the hysteresis voltage VH = VREF ?/font>
.
R4
12
______________________________________________________________________________________
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
5V
3.3V
3
WALL
V+
ADAPTER
9V DC
MAX974
10k
STEP-DOWN
5 INA+
MAX984
REGULATOR
VINA
3.3V
Q1
LOGIC
OUTA 2
SUPPLY
4
INA-
1M
10k
7
7 INB+
VINB
V+
BATTERY
(4 CELLS)
OUTB 1
MAX973
10k
6 INB-
MAX983
953k
4 INB-
10k
OUTB 8
11 INC+
470k
VINC
LOW BATT
OUTC 16
1 OUTA
10 INC-
R1
DC OK
110k
10k
13 IND+
VIND
3 INA+
OUTD 15
REF 6
20k
12 IND-
8
R2
REF
N.C.
HYST 5
47k
V-
2.4M
V-
GND
2
14
9
-5V
Figure 7. Level Shifter: ?5V Input to Single-Ended 3.3V Output
Figure 6. Battery Switchover Circuit
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
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
Pin Configurations
TOP VIEW
GND
8
8
8
OUTA
OUTA
1
1
1
OUT
OUTB
OUTB
V- 2
V+
7
V+
V+
V- 2
V- 2
7
7
MAX971
MAX972
MAX982
IN+ 3
REF
6
INA+ 3
INA+ 3
6
6
INB+
REF
MAX981
IN- 4
HYST
5
INA- 4
INB+ 4
5
5
INB-
HYST
DIP/SO/?MAX
DIP/SO/?MAX
DIP/SO/?MAX
TOP VIEW
(BUMPS ON BOTTOM)
1
2
3
OUTB 1
16 OUTC
OUTA
8
1
OUTB
A
V+
OUTB
OUTA
OUTA 2
15 OUTD
V- 2
V+
7
MAX973
INA+ 3
REF
6
V+ 3
14 GND
MAX983
B
INA-
MAX972
INB-
INB- 4
HYST
5
MAX974
INA- 4
13 IND+
MAX984
INA+ 5
12 IND-
C
INA+
V-
INB+
DIP/SO/?MAX
INB- 6
11 INC+
INB+ 7
10 INC-
UCSP
REF 8
V-
9
DIP/Narrow SO
14
______________________________________________________________________________________
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
Ordering Information (continued)
PART
TEMP RANGE
PIN-PACKAGE
PART
TEMP RANGE
PIN-PACKAGE
0?C to +70?C
-40?C to +85?C
MAX981CSA
8 SO
MAX971EPA
8 Plastic Dip
0?C to +70?C
-40?C to +85?C
MAX981CUA
8 ?MAX
MAX971ESA
8 SO
-40?C to +85?C
0?C to +70?C
MAX981EPA
8 Plastic Dip
MAX972CPA
8 Plastic Dip
-40?C to +85?C
0?C to +70?C
MAX981ESA
8 SO
MAX972CSA
8 SO
0?C to +70?C
0?C to +70?C
MAX982CPA
8 Plastic Dip
MAX972CUA
8 ?MAX
0?C to +70?C
-40?C to +85?C
MAX982CSA
8 SO
MAX972EBL-T*
8 UCSP-8
0?C to +70?C
-40?C to +85?C
MAX982CUA
8 ?MAX
MAX972EPA
8 Plastic Dip
-40?C to +85?C
-40?C to +85?C
MAX982EPA
8 Plastic Dip
MAX972ESA
8 SO
-40?C to +85?C
0?C to +70?C
MAX982ESA
8 SO
MAX973CPA
8 Plastic Dip
0?C to +70?C
0?C to +70?C
MAX983CPA
8 Plastic Dip
MAX973CSA
8 SO
0?C to +70?C
0?C to +70?C
MAX983CSA
8 SO
MAX973CUA
8 ?MAX
0?C to +70?C
-40?C to +85?C
MAX983CUA
8 ?MAX
MAX973EPA
8 Plastic Dip
-40?C to +85?C
-40?C to +85?C
MAX983EPA
8 Plastic Dip
MAX973ESA
8 SO
-40?C to +85?C
0?C to +70?C
MAX983ESA
8 SO
MAX974CPE
16 Plastic Dip
0?C to +70?C
0?C to +70?C
MAX984CPE
16 Plastic Dip
MAX974CSE
16 Narrow SO
0?C to +70?C
-40?C to +85?C
MAX984CSE
16 Narrow SO
MAX974EPE
16 Plastic Dip
-40?C to +85?C
-40?C to +85?C
MAX984EPE
16 Plastic Dip
MAX974ESE
16 Narrow SO
-40?C to +85?C
0?C to +70?C
MAX984ESE
16 Narrow SO
MAX981CPA
8 Plastic Dip
*UCSP top mark is "ABC."
___________________Chip Information
MAX971/MAX972/MAX973/MAX981/MAX982/MAX984
TRANSISTOR COUNT: 164
MAX974/MAX984 TRANSISTOR COUNT: 267
______________________________________________________________________________________
15
Ultra-Low-Power, Open-Drain,
Single/Dual-Supply Comparators
Package Information
(The package drawing(s) in this data sheet may not reflect the most current