MAX921CSA+ ,Ultra Low-Power, Single/Dual-Supply ComparatorsFeatures®The MAX921–MAX924 single, dual, and quad micro-♦ µMAX Package—Smallest 8-Pin SOpower, low- ..
MAX921CSA+T ,Ultra Low-Power, Single/Dual-Supply ComparatorsELECTRICAL CHARACTERISTICS: 5V OPERATION(V+ = 5V, V- = GND = 0V, T = T to T , unless otherwise note ..
MAX921CSA-T ,Ultra Low-Power, Single/Dual-Supply ComparatorsFeatures®The MAX921–MAX924 single, dual, and quad micro-♦ µMAX Package—Smallest 8-Pin SOpower, low- ..
MAX921CUA ,Ultra Low-Power, Single/Dual-Supply ComparatorsELECTRICAL CHARACTERISTICS: 5V OPERATION (continued)(V+ = 5V, V- = GND = 0V, T = T to T , unless ot ..
MAX921CUA ,Ultra Low-Power, Single/Dual-Supply ComparatorsApplications5 HYSTBattery-Powered SystemsThreshold DetectorsMAX9216 REFWindow ComparatorsGNDV-21Osc ..
MAX921CUA ,Ultra Low-Power, Single/Dual-Supply ComparatorsMAX921–MAX92419-0115; Rev 3; 3/95Ultra Low-Power, Single/Dual-Supply Comparators_______________
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MB8868A ,MOS Universal Asynchronous Receiver / Transmitter (UART)Features
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MB89121 ,8-bit Proprietary MicrocontrollerFUJITSU SEMICONDUCTORDS07-12509-6EDATA SHEET8-bit Proprietary MicrocontrollerCMOS2F MC-8L MB89120/1 ..
MAX921CSA+-MAX921CSA+T-MAX921CSA-T-MAX921CUA+-MAX921ESA+-MAX922CUA+T-MAX922ESA+T-MAX923CSA+-MAX923CUA+-MAX923ESA+-MAX923MSA/PR-MAX924CSE+-MAX924ESE+
Ultra Low-Power, Single/Dual-Supply Comparators
_______________General DescriptionThe MAX921–MAX924 single, dual, and quad micro-
power, low-voltage comparators feature the lowest
power consumption available. These comparators draw
less than 4µA supply current over temperature
(MAX921/MAX922), and include an internal 1.182V
±1% voltage reference, programmable hysteresis, and
TTL/CMOS outputs that sink and source current.
Ideal for 3V or 5V single-supply applications, the
MAX921–MAX924 operate from a single +2.5V to +11V
supply (or a ±1.25V to ±5V dual supply), and each
comparator’s input voltage range swings from the
negative supply rail to within 1.3V of the positive
supply.
The MAX921–MAX924’s unique output stage con-
tinuously sources as much as 40mA. And by eliminating
power-supply glitches that commonly occur when com-
parators change logic states, the MAX921–MAX924
minimize parasitic feedback, which makes them easier to
use.
The single MAX921 and dual MAX923 provide a unique
and simple method for adding hysteresis without
feedback and complicated equations, simply by using
the HYST pin and two resistors.
________________________ApplicationsBattery-Powered Systems
Threshold Detectors
Window Comparators
Oscillator Circuits
____________________________FeaturesµMAX®Package—Smallest 8-Pin SO
(MAX921/MAX922/MAX923)Ultra-Low 4µA Max Quiescent Current
Over Extended Temp. Range (MAX921)Power Supplies:
Single +2.5V to +11V
Dual ±1.25V to ±5.5VInput Voltage Range Includes Negative SupplyInternal 1.182V ±1% Bandgap ReferenceAdjustable Hysteresis TTL/CMOS-Compatible Outputs12µs Propagation Delay (10mV Overdrive)No Switching Crowbar Current40mA Continuous Source Current
Ordering Information continued at end of data sheet.*Dice are tested at TA= +25°C, DCparameters only.
**Contact factory for availability.
MAX921–MAX924
Ultra Low-Power
Single/Dual-Supply ComparatorsMAX921
OUT
IN+
HYST
REFGND
IN-
THRESHOLD DETECTORVIN
__________Typical Operating Circuit19-0115; Rev 6; 4/09
PARTTEMP RANGEPIN-PACKAGE
MAX921CPA0°C to +70°C8 Plastic DIP
MAX921CSA0°C to +70°C8 SO
MAX921C/D0°C to +70°CDice*
PART
INTERNAL 1% PRECISION REFERENCECOMPARATORS PERPACKAGE INTERNALHYSTERESISPACKAGEMAX921Yes1Yes8-Pin
DIP/SO/µMAX
MAX922No2No8-Pin
DIP/SO/µMAX
MAX923Yes2Yes8-Pin
DIP/SO/µMAX
MAX924Yes4No16-Pin
DIP/SO/µMAX
MAX921EPA-40°C to +85°C8 Plastic DIP
MAX921ESA-40°C to +85°C8 SO
MAX921MJA-55°C to +125°C8 CERDIP
MAX921CUA0°C to +70°C8 µMAX
Ordering InformationµMAX is a registered trademark of Maxim Integrated Products, Inc.
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
ABSOLUTE MAXIMUM RATINGSV+ 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
Current, OUT_.................................................................50mA
Voltage, REF....................................(V+ + 0.3V) to (V- – 0.3V)
Voltage, OUT_ (MAX921/924).....(V+ + 0.3V) to (GND – 0.3V)
Voltage OUT_(MAX922/923)...........(V+ + 0.3V) to (V- – 0.3V)
OUT_ Short-Circuit Duration (V+ ≤5.5V)...............Continuous
Continuous Power Dissipation (TA= +70°C)
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
8-Pin CERDIP (derate 8.00mW/°C above +70°C)........640mW
16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)..842mW
16-Pin SO (derate 8.70mW/°C above +70°C)................696mW
16-Pin CERDIP (derate 10.00mW/°C above +70°C)......800mW
Operating Temperature Ranges:
MAX92_C_ _.......................................................0°C to +70°C
MAX92_E_ _.....................................................-40°C to +85°C
MAX92_MJ_ ..................................................-55°C to +125°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
ELECTRICAL CHARACTERISTICS: 5V OPERATION(V+ = 5V, V- = GND = 0V, TA= TMINto TMAX, unless otherwise noted.)
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.
PARAMETERMAX923,
HYST = REF
MIN TYP MAXUNITSMAX924
7.5V-V+ – 1.3
MAX921,
HYST = REF
Supply CurrentIN+ = IN- + 100mV
IN+ = IN- = 2.5V
Supply Voltage Range= +25°C, 100pF load
2.511V
MAX922
Input Offset Voltage
CONDITIONSM temp. range
±10mV= +25°C
C/E temp. ranges
M temp. range
±0.01±5nAInput Leakage Current (IN-, IN+)
(Note 1)
±40
Input Leakage Current (HYST)= +25°C
C/E temp. ranges
M temp. range
±0.02nA
Input Common-Mode Voltage Range= +25°C
VCM= 2.5V
C/E temp. ranges
Common-Mode Rejection Ratio
M temp. range
MAX921, MAX923
0.11.0mV/V
Power-Supply Rejection Ratio
V- to (V+ – 1.3V)
V+ = 2.5V to 11V
100Hz to 100kHz
0.11.0mV/V
Voltage Noise
MAX921, MAX923
Overdrive = 10mV
Overdrive = 100mVµVRMS
Hysteresis Input Voltage RangeREF- 0.05VREFV
C/E temp. ranges
M temp. range= +25°CµsResponse Time
C/E temp. ranges
POWER REQUIREMENTS
COMPARATOR
MAX921–MAX924
Ultra Low-Power
Single/Dual-Supply Comparators
PARAMETERVoltage Noise
C/E temp. ranges: IOUT= 17mA;
M temp. range: IOUT= 10mA
MIN TYP MAXUNITS100Hz to 100kHz100µVRMS
MAX922/
MAX923
C/E temp. ranges: IOUT= 1.8mA;
M temp. range: IOUT= 1.2mA
C/E temp. ranges: IOUT= 1.8mA;
M temp. range: IOUT= 1.2mA
CONDITIONSC temp. rangeOutput High Voltage
E temp. range
MAX92_
M temp. range
V+ – 0.4= +25°C
V- + 0.425C/E temp. ranges6Source Current
M temp. range4= +25°C
GND + 0.4
Output Low Voltage
MAX921/
MAX924
C/E temp. ranges4Sink Current
M temp. range
1.1581.206Reference Voltage
ELECTRICAL CHARACTERISTICS: 5V OPERATION (continued)
(V+ = 5V, V- = GND = 0V, TA= TMINto TMAX, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS: 3V OPERATION(V+ = 3V, V- = GND = 0V, TA= TMINto TMAX, unless otherwise noted.)
PARAMETERMAX923
MIN TYP MAXUNITSMAX924
MAX921
Supply CurrentHYST = REF,
IN+ = (IN- + 100mV)
IN+ = IN- = 1.5V
MAX922
Input Offset Voltage
CONDITIONSM temp. range
±10mV= +25°C
C/E temp. ranges
M temp. range
±0.01±5nAInput Leakage Current (IN-, IN+)±40
Input Leakage Current (HYST)= +25°C
C/E temp. ranges
M temp. range
±0.02nA= +25°C
VCM= 1.5V
C/E temp. ranges
M temp. range
MAX921, MAX923
C/E temp. ranges
M temp. range= +25°C
C/E temp. ranges
REFERENCE(MAX921/MAX923/MAX924 ONLY)
POWER REQUIREMENTS
COMPARATOR
Note 1:MAX924 comparators work below 2.5V, see Low-Voltage Operationsection for more details.
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
Typical Operating Characteristics(V+ = 5V, V- = GND, TA = +25°C, unless otherwise noted).
OUTPUT VOLTAGE LOW
vs. LOAD CURRENT
MAX921/4-TOC1
LOAD CURRENT (mA)
(V)
V+ = 5V
V+ = 3V
OUTPUT VOLTAGE HIGH vs.
LOAD CURRENT
MAX921/924-TOC2
LOAD CURRENT (mA)
(V)40
V+ = 5V
V+ = 3V
REFERENCE OUTPUT VOLTAGE vs.
OUTPUT LOAD CURRENT
MAX921/924-TOC3
OUTPUT LOAD CURRENT (μA)
REFERENCE OUTPUT VOLTAGE (V)20
V+ = 5V
V+ = 3V
SINK
SOURCE
ELECTRICAL CHARACTERISTICS: 3V OPERATION (continued)(V+ = 3V, V- = GND = 0V, TA= TMINto TMAX, unless otherwise noted.)
PARAMETERVoltage Noise
C/E temp. ranges: IOUT= 10mA;
M temp. range: IOUT= 6mA
MIN TYP MAXUNITS100Hz to 100kHz100µVRMS
Input Common-Mode Voltage RangeVV-V+ – 1.3
MAX922/
MAX923= +25°C, 100pF load
C/E temp. ranges: IOUT= 0.8mA;
M temp. range: IOUT= 0.6mA
C/E temp. ranges: IOUT= 0.8mA;
M temp. range: IOUT= 0.6mA
CONDITIONSCommon-Mode Rejection Ratio0.21mV/V
Power-Supply Rejection Ratio
V- to (V+ – 1.3V)
V+ = 2.5V to 11V
100Hz to 100kHz
0.11mV/V
Voltage Noise
MAX921, MAX923
Overdrive = 10mV
Overdrive = 100mVµVRMS
Hysteresis Input Voltage RangeREF- 0.05VREFVµsResponse Time5
C temp. rangeOutput High Voltage
E temp. range
MAX92_
M temp. range
V+ – 0.4= +25°C
V- + 0.425C/E temp. ranges6Source Current
M temp. range4= +25°C
GND + 0.4
Output Low Voltage
MAX921/
MAX924C/E temp. ranges4Sink Current
M temp. range
1.1581.206Reference Voltage
REFERENCE
MAX921-MAX924
Ultra Low-Power
Single/Dual-Supply ComparatorsREFERENCE VOLTAGE
vs. TEMPERATURE
MAX921/924-TOC4
TEMPERATURE (°C)
REFERENCE VOLTAGE (V)100
MILITARY TEMP. RANGE
EXTENDED TEMP. RANGE
COMMERCIAL
TEMP. RANGE
MAX921
SUPPLY CURRENT vs.
TEMPERATURE
MAX921/924-TOC5
TEMPERATURE (°C)
SUPPLY CURRENT (
V+ = 5V, V- = - 5V
V+ = 3V, V- = 0V
V+ = 5V, V- = 0V
IN+ = (IN- + 100mV)
MAX922
SUPPLY CURRENT vs. TEMPERATURE
MAX921/924-TOC6
TEMPERATURE (°C)
SUPPLY CURRENT (
IN+ = (IN- + 100mV)
V+ = 5V, V- = 0V
V+ = 3V, V- = 0V
V+ = 10V, V- = 0V
MAX923
SUPPLY CURRENT vs. TEMPERATURE
MAX921/924-TOC7
TEMPERATURE (°C)
SUPPLY CURRENT (
V+ = 5V, V- = 0V
V+ = 3V, V- = 0V
HYSTERESIS CONTROL
MAX921/924 TOC10
VREF -VHYST (mV)
IN+ – IN- (mV)40
NO CHANGE
OUTPUT LOW
OUTPUT HIGH
MAX924
SUPPLY CURRENT vs. TEMPERATURE
MAX921/924-TOC8
TEMPERATURE (°C)
SUPPLY CURRENT (
IN+ = (IN- + 100mV)
V+ = 5V, V- = 0V
V+ = 3V, V- = 0V
V+ = 5V, V- = -5V
MAX924
SUPPLY CURRENT vs.
LOW SUPPLY VOLTAGES
MAX921/924-TOC9
SINGLE-SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
TRANSFER FUNCTION
4.0MAX921/924-TOC11
IN+ INPUT VOLTAGE (mV)
OUTPUT VOLTAGE (V)
100kV0
10μF2060100
RESPONSE TIME vs.
LOAD CAPACITANCEMAX921/924 TOC12
LOAD CAPACITANCE (nF)
RESPONSE TIME (80
VOLH
V- = 0V
VOHL
Typical Operating Characteristics (continued)(V+ = 5V, V- = GND, TA = +25°C, unless otherwise noted).
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
Typical Operating Characteristics (continued)(V+ = 5V, V- = GND, TA = +25°C, unless otherwise noted).21018
RESPONSE TIME FOR VARIOUS
INPUT OVERDRIVESMAX921/924-TOC13
RESPONSE TIME (μs)
OUTPUT VOLTAGE (V)
10050mV
100mV
20mV
10mV
INPUT VOLTAGE (mV)21018
RESPONSE TIME FOR VARIOUS
INPUT OVERDRIVESMAX921/924-TOC14
RESPONSE TIME (μs)
OUTPUT VOLTAGE (V)
50mV
100mV
20mV
10mV
INPUT VOLTAGE (mV)
MAX924 RESPONSE TIME
AT LOW SUPPLY VOLTAGES
MAX921/924-TOC15
SINGLE-SUPPLY VOLTAGE (V)
RESPONSE TIME (ms)
±20mV OVERDRIVE
±100mV
OVERDRIVE
MAX924 RESPONSE TIME
AT LOW SUPPLY VOLTAGES
MAX921/924-TOC16
SINGLE-SUPPLY VOLTAGE (V)
CURRENT (mA)
SINK CURRENT AT VOUT = 0.4V
SOURCE CURRENT INTO 0.75V LOAD
SHORT-CIRCUIT SOURCE CURRENT
vs. SUPPLY VOLTAGE
160MAX121/124-TOC17
TOTAL SUPPLY VOLTAGE (V)
SOURCE CURRENT (mA)
OUT CONNECTED TO V-
SHORT-CIRCUIT SINK CURRENT
vs. SUPPLY VOLTAGE
MAX121/124-TOC18
TOTAL SUPPLY VOLTAGE (V)
SINK CURRENT (mA)
OUT CONNECTED TO V+
GND CONNECTED TO V-
PIN
MAX921MAX922MAX923NAMEFUNCTION––GNDGround. Connect to V- for single-supply operation. Output swings from V+ to GND.1OUTAComparator A output. Sinks and sources current. Swings from V+ to V-.22V-Negative supply. Connect to ground for single-supply operation (MAX921).––IN+Noninverting comparator input 33INA+Noninverting input of comparator A––IN-Inverting comparator input
____________________________________________________________Pin Descriptions4–INA-Inverting input of comparator A
MAX921–MAX924
Ultra Low-Power
Single/Dual-Supply Comparators
PIN6–
MAX921MAX922MAX923NAMEFUNCTION54INB-Inverting input of comparator B
INB+5HYSTHysteresis input. Connect to REF if not used. Input voltage range is from
VREFto VREF- 50mV.–6REFReference output. 1.182V with respect to V-.
Noninverting input of comparator B77V+Positive supply––OUTComparator output. Sinks and sources current. Swings from V+ to GND. 88OUTBComparator B output. Sinks and sources current. Swings from V+ to V-.
_______________________________________________Pin Descriptions (continued)
PIN
MAX924NAMEFUNCTIONOUTBComparator B output. Sinks and sources current. Swings from V+ to GND. OUTAComparator A output. Sinks and sources current. Swings from V+ to GND. V+Positive supplyINA-Inverting input of comparator AINA+Noninverting input of comparator AINB-Inverting input of comparator BINB+Noninverting input of comparator BREFReference output. 1.182V with respect to V-.V-Negative supply. Connect to ground for single-supply operation.INC-Inverting input of comparator CINC+Noninverting input of comparator CIND-Inverting input of comparator DIND+Noninverting input of comparator DGNDGround. Connect to V- for single-supply operation.OUTDComparator D output. Sinks and sources current. Swings from V+ to GND.OUTCComparator C output. Sinks and sources current. Swings from V+ to GND.
MAX921–MAX924
Ultra Low-Power,
Single/Dual-Supply Comparators
_______________Detailed DescriptionThe MAX921–MAX924 comprise various combinations
of a micropower 1.182V reference and a micropower
comparator. The Typical Operating Circuitshows the
MAX921 configuration, and Figures 1a-1c show the
MAX922–MAX924 configurations.
Each comparator continuously sources up to 40mA,
and the unique output stage eliminates crowbar
glitches during output transitions. This makes them
immune to parasitic feedback (which can cause
instability) and provides excellent performance, even
when circuit-board layout is not optimal.
Internal hysteresis in the MAX921 and MAX923 provides
the easiest method for implementing hysteresis. It also
produces faster hysteresis action and consumes much
less current than circuits using external positive feedback.
Power-Supply and Input Signal RangesThis family of devices operates from a single +2.5V to
+11V power supply. The MAX921 and MAX924 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
MAX921 and the MAX924 from a single supply. The
maximum supply voltage in this case is still 11V.
For proper comparator operation, the input signal can
swing from the negative supply (V-) to within one volt of
the positive supply (V+ – 1V). The guaranteed
common-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.
Operating the MAX921 and MAX924 at ±5V provides
TTL/CMOS compatibility when monitoring bipolar input
signals. TTL compatibility for the MAX922 and MAX923
is achieved by operation from a single +5V supply.
Low-Voltage Operation: V+ = 1V (MAX924 Only)The guaranteed minimum operating voltage is 2.5V (or
±1.25V). As the total supply voltage is reduced below
2.5V, the performance degrades and the supply
current falls. The reference will not function below
OUTA
INA+
INA-
OUTB
INB+
INB-
MAX922
Figure 1a.MAX922 Functional Diagram
OUTA
INA+
INB-
OUTB
REF
HYST
MAX923
Figure 1b.MAX923 Functional Diagram
OUTA
INA-
INA+
OUTD
GND
IND+
IND-
MAX924
OUTB
INB-
INB+
REF
OUTC
INC+
INC-
Figure 1c.MAX924 Functional Diagram
about 2.2V, although the comparators will continue to
operate with a total supply voltage as low as 1V. While
the MAX924 has comparators that may be used at
supply voltages below 2V, the MAX921, MAX922, and
MAX923 may not be used with supply voltages sig-
nificantly below 2.5V.
At low supply voltages, the comparators’ output drive 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 the device
operating from higher supply voltages. Test your
prototype over the full temperature and supply-voltage
range if operation below 2.5V is anticipated.
Comparator OutputWith 100mV of overdrive, propagation delay is typically
3µs. TheTypical Operating Characteristicsshow the
propagation delay for various overdrive levels.
The MAX921 and MAX924 output swings from V+ to
GND, so TTL compatibility is assured by using a +5V
±10% supply. The negative supply does not affect the
output swing, and can range from 0V to -5V ±10%.
The MAX922 and MAX923 have no GND pin, and their
outputs swing from V+ to V-. Connect V- to ground and
V+ to a +5V supply to achieve TTL compatibility.
The MAX921–MAX924’s unique design achieves an
output source current of more than 40mA and a sink
current of over 5mA, while keeping quiescent currents in
the microampere range. The output can source 100mA
(at V+ = 5V) for short pulses, as long as the package's
maximum power dissipation is not exceeded. The
output stage does not generate crowbar switching
currents during transitions, which minimizes feedback
through the supplies and helps ensure stability without
bypassing.
Voltage ReferenceThe 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% in
the range 0°C to +70°C. The REF output is typically
capable of sourcing 15µA and sinking 8µA. Do not
bypass the REF output.
Noise ConsiderationsAlthough the comparators have a very high gain, useful
gain is limited by noise. This is shown in the Transfer
Function graph (seeTypical 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 0.3mV. The voltage reference has
peak-to peak noise approaching 1mV. Thus, when a
MAX921–MAX924
Ultra Low-Power
Single/Dual-Supply ComparatorsTHRESHOLDS
OUT
IN-
IN+
VHB
HYSTERESIS
BANDVREF - VHYST
Figure 2.Threshold Hysteresis Band
HYST
REF
MAX921
MAX923
2.5V TO 11V
IREF
Figure 3.Programming the HYST Pin
