Datasheet

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_______________General Description

The MAX931-MAX934 single, dual, and quad micropower,

low-voltage comparators plus an on-board 2% accurate

reference feature the lowest power consumption available.

These comparators draw less than 4µA supply current

over temperature (MAX931), and include an internal

1.182V ±2% voltage reference, programmable hysteresis,

and TTL/CMOS outputs that sink and source current.

Ideal for 3V or 5V single-supply applications, the

MAX931-MAX934 operate from a single +2.5V to +11V

supply (or a ±1.25V to ±5V dual supply), and each

comparator’s input voltage range extends from the

negative supply rail to within 1.3V of the positive supply.

The MAX931-MAX934’s unique output stage continuously

sources as much as 40mA. And by eliminating power-

supply glitches that commonly occur when comparators

change logic states, the MAX931-MAX934 minimize

parasitic feedback, which makes them easier to use.

The single MAX931 and dual MAX932/MAX933 provide a

unique and simple method for adding hysteresis without

feedback and complicated equations, using the HYST pin

and two resistors.

For applications that require increased precision with

similar power requirements, see the MAX921-MAX924 data

sheet. These devices include a 1% precision reference.

________________________Applications

Battery-Powered Systems

Threshold Detectors

Window Comparators

Oscillator Circuits

Alarm Circuits

____________________________Features

♦ Ultra-Low 4µA Max Quiescent Current

Over Extended Temp. Range (MAX931)

♦ Power Supplies:

Single +2.5V to +11V

Dual ±1.25V to ±5.5V

♦ Input Voltage Range Includes Negative Supply

♦ Internal 1.182V ±2% Bandgap Reference

♦ Adjustable Hysteresis

♦ TTL-/CMOS-Compatible Outputs

♦ 12µs Propagation Delay (10mV Overdrive)

♦ No Switching Crowbar Current

♦ 40mA Continuous Source Current

♦ Available in Space-Saving µMAX Package

MAX931-MAX934

Ultra Low-Power, Low-Cost

Comparators with 2% Reference

________________________________________________________________

Maxim Integrated Products

MAX931

OUT

V-

GND

V+

3

4

5

THRESHOLD DETECTOR

IN+

IN-

HYST

REF

__________Typical Operating Circuit

19-0194; Rev 1; 2/97

8 SO-40°C to +85°CMAX931ESA

8 µMAX0°C to +70°CMAX931CUA

8 SO0°C to +70°CMAX931CSA

8 Plastic DIP0°C to +70°C

MAX931CPA

PIN-PACKAGETEMP. RANGEPART

16-Pin

DIP/SO

No4YesMAX934

8-Pin

DIP/SO/

µMAX

Yes2YesMAX933

8-Pin

DIP/SO/

µMAX

Yes2YesMAX932

8-Pin

DIP/SO/

µMAX

Yes1YesMAX931

PACK-

AGE

INTERNAL

HYSTERESIS

COMPARATORS

PER

PACKAGE

INTERNAL

REFERENCE

PART

Ordering Information continued on last page.

For similar devices guaranteed over the military temp. range, see

the MAX921-MAX924 data sheet. The MAX931, MAX933, and

MAX934 are pin-compatible with the 1% accurate MAX921,

MAX923, and MAX924, respectively. The MAX932 and

MAX922 are not

pin-compatible.

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800

8 Plastic DIP-40°C to +85°CMAX931EPA

______________Ordering Information

Summary of content (16 pages)

PAGE 1
9-0194; Rev 1; 2/97 Ultra Low-Power, Low-Cost Comparators with 2% Reference ____________________________Features ♦ Ultra-Low 4µA Max Quiescent Current Over Extended Temp. Range (MAX931) Ideal for 3V or 5V single-supply applications, the MAX931-MAX934 operate from a single +2.5V to +11V supply (or a ±1.25V to ±5V dual supply), and each comparator’s input voltage range extends from the negative supply rail to within 1.3V of the positive supply. ♦ Internal 1.
PAGE 2
MAX931-MAX934 Ultra Low-Power, Low-Cost Comparators with 2% Reference 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 Current, OUT_ .................................................................
PAGE 3
Ultra Low-Power, Low-Cost Comparators with 2% Reference MAX931-MAX934 ELECTRICAL CHARACTERISTICS—5V Operation (continued) (V+ = 5V, V- = GND = 0V, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER CONDITIONS Output High Voltage C/E temp. ranges, IOUT = 17mA Output Low Voltage C/E temp. ranges, IOUT = 1.8mA MIN TYP MAX V+ – 0.4 UNITS V MAX932, MAX933 V- + 0.4 MAX931, MAX934 GND + 0.4 V REFERENCE X C temp. range 1.158 E temp. range 1.147 1.182 1.
PAGE 4
MAX931-MAX934 Ultra Low-Power, Low-Cost Comparators with 2% Reference ELECTRICAL CHARACTERISTICS—3V Operation (continued) (V+ = 3V, V- = GND = 0V, TA = TMIN to TMAX, unless otherwise noted.) CONDITIONS PARAMETER MIN Input Common-Mode Voltage Range TYP MAX V- V+ – 1.3 Common-Mode Rejection Ratio V- to (V+ – 1.3V) 0.2 1 Power-Supply Rejection Ratio V+ = 2.5V to 11V 0.
PAGE 5
Ultra Low-Power, Low-Cost Comparators with 2% Reference 4.5 4.0 VOH (V) 1.5 1.0 3.5 3.0 2.5 V+ = 3V 0.5 2.0 0.0 12 16 20 0 10 LOAD CURRENT (mA) 30 40 1.165 V+ = 5V OR V+ = 3V 1.160 0 50 MAX921/924-TOC4 EXTENDED TEMP. RANGE COMMERCIAL TEMP. RANGE 1.18 1.17 1.16 IN+ = IN- + 100mV 4.0 IN+ = IN- +100mV 4.5 3.0 V+ = 3V, V- = 0V 2.5 V+ = 5V, V- = 0V 3.5 3.0 2.5 V+ = 3V, V- = 0V 2.0 2.0 -60 -20 MAX933 SUPPLY CURRENT vs. TEMPERATURE SUPPLY CURRENT (µA) 4.5 4.0 V+ = 5V, V- = 0V 3.5 3.
PAGE 6
____________________________Typical Operating Characteristics (continued) (V+ = 5V, V- = GND, TA = +25°C, unless otherwise noted.) HYSTERESIS CONTROL -20 -40 2.5 2.0 1.5 10 20 30 40 50 RESPONSE TIME FOR VARIOUS INPUT OVERDRIVES 2 50mV 1 10mV 0 0 -2 2 6 10 14 18 RESPONSE TIME (µs) 10mV 100mV 2 20mV 1 50mV 100 1 80 100 1 ±20mV OVERDRIVE 0.1 ±100mV OVERDRIVE 0.01 -2 2 6 10 14 18 1.0 2.0 1.5 RESPONSE TIME (µs) SINGLE-SUPPLY VOLTAGE (V) SHORT-CIRCUIT SOURCE CURRENT vs.
PAGE 7
Ultra Low-Power, Low-Cost Comparators with 2% Reference PIN NAME MAX931 MAX932 MAX933 1 – – GND – 1 1 OUTA 2 2 2 V- FUNCTION Ground. Connect to V- for single-supply operation. Output swings from V+ to GND. Comparator A output. Sinks and sources current. Swings from V+ to V-. Negative supply. Connect to ground for single-supply operation (MAX931).
PAGE 8
MAX931-MAX934 Ultra Low-Power, Low-Cost Comparators with 2% Reference _______________Detailed Description The MAX931-MAX934 comprise various combinations of a micropower 1.182V reference and a micropower comparator. The Typical Operating Circuit shows the MAX931 configuration, and Figures 1a-1c show the MAX932/MAX933/MAX934 configurations. Each comparator continuously sources up to 40mA, and the unique output stage eliminates crowbar glitches during output transitions.
PAGE 9
Ultra Low-Power, Low-Cost Comparators with 2% Reference 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.
PAGE 10
MAX931-MAX934 Ultra Low-Power, Low-Cost Comparators with 2% Reference 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. I REF values between 0.1µA and 4µA are usually appropriate. If 2.
PAGE 11
Ultra Low-Power, Low-Cost Comparators with 2% Reference _______________Typical Applications Auto-Off Power Source Figure 5 shows the schematic for a 40mA power supply that has a timed auto power-off function. The comparator output is the switched power-supply output. With a 10mA load, it typically provides a voltage of (VBATT - 0.12V), but draws only 3.5µA quiescent current. This circuit takes advantage of the four key features of the MAX931: 2.
PAGE 12
MAX931-MAX934 Ultra Low-Power, Low-Cost Comparators with 2% Reference 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. 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    5.5 = 294k ×  − 1  (1.182 + 0.005)  = 1.068MΩ 4. Calculate R2.
PAGE 13
Ultra Low-Power, Low-Cost Comparators with 2% Reference MAX931-MAX934 +5V V+ 10k VINA MAX934 INA+ OUTA VIN 0 FOR VINA < 0V 1 FOR VINB > 0V +5V R3 INA- V+ INA+ 10k VINB INPUT VOLTAGE FAIL REF INB+ R2 OUTB R5 HYST INB- R4 10k VINC INC+ INPUT VOLTAGE LOW INB+ OUTC INCR1 MAX932 V- 10k VIND IND+ OUTD INDREF GND N.C. V- -5V Figure 8. Level Shifter: ±5V Input to CMOS Output Figure 9.
PAGE 14
MAX931-MAX934 Ultra Low-Power, Low-Cost Comparators with 2% Reference _________________Pin Configurations _Ordering Information (continued) PART TOP VIEW GND 1 V- 2 IN+ 3 MAX931 IN- 4 V+ 6 REF 5 HYST MAX933CSA MAX933CUA MAX933EPA MAX933ESA MAX934CPE 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 0°C to +70°C 8 SO 8 µMAX 8 Plastic DIP 8 SO 16 Plastic DIP MAX934CSE MAX934EPE MAX934ESE 0°C to +70°C -40°C to +85°C -40°C to +85°C 16 Narrow SO 16 Plastic DIP 16 Narrow SO OUTB V- 2
PAGE 15
Ultra Low-Power, Low-Cost Comparators with 2% Reference PDIPN.EPS SOICN.
PAGE 16
__________________________________________Package Information (continued) 8LUMAXD.EPS MAX931-MAX934 Ultra Low-Power, Low-Cost Comparators with 2% Reference 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.