Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsLinear IC - Comparator Multi-purpose CMOS, TTL PDIP 8

_______________General Description

The 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.

________________________Applications

Battery-Powered Systems

Threshold Detectors

Window Comparators

Oscillator Circuits

____________________________Features

♦ µMAX

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 ±5.5V

♦ Input Voltage Range Includes Negative Supply

♦ Internal 1.182V ±1% Bandgap Reference

♦ Adjustable Hysteresis

♦ TTL/CMOS-Compatible Outputs

♦ 12µs Propagation Delay (10mV Overdrive)

♦ No Switching Crowbar Current

♦ 40mA Continuous Source Current

Ordering Information continued at end of data sheet.

*Dice are tested at T

= +25°C, DC parameters only.

**Contact factory for availability.

MAX921–MAX924

Ultra Low-Power,

Single/Dual-Supply Comparators

________________________________________________________________ Maxim Integrated Products 1

MAX921

OUT

IN+

HYST

REF

V-

GND

V+

IN-

THRESHOLD DETECTOR

__________Typical Operating Circuit

19-0115; Rev 6; 4/09

PART TEMP RANGE PIN-PACKAGE

MAX921CPA

0°C to +70°C 8 Plastic DIP

MAX921CSA 0°C to +70°C 8 SO

MAX921C/D 0°C to +70°C Dice*

PART

INTERNAL 1%

PRECISION

REFERENCE

COMPARATORS

PER

PACKAGE

INTERNAL

HYSTERESIS

PACKAGE

MAX921 Yes 1 Yes

8-Pin

DIP/SO/µMAX

MAX922 No 2 No

8-Pin

DIP/SO/µMAX

MAX923 Yes 2 Yes

8-Pin

DIP/SO/µMAX

MAX924 Yes 4 No

16-Pin

DIP/SO/µMAX

MAX921EPA -40°C to +85°C 8 Plastic DIP

MAX921ESA -40°C to +85°C 8 SO

MAX921MJA -55°C to +125°C 8 CERDIP

MAX921CUA 0°C to +70°C 8 µMAX

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim's website at www.maxim-ic.com.

Ordering Information

µMAX is a registered trademark of Maxim Integrated Products, Inc.

Summary of content (17 pages)

PAGE 1
9-0115; Rev 6; 4/09 Ultra Low-Power, Single/Dual-Supply Comparators The MAX921–MAX924 single, dual, and quad micropower, 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.
PAGE 2
MAX921–MAX924 Ultra Low-Power, 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 Current, OUT_ .................................................................50mA Voltage, REF ........
PAGE 3
Ultra Low-Power, Single/Dual-Supply Comparators MAX921–MAX924 ELECTRICAL CHARACTERISTICS: 5V OPERATION (continued) (V+ = 5V, V- = GND = 0V, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER Output High Voltage Output Low Voltage CONDITIONS MIN TYP MAX MAX92_ C/E temp. ranges: IOUT = 17mA; M temp. range: IOUT = 10mA MAX922/ MAX923 C/E temp. ranges: IOUT = 1.8mA; M temp. range: IOUT = 1.2mA V- + 0.4 MAX921/ MAX924 C/E temp. ranges: IOUT = 1.8mA; M temp. range: IOUT = 1.2mA GND + 0.4 V+ – 0.
PAGE 4
ELECTRICAL CHARACTERISTICS: 3V OPERATION (continued) (V+ = 3V, V- = GND = 0V, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER CONDITIONS Input Common-Mode Voltage Range Common-Mode Rejection Ratio Power-Supply Rejection Ratio Voltage Noise Hysteresis Input Voltage Range MIN TYP VV- to (V+ – 1.3V) V+ = 2.5V to 11V 100Hz to 100kHz MAX921, MAX923 0.2 0.1 20 MAX UNITS V+ – 1.3 1 1 V mV/V mV/V µVRMS V REF- 0.
PAGE 5
Ultra Low-Power, Single/Dual-Supply Comparators MAX921 SUPPLY CURRENT vs. TEMPERATURE COMMERCIAL TEMP. RANGE 1.19 1.18 1.17 1.16 4.0 V+ = 5V, V- = - 5V 3.5 3.0 V+ = 3V, V- = 0V IN+ = (IN- + 100mV) 4.0 3.5 V+ = 10V, V- = 0V 3.0 2.5 V+ = 5V, V- = 0V 2.5 2.0 1.15 V+ = 3V, V- = 0V V+ = 5V, V- = 0V 2.0 1.14 -60 -40 -20 0 -20 20 60 100 140 -60 -20 20 100 60 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) MAX923 SUPPLY CURRENT vs. TEMPERATURE MAX924 SUPPLY CURRENT vs.
PAGE 6
Typical Operating Characteristics (continued) (V+ = 5V, V- = GND, TA = +25°C, unless otherwise noted). 50mV 1 10mV 0 -2 2 6 10 10mV 100mV 2 20mV 1 50mV 14 18 RESPONSE TIME (μs) 100 0.01 -2 1 2 6 10 14 18 1.0 2.0 1.5 RESPONSE TIME (μs) SINGLE-SUPPLY VOLTAGE (V) SHORT-CIRCUIT SOURCE CURRENT vs. SUPPLY VOLTAGE SHORT-CIRCUIT SINK CURRENT vs. SUPPLY VOLTAGE 200 OUT CONNECTED TO V- 160 140 120 100 80 60 2.
PAGE 7
Ultra Low-Power, Single/Dual-Supply Comparators PIN NAME FUNCTION MAX921 MAX922 MAX923 – 5 4 INB- Inverting input of comparator B 5 – 5 HYST Hysteresis input. Connect to REF if not used. Input voltage range is from VREF to VREF - 50mV. 6 – 6 REF Reference output. 1.182V with respect to V-. – 6 – INB+ Noninverting input of comparator B 7 7 7 V+ 8 – – OUT Comparator output. Sinks and sources current. Swings from V+ to GND. – 8 8 OUTB Comparator B output.
PAGE 8
MAX921–MAX924 Ultra Low-Power, Single/Dual-Supply Comparators _______________Detailed Description The MAX921–MAX924 comprise various combinations of a micropower 1.182V reference and a micropower comparator. The Typical Operating Circuit shows 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.
PAGE 9
Ultra Low-Power, Single/Dual-Supply Comparators INVREF - VHYST HYSTERESIS VHB 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% 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. OUT Figure 2. Threshold Hysteresis Band about 2.
PAGE 10
MAX921–MAX924 Ultra Low-Power, Single/Dual-Supply Comparators 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. Care should be taken in the layout to avoid capacitive coupling from any output to the reference pin. Crosstalk can significantly increase the actual noise of the reference.
PAGE 11
Ultra Low-Power, Single/Dual-Supply Comparators Auto-Off Power Source MOMENTARY SWITCH 4.5V TO 6.0V 7 V+ 6 MAX921 IN+ 3 REF 47k C 5 R HYST 1.1M OUT 8 VBATT -0.15V 10mA 4 IN100k V2 GND 1 Figure 5. Auto-off power switch operates on 2.5µA quiescent current. 6.
PAGE 12
MAX921–MAX924 Ultra Low-Power, 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. 3. Calculate R2 + R3. The overvoltage threshold should be 5.5V when V IN is rising.
PAGE 13
Ultra Low-Power, Single/Dual-Supply Comparators MAX921–MAX924 R2 R1 VIN 1.182V 8 +5V +5V 3 V+ V+ REF MAX924 10k MAX924 INA+ VINA OUTA V- 9 INA- 5 INA+ 182k 0 FOR VINA < 0V 1 FOR VINB > 0V OUTA 2 10k 1V 330Ω 4 INA- INB+ VINB OUTB 250k INB- 7 INB+ OUTB 1 750mV 6 330Ω INB- 10k VINC INC+ OUTC 250k INC- 11 INC+ OUTC 16 330Ω 500mV 10 INC- 10k VIND IND+ OUTD 250k IND- 13 IND+ REF OUTD 15 330Ω 250mV 12 IND- 250k N.C. GND GND 14 Figure 7.
PAGE 14
MAX921–MAX924 Ultra Low-Power, Single/Dual-Supply Comparators _________________Pin Configurations _Ordering Information (continued) PART TOP VIEW TEMP RANGE -55°C to +125°C 8 SO** -55°C to +125°C 8 SO** GND 1 8 OUT MAX921MSA/PR-T V- 2 7 V+ MAX922CPA 0°C to +70°C 8 Plastic DIP 6 REF MAX922CSA 0°C to +70°C 8 SO 5 HYST IN+ 3 MAX921 IN- 4 DIP/SO/μMAX MAX922CUA 0°C to +70°C 8 µMAX MAX922C/D 0°C to +70°C Dice* MAX922EPA -40°C to +85°C 8 Plastic DIP MAX922ESA -40°C to +85°C
PAGE 15
Ultra Low-Power, Single/Dual-Supply Comparators MAX921/MAX922/MAX923 MAX924 OUTB OUTA 10 1 OUTC OUTD V+ 9 2 8 3 GND 0.075" (1.91mm) 4 7 5 0.108" (2.74mm) 6 IND+ INA- IND- INA+ 0.059" (1.50mm) DIE PAD 1 2 3 4 5 6 7 8 9 10 MAX921 GND VVIN+ INHYST REF V+ V+ OUT INC+ INB- MAX922 OUTA VVINA+ INAINBINB+ V+ V+ OUTB MAX923 OUTA VVINA+ INBHYST REF V+ V+ OUTB INB+ REF V- INC- 0.069" (1.
PAGE 16
MAX921–MAX924 Ultra Low-Power, Single/Dual-Supply Comparators Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. 16 PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
PAGE 17
Ultra Low-Power, Single/Dual-Supply Comparators REVISION NUMBER REVISION DATE 4 8/08 5 8/08 Adding information for rugged plastic product 6 4/09 Updated Ordering Information DESCRIPTION Updated TOCs 5 and 10 PAGES CHANGED 5 1, 14 1, 14, 16 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.