Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - system monitor Dual voltage detector PDIP 8

_______________General Description

The ICL7665 warns microprocessors (µPs) of overvolt-

age and undervoltage conditions. It draws a typical

operating current of only 3µA. The trip points and hys-

teresis of the two voltage detectors are individually pro-

grammed via external resistors to any voltage greater

than 1.3V. The ICL7665 will operate from any supply

voltage in the 1.6V to 16V range, while monitoring volt-

ages from 1.3V to several hundred volts. The Maxim

ICL7665A is an improved version with a 2%-accurate

SET

threshold and guaranteed performance over

temperature.

The 3µA quiescent current of the ICL7665 makes it

ideal for voltage monitoring in battery-powered sys-

tems. In both battery- and line-powered systems, the

unique combination of a reference, two comparators,

and hysteresis outputs reduces the size and compo-

nent count of many circuits.

________________________Applications

µP Voltage Monitoring

Low-Battery Detection

Power-Fail and Brownout Detection

Battery Backup Switching

Power-Supply Fault Monitoring

Over/Undervoltage Protection

High/Low Temperature, Pressure, Voltage Alarms

____________________________Features

♦ µP Over/Undervoltage Warning

♦ Improved Second Source

♦ Dual Comparator with Precision Internal Reference

♦ 3µA Operating Current

♦ 2% Threshold Accuracy (ICL7665A)

♦ 1.6V to 16V Supply Voltage Range

♦ On-Board Hysteresis Outputs

♦ Externally Programmable Trip Points

♦ Monolithic, Low-Power CMOS Design

______________Ordering Information

Ordering Information continued on last page.

ICL7665

Microprocessor Voltage Monitor with

Dual Over/Undervoltage Detection

________________________________________________________________

Maxim Integrated Products

OUT2

SET2

HYST2

GND

SET1

HYST1

OUT1

ICL7665

DIP/SO

TOP VIEW

ICL7665

V+ (CASE)

HYST2

SET2

OUT2

OUT1

HYST1

SET1

TO-99

GND

V+

_________________Pin Configurations

ICL7665

OUT1

OUT2

SET2

SET1

V+ V

IN2

IN1

V+

GND

OVERVOLTAGE

DETECTION

UNDERVOLTAGE

DETECTION

SIMPLE THRESHOLD DETECTOR

NMI

__________Typical Operating Circuit

19-0001; Rev 2; 8/97

PART TEMP. RANGE PIN-PACKAGE

ICL7665CPA 0°C to +70°C 8 Plastic DIP

ICL7665ACPA 0°C to +70°C 8 Plastic DIP

ICL7665BCPA 0°C to +70°C 8 Plastic DIP

ICL7665CSA 0°C to +70°C 8 SO

ICL7665ACSA 0°C to +70°C 8 SO

ICL7665BCSA 0°C to +70°C 8 SO

ICL7665CJA 0°C to +70°C 8 CERDIP

ICL7665ACJA 0°C to +70°C 8 CERDIP

ICL7665BCJA 0°C to +70°C 8 CERDIP

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

For small orders, phone 408-737-7600 ext. 3468.

Summary of content (12 pages)

PAGE 1
9-0001; Rev 2; 8/97 Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection The ICL7665 warns microprocessors (µPs) of overvoltage and undervoltage conditions. It draws a typical operating current of only 3µA. The trip points and hysteresis of the two voltage detectors are individually programmed via external resistors to any voltage greater than 1.3V. The ICL7665 will operate from any supply voltage in the 1.6V to 16V range, while monitoring voltages from 1.3V to several hundred volts.
PAGE 2
ICL7665 Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection ABSOLUTE MAXIMUM RATINGS Supply Voltage (Note 1) .........................................-0.3V to +18V Output Voltages OUT1 and OUT2 (with respect to GND) (Note 1) ..........................-0.3V to +18V Output Voltages HYST1 and HYST2 (with respect to V+) (Note 1) .............................+0.3V to -18V Input Voltages SET1 and SET2 (Note 1)........................................(GND - 0.3V) to (V+ + 0.
PAGE 3
Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection (V+ = 5V, TA = +25°C, unless otherwise noted.
PAGE 4
ICL7665 Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection AC OPERATING CHARACTERISTICS (V+ = 5V, TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN tSO1d tSH1d Output Delay Time, Input Going High tSO2d VSET switched from 1.0V to 1.6V, ROUT = 4.7kΩ, CL = 12pF, RHYST = 20kΩ 90 tSH1d 55 75 VSET switched from 1.6V to 1.0V, ROUT = 4.7kΩ, CL = 12pF, RHYST = 20kΩ 80 60 tO1r 0.6 tH1r VSET switched between 1.0V and 1.6V, ROUT = 4.7kΩ, CL = 12pF, RHYST = 20kΩ 0.
PAGE 5
Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection SUPPLY CURRENT AS A FUNCTION OF SUPPLY VOLTAGE 0V ≤ VSET1, VSET2 ≤ V+ 4.5 V+ = 9V V+ = 15V 0.5 3.5 TA = -20°C 3.0 TA = +25°C 2.5 TA = +70°C 2.0 1.5 5 15 10 2 4 6 8 10 12 SUPPLY VOLTAGE (V) 14 16 -0.8 V+ = 9V -1.2 V+ = 2V -2.0 ICL7665-05 V+ = 15V V+ = 9V V+ = 5V -3 V+ = 2V -4 -4 HYST1 OUTPUT CURRENT (mA) 0 1.5 V+ = 2V V+ = 5V V+ = 9V V+ = 15V 1.0 0.5 0 -5 -8 60 2.
PAGE 6
ICL7665 Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection V+ 4.7k OUT1 HYST1 INPUT 1.6V V+ 8 OUT2 7 SET1 SET2 6 GND HSYT2 5 1 OUT1 2 HYST1 3 4 ICL7665 1.0V 4.7k OUT2 HSYT2 20k 20k 12pF 12pF 12pF 12pF Figure 1. Test Circuit _______________Detailed Description As shown in the block diagram of Figure 2, the Maxim ICL7665 combines a 1.3V reference with two comparators, two open-drain N-channel outputs, and two open-drain P-channel hysteresis outputs.
PAGE 7
Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection V+ V+ OUT1 OUT2 OUT1 VIN1 VIN2 R22 R21 OUT2 R22 ICL7665 R31 SET2 SET1 SET2 R12 R32 HYST2 HYST1 R11 VIN2 R21 ICL7665 SET1 ICL7665 VIN1 R12 R11 V+ OUT1 OUT1 VL1 VIN1 0V VU1 VIN1 VTRIP1 OUT2 V+ OUT2 VIN2 VTRIP2 0V VIN2 Figure 3. Simple Threshold Detector Basic Over/Undervoltage Detection Circuits Figures 3, 4, and 5 show the three basic voltage detection circuits.
PAGE 8
ICL7665 Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection Figure 5 1) Select a value for R11, usually between 10kΩ and 10MΩ. 2) Calculate R21: VIN R31 R32 HYST1 V+ ( R22 ICL7665 SET1 SET2 OUT1 OUT2 UNDERVOLTAGE OVERVOLTAGE GND R11 R12 OUT1 VL1 VU1 OUT2 VIN ) ) VU – VL R31 = R11 ————— VSET 4) As in the other circuits, all three resistor values may be scaled up or down in value without changing VU and VL.
PAGE 9
Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection Nickel cadmium (NiCd) batteries are excellent rechargeable power sources for portable equipment, but care must be taken to ensure that NiCd batteries are not damaged by overdischarge. Specifically, a NiCd battery should not be discharged to the point where the polarity of the lowest-capacity cell is reversed, and that cell is reverse charged by the higher-capacity cells.
PAGE 10
ICL7665 Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection +5V SUPPLY HYST1 324k 13M 5% V+ R21A 274k 100k SET2 OUT1 +15V UNDERVOLTAGE 100k DETECTOR VU ≈ 4.55V VL ≈ 4.45V OUT2 ICL7665 SET2 R21B 1.02M 100k 22M 249k 7.5M 5% ICL7665 V+ HYST1 R31 22M +5V HYST2 SET1 OVERVOLTAGE DETECTOR VU ≈ 5.55V VL ≈ 5.45V +5V HYST2 SET1 OUT2 R11 49.9k 301k OUT1 787k +5V -5V -15V POWER OK POWER OK Figure 6. Fault Monitor for a Single Supply Figure 7.
PAGE 11
Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection ICL7665 VCC TO CMOS MEMORY Q1 LINE-POWERED +5V INPUT 100k 1µF 1k 2N7000 2N4393 1M OUT1 V+ HYST1 HYST2 5.6M 22M ICL7665 2.4M SET1 3V LITHIUM CELL 1.15M 1% SET2 1M GND 1M 1% OUT2 220Ω Figure 11.
PAGE 12
ICL7665 Microprocessor Voltage Monitor with Dual Over/Undervoltage Detection _______________________SCR Latchup Like all junction-isolated CMOS circuits, the ICL7665 has an inherent four-layer or SCR structure that can be triggered into destructive latchup under certain conditions. Avoid destructive latchup by following these precautions: 1) If either VSET terminal can be driven to a voltage greater than V+ or less than ground, limit the input current to 500µA maximum.