Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - system monitor Reset/power-on reset SOIC 8

1 of 10 041305

FEATURES

§ Holds microprocessor in check during power

transients

§ Automatically restarts microprocessor after

power failure

§ Monitors pushbutton for external override

§ Accurate 5%, 10% or 20% resets for 3.3V

systems and 5% or 10% resets for 5.0V

systems

§ Eliminates the need for discrete components

§ 20% tolerance compatible with 3.0V systems

§ Pin compatible with the MAXIM

MAX707/MAX708 in 8-pin DIP, 8-pin SOIC

packages

§ 8-pin DIP, 8-pin and m-SOP SOIC and 8-pin

m-SOP packages available

§ Industrial temperature range -40°C to +85°C

PIN ASSIGNMENT

See Mech. Drawings Section on website

DS1707 and DS1708_R/S/T

PIN DESCRIPTION

PBRST - Pushbutton Reset Input

- Power Supply

GND - Ground

IN - Input

NMI - Non-maskable Interrupt

NC - No Connect

RST - Active Low Reset Output

RST - Active High Reset Output

DESCRIPTION

The DS1707/DS1708 3.3- or 5.0-Volt MicroMonitor monitors three vital conditions for a microprocessor:

power supply, voltage sense, and external override. A precision temperature-compensated reference and

comparator circuit monitor the status of V

at the device and at an upstream point for maximum

protection. When the sense input detects an out-of-tolerance condition a non-maskable interrupt is

generated. As the voltage at the device degrades an internal power fail signal is generated which forces

the reset to an active state. When V

returns to an in-tolerance condition, the reset signal is kept in the

active state for a minimum of 130 ms to allow the power supply and processor to stabilize.

DS1707/DS1708

3.3 and 5.0-

olt MicroMonito

www.maxim-ic.com

8-Pin DIP (300-mil)

PBRST

GND

RST

NMI

8-Pin

-SOP (118-mil)

RST

PBRST

NMI

GND

8-Pin SOIC (150-mil)

PBRST

GND

RST

NMI

Summary of content (10 pages)

PAGE 1
DS1707/DS1708 3.3 and 5.0-Volt MicroMonitor www.maxim-ic.com FEATURES § § § § § § § § § PIN ASSIGNMENT Holds microprocessor in check during power transients Automatically restarts microprocessor after power failure Monitors pushbutton for external override Accurate 5%, 10% or 20% resets for 3.3V systems and 5% or 10% resets for 5.0V systems Eliminates the need for discrete components 20% tolerance compatible with 3.
PAGE 2
DS1707/DS1708 The third function the DS1707/DS1708 performs is pushbutton reset control. The DS1707/DS1708 debounces the pushbutton input and guarantees an active reset pulse width of 130 ms minimum. OPERATION Power Monitor The DS1707/DS1708 detects out-of-tolerance power supply conditions and warns a processor-based system of impending power failure. When VCC falls below the minimum VCC tolerance, a comparator outputs the RST and RST signals.
PAGE 3
DS1707/DS1708 MICROMONITOR BLOCK DIAGRAM Figure 1 40kW PUSHBUTTON RESET Figure 2 PUSHBUTTON RESET CONTROLLED BY NMI Figure 3 3 of 10
PAGE 4
DS1707/DS1708 TIMING DIAGRAM: PUSHBUTTON RESET Figure 4 NON-MASKABLE INTERRUPT CIRCUIT EXAMPLE Figure 5 VSENSE = R1+ R2 X 1.25 R2 Example: Therefore: VMAX = VSENSE X VCC VTP VSENSE = 4.50V at the trip point VCC = 3.3V 10 kΩ = R2 4.50 X 3.3 = 11.88V maximum 1.25 4.50 = R1 + 10k X 1.
PAGE 5
DS1707/DS1708 TIMING DIAGRAM: NON-MASKABLE INTERRUPT Figure 6 TIMING DIAGRAM: POWER-DOWN Figure 7 5 of 10
PAGE 6
DS1707/DS1708 TIMING DIAGRAM: POWER UP Figure 8 6 of 10
PAGE 7
DS1707/DS1708 ABSOLUTE MAXIMUM RATINGS* Voltage on VCC Pin Relative to Ground Voltage on I/O Relative to Ground** Operating Temperature Storage Temperature Soldering Temperature * -0.5V to +7.0V -0.5V to VCC + 0.5V -40°C to +85°C -55°C to +125°C 260°C for 10 seconds This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied.
PAGE 8
DS1707/DS1708 AC ELECTRICAL CHARACTERISTICS PARAMETER (-40°C to +85°C; VCC=1.2V to 5.5V) SYMBOL MIN PBRST = VIL tPB 150 Reset Active Time tRST 130 VCC Detect to RST and RST tRPD VCC Slew Rate VCC Detect to RST and RST VCC Slew Rate PBRST Stable Low to RST and RST VIN Detect to NMI tF 20 tRPU 130 tR 0 TYP MAX 205 285 ms 5 8 ms 7 ms 205 285 ms 6 ns 5 250 ns 8 ms NOTES: 1. All voltages are referenced to ground. 2.
PAGE 9
DS1707/DS1708 PART MARKING CODES DS170AB yywwrv 8-pin DIP (300 MIL) 8-pin SOIC (150 MIL) 8-pin µSOP (118 MIL) Code AB yww or yyww rv ###xx cccccc cccccc ###xx DS170AB yywwrv ###xx cccccc 170AB ywwrv ###xx Brand Codes Description Values Device type and tolerance 7_, 8_, 8R, 8S, 8T (where’_’ is a blank) Date Code. Identifies the year and y, the last digit of the year. yy, the last two digits of the year. work week the device was ww, the work week (values 01 through 52). assembled.
PAGE 10
DS1707/DS1708 ORDERING INFORMATION ORDERING PACKAGE OPERATING NUMBER TEMPERATURE DS1707EPA 8-pin DIP (300mil) -40°C TO +85°C DS1707ESA 8-pin SOIC (150 mil) -40°C TO +85°C DS1707EUA 8-pin µSOP (118 mil) -40°C TO +85°C DS1708EPA 8-pin DIP (300mil) -40°C TO +85°C DS1708ESA 8-pin SOIC (150 mil) -40°C TO +85°C DS1708EUA 8-pin µSOP (118 mil) -40°C TO +85°C DS1708REPA 8-pin DIP (300mil) -40°C TO +85°C DS1708RESA 8-pin SOIC (150 mil) -40°C TO +85°C DS1708REUA 8-pin µSOP (118 mil) -40°C TO +85°C DS1708SEPA 8-pin DI