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SP791DS/08

SP791 Low Power Microprocessor Supervisory with Battery Switch-Over

© Copyright 2000 Sipex Corporation

s Precision 4.65V Voltage Monitoring

s 200ms Power-OK/Reset Time Delay

s Independent Watchdog Time-Preset or Adjustable

s 75

µA Maximum Operating Supply Current

s 1.0

µA Maximum Battery Backup Current

s 0.1

µA Maximum Battery Standby Current

s Power Switching

250mA Output in Vcc Mode (0.6

Ω)

25mA Output in Battery Mode (5

Ω)

s On-Board Gating of Chip-Enable Signals

Memory Write-Cycle Completion

6ns CE Gate Propagation Delay

s Voltage Monitor for Power-Fail or Low Battery

s Backup-Battery Monitor

s RESET Valid to Vcc=1V

s Pin Compatible Upgrade to MAX791

DESCRIPTION

The SP791 is a microprocessor (

µP) supervisory circuit that integrates a myriad of compo-

nents involved in discrete solutions to monitor power-supply and battery-control functions in

µP and digital systems. The SP791 offers complete µP monitoring and watchdog functions.

The SP791 is ideal for a low-cost battery management solution and is well suited for portable,

battery-powered applications with its supply current of 40

µA. The 6ns chip-enable propaga-

tion delay, the 25mA current output in battery-backup mode, and the 250mA current output

in standard operation also makes the SP791 suitable for larger scale, high-performance

equipment.

SP791

Figure 1. Block Diagram

150mV

4.65V

Vcc

13

1

3

LOWLINE

BATT ON

10

5

2

CE OUT

12

+

+

+

_

_

_

+

_

_

+

SP791

MR

SWT

WDI

PFI

1.25V

4

GND

7

11

8

9

RESET

WDPO

PFO

16

15

WDO

14

6

+

_

+

_

WATCHDOG

TIMER

TIMEBASE FOR

RESET AND

WATCHDOG

WATCHDOG

TRANSITION

DETECTOR

RESET

GENERATION

2V

CHIP-ENABLE

OUTPUT

CONTROL

Low Power Microprocessor Supervisory

with Battery Switch-Over

®