Date: 5/25/04

SP691A/693A/800L/800M Low Power Microprocessor Supervisor with Battery Switch-Over © Copyright 2004 Sipex Corporation

16

Continuous current should be limited to 25mA

and peak currents (only during power-up)

limited to 250mA. The reverse leakage of this

input is less than 1

µA over temperature and

supply voltage.

Output Supply Voltage

the current to the external system and internal

circuitry. All open-circuit outputs will assume

with 0.1

µF capacitor.

TYPICAL APPLICATIONS

The SP691A/693A/800L/800M devices are not

ground, other than power-up transients such as

charging a decoupling capacitor, may destroy

the device. All open-circuit outputs swing

GND. If long leads connect to the chip inputs,

ensure that these lines are free from ringing and

other conditions that would forward bias the

chip's protection diodes.

There are three distinct modes of operation:

1) Normal operating mode with all circuitry

powered from V

from V

currents flow from the battery.

2) Battery-backup mode where V

within 0.7V below V

powered from V

current from the battery is typically less

than 5

µA.

3) Battery-backup mode where V

V

current is less than 1

µA max.

Using High Capacity Capacitor with the

SP691A/693A/800L/800M Series

allowing use of a capacitor and a simple

charging circuit as a backup source. Refer to

Figure 25.

Leakage current through the capacitor charging

diode and SP691A/693A/800L/800M internal

power diode eventually discharges the capacitor

above the reset threshold and power is lost at

SP691A/693A/800L/800M devices then switch

to battery-backup mode.

Using Separate Power Supplies for V

BATT

and V

CC

Refer to Figure 24.

Alternative Chip-Enable Gating

Using memory devices with CE and CE inputs

allows the CE loop of the SP691A/693A/800L/

800M series to be bypassed. To do this,

connect CE

OUT

,

Figure 25. High Capacity Capacitor on V

BATT

Corporation

+5V

1N4148

0.47F

1

3

2

4

Vcc

GND