TS823/824/825

1-6

2003/12 rev. A

TS823/824/825

Microprocessor Supervisory Circuit with

Watchdog Timer & Manual Reset

7 Voltage Threshold Voltage Option

From 2.19V ~ 4.63V

General Description

The TS823/824/825 family allows the user to customize the CPU monitoring function without any external components.

The user has a large choice of reset voltage thresholds and output driver configurations, all of which are present ant

the factory. Each wafer is trimmed to the customer’s specifications.

These circuits will ignore fast negative going transients on Vdd. The state of the reset output is guaranteed to be

correct down to 1V. After Vdd crosses above a factory present threshold, the TS823/824/825 assert a reset signal.

After a predetermined time (the “reset” interval) the reset is deasserted. If Vdd ever drops below the threshold voltage

a reset is asserted immediately. In addition to a supply monitoring function the TS823/824/825 also monitor transitions

at the watchdog (WDI) input. If a logic transition does not occur at the WDI pin within a certain time interval (the

“watchdog” interval) then a reset is asserted. The reset deasserts after the reset interval, as explained earlier.

The TS823/824/825 can both assert a reset manually by pulling the MR input to ground, and the micro-power

quiescent current make this family a natural for portable battery powered equipment.

The TS823/824/825 is available in a 5-pin SOT-25 package.

Features

Precision monitoring of +3V, +3.3V and +5V

power supply voltage

Tight voltage threshold tolerance +/-1.5%

Fully specified over temperature

210mS min. power-on reset pulse width

3uA(typ) supply current

Guaranteed reset valid to Vdd = +1V

Power supply transient immunity

No external components

Ordering Information

Note: x is the threshold voltage type, option as

A: 4.63V

B: 4.38V

D: 3.08V

E: 2.93V

F: 2.63V

G: 2.32V

H: 2.19V

Part No.

Operating Temp.

Package

TS823CX5 x

TS824CX5 x

TS825CX5 x

- 40 ~ +85

SOT-25

Applications

Computers and Controllers

Embedded Controllers

Intelligent instruments

Critical uP monitoring

Portable / Battery powered equipment

Automotive Systems

Pin Assignment

Function

TS823

TS824

TS825

1

1

1

Ground

2

2

2

Manual Reset

3

-

4

-

3

3

Watchdog Input

4

4

-

Supply Voltage (Vdd)

5

5

5