MIC1232

2

January 2006

MIC1232

Micrel, Inc.

Pin Configuration

1

2

3

4

TD

TOL

GND

8

7

6

5

RST

RST

MIC1232

PBRST

ST

8-Pin PDIP Package

8-Pin SOIC Package

Pin Description

Pin Number

Pin Name

Pin Function

1

/PBRST

Pushbutton Reset Input: This input is debounced and can be driven with ex-

ternal logic signals or by means of a mechanical pushbutton to actively force

a reset. All pulses less than 1ms in duration on the /PBRST pin are ignored,

whereas, any pulse with a duration of 20ms or greater is guaranteed to

cause a reset.

2

TD

Time Delay input: This input selects the timebase used by the watchdog

timer. When TD = 0V, the watchdog timeout period is set to a normal value

of 150ms, when TD = open, the watchdog timeout period is et to a nominal

3

TOL

Tolerance Select Input: Selects whether 5% or 10% of VCC is used as the

reset threshold voltage. When TOL = 0V, the 5% tolerance level is selected

4

GND

IC ground pin, 0V reference

5

RST

dog times out or /PBRST is pulled low for a minimum of 20ms. RST remains

asserted for one reset timeout period after VCC exceeds the reset threshold

or after the watch times out or after /PBRST goes high.

6

/RST

dog times out or /PBRST is pulled low for a minimum of 20ms. /RST remains

or after the watch times out or after /PBRST goes high. Open-drain output

7

/ST

Input to watchdog timer. If /ST does not see a transition from high to low

within the watchdog timeout period, RST and /RST will be asserted.

8

VCC

Primary supply input, +5V