1997 Apr 16

5

Philips Semiconductors

Product specification

PCF1172C

Time correction

±2 minutes, switch S3

.This switch operates in two ranges:

• Displayed time ≥ 58 minutes 00 seconds

• Displayed time ≤ 1 minute 59 seconds.

When switch S3 is pressed in these ranges, the minutes

and seconds are reset to zero. For displayed

time

≥ 58 minutes 00 seconds, the hour is also

incremented by one.

INPUT OPTIONS

In the description below S4 and S6 refer to the external

switches shown in Fig.5 rather than to the corresponding

inputs.

In a real application, these inputs will normally be bonded

to the appropriate level to give the required function mode.

Internal/external regulation, switch S4

For internal regulation, S4 is closed, the internal voltage

regulator is active and the voltage supply for the LCD is

regulated to 5 V. For external regulation, S4 is open and

the circuit has to be supplied with an externally regulated

voltage.

Single/continuous correction mode, switch S6

Each closure of S1 or S2 advances the counter by one.

For continuous-set correction mode, S6 is connected to

increments as for single-set correction mode. If S1 or S2 is

kept closed for more than 1s, the counter is automatically

incremented by 1 for each full second that S1 or S2 is kept

closed.

TESTING

In normal operation the test inputs TR (pin 38) and TS

frequency (64 Hz) is available at BP (pin 5). The test mode

frequencies are then increased by a factor of 65536.

In this mode the maximum input frequency is 100 kHz

all counters (seconds, minutes and hours) are stopped.

state.

The switches/inputs described above also operate in the

test mode.

LIMITING VALUES

In accordance with the Absolute Maximum Rating System (IEC 134).

Note

1. Connecting the supply voltage with reverse polarity, will not harm the circuit, provided the current is limited to 10 mA

by the external resistor.

HANDLING

Inputs and outputs are protected against electrostatic discharges in normal handling. However, to be totally safe, it is

advisable to take handling precautions appropriate to handling MOS devices. Advice can be found in

“Data Handbook IC16, General, Handling MOS Devices”.

SYMBOL

PARAMETER

CONDITIONS

MIN.

MAX.

UNIT

regulation disconnected

note 1

−

8V

all input voltages

operating ambient temperature

−40

+85

°C

storage temperature

−55

+125

°C