Philips PCF1172CT Datasheet

INTEGRATED CIRCUITS

DATA SH EET

PCF1172C

1

3

/2-digit LCD car clock

Product specification
Supersedes data of September 1993
File under Integrated Circuits, IC16

1997 Apr 16

Philips Semiconductors Product specification

31/2-digit LCD car clock

FEATURES

• Driving standard 31⁄2-digit LCD with AM and PM
indicators

• Internal voltage regulator for 5 V LCD

• Option for external stabilized voltage supply

• 4.19 MHz oscillator

• Integrated oscillator output capacitor and polarization

resistor

• Operating ambient temperature: −40 to +85 °C

• 40-lead plastic SMD, face down (VSO40).

ORDERING INFORMATION

TYPE

NUMBER

PCF1172CT VSO40 plastic very small outline package; 40 leads; face down
PCF1172CU − uncased chip in tray

NAME DESCRIPTION VERSION

(2)

GENERAL DESCRIPTION

The PCF1172C is a single chip, 4.19 MHz CMOS clock
circuit indicating hours and minutes. It is designed to drive
a 31⁄2-digit liquid crystal display (LCD) with AM and PM
indicators.

Two external single-pole, single-throw switches will
accomplish all time setting functions. The circuit is
battery-operated via an internal 5 V voltage regulator or by
an external stabilized voltage supply.

PACKAGE

(1)

PCF1172C

SOT158-2

−

Notes

1. See Fig.1 and Chapter “Package outline” for pin layout and package details.

2. See Chapter “Chip dimensions and bonding pad locations” for pad layout and package details.

1997 Apr 16 2

Philips Semiconductors Product specification

31/2-digit LCD car clock

PINNING

SYMBOL PIN DESCRIPTION

OSC OUT 1 oscillator output
OSC IN 2 oscillator input
S1 3 set hour
S3 4 ±2 minute correction
BP 5 64 Hz backplane driver

(common of LCD)
PM 6 segment output for PM annunciator
AM 7 segment output for AM annunciator
E2 8 segment driver
D2 9 segment driver
C2 10 segment driver
E3 11 segment driver
D3 12 segment driver
C3 13 segment driver
E4 14 segment driver
D4 15 segment driver
C4 16 segment driver
B4 17 segment driver
S2 18 set minutes
S4 19 internal voltage regulation
V

SS

S6 21 selectable correction mode
n.c. 22 not connected
V

DD

A4 24 segment driver
F4 25 segment driver
G4 26 segment driver
B3 27 segment driver
A3 28 segment driver
F3 29 segment driver
G3 30 segment driver
P1, P2 31 colon flashing
P3, P4 32 colon static
B2 33 segment driver
A2 34 segment driver
F2 35 segment driver
G2 36 segment driver
B1, C1 37 segment driver

20 negative supply

23 positive supply

PCF1172C

SYMBOL PIN DESCRIPTION

TR 38 test reset; connect to (VDD)
TS 39 test speed-up; connect to (V

) 40 positive supply for test and oscillator

(V

DD

inputs

OSC OUT

OSC IN

1
2
3

S1

4

S3

5

BP

6

PM

7

AM

8

E2

9

D2

10

C2

PCF1172CT

11

E3

12

D3

13

C3

E4

15

D4

16

C4

17

B4

18

S2

19

S4

V

20

SS

MSA986

Fig.1 Pin configuration, PCF1172CT, (VSO40).

(V )

40

DD

39

TS

38

TR

37

B1, C1

36

G2

35

F2

34

A2

33

B2

32

P3, P4

31

P1, P2

30

G3

29

F3

28

A3

2714

B3

26

G4

25

F4

24

A4
V

23

DD

22

n.c.

21

S6

DD

)

1997 Apr 16 3

Philips Semiconductors Product specification

31/2-digit LCD car clock

AM

PM

TIME

A2

B1

F2

G2

C1

E2

D2

Fig.2 Segment designation of LCD.

B2

C2

P1 (P3)

P2 (P4)

AM

F3

E3

A3

G3

D3

B3

C3

F4

E4

PCF1172C

A4

G4

D4

B4

C4

MSA989

Fig.3 Display mode (12-hour with AM/PM annunciator).

OPERATIONAL INPUTS

Operational inputs S1, S2 and S3 have an internal pull-up
resistor to facilitate use of external single-pole,
single-throw switches. A specific debounce circuit is
integrated as protection against contact debounce and
parasitic voltages.

In the description below, an arrangement as shown in
Fig.5 is assumed and S1, S2 and S3 refer to the external
switches rather than the corresponding inputs.

Set hours, switch S1

Closure of S1 increments the hours according to the
correction mode selected by S6 (see Chapter “Input
options”).

MSA990

Set minutes/reset seconds, switch S2

When S2 is closed, the minute setting is corrected
according to the correction mode determined by S6 (see
Chapter “Input options”).

The seconds counter is reset to zero each time S2 is
closed, and begins running each time S2 is opened.

Segment test/reset, switches S1 and S2

If S1 and S2 are closed simultaneously all LCD segments
are switched on. When the switches are released, the
clock starts at 1 : 00.

1997 Apr 16 4

Philips Semiconductors Product specification

31/2-digit LCD car clock

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.

PCF1172C

Single/continuous correction mode, switch S6

For single-set correction mode, S6 is connected to VDD.
Each closure of S1 or S2 advances the counter by one.

For continuous-set correction mode, S6 is connected to
VSS. Momentary closure of S1 or S2 causes single
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
(pin 39) have to be connected to V
frequency (64 Hz) is available at BP (pin 5). The test mode
is activated by connecting TS to VSS (pin 20). All output
frequencies are then increased by a factor of 65536.
In this mode the maximum input frequency is 100 kHz
(external generator at OSC IN). By connecting TR to V
all counters (seconds, minutes and hours) are stopped.
After connecting TR to VDD all counters start from an initial
state.

The switches/inputs described above also operate in the
test mode.

(pin 23). A test

DD

SS

LIMITING VALUES

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

SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT

V

DD

supply voltage with respect to VSS with internal

note 1 − 8V

regulation disconnected

V

I

T

amb

T

stg

all input voltages VSS− 0.3 VDD+ 0.3 V
operating ambient temperature −40 +85 °C
storage temperature −55 +125 °C

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”

.

1997 Apr 16 5