INTEGRATED CIRCUITS
DATA SHEET
PCF1172C
3
1
/
2
-digit LCD car clock
Product specification
Supersedes data of September 1993
File under Integrated Circuits, IC16
1997 Apr 16
Philips Semiconductors
Product specification
3
1
/
2
-digit LCD car clock
FEATURES
•
Driving standard 3
1
⁄
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
PCF1172CU
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.
PACKAGE
NAME
VSO40
−
uncased chip in tray
(2)
DESCRIPTION
plastic very small outline package; 40 leads; face down
(1)
GENERAL DESCRIPTION
PCF1172C
The PCF1172C is a single chip, 4.19 MHz CMOS clock
circuit indicating hours and minutes. It is designed to drive
a 3
1
⁄
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.
VERSION
SOT158-2
−
1997 Apr 16
2
Philips Semiconductors
Product specification
3
1
/
2
-digit LCD car clock
PINNING
SYMBOL
OSC OUT
OSC IN
S1
S3
BP
PM
AM
E2
D2
C2
E3
D3
C3
E4
D4
C4
B4
S2
S4
V
SS
S6
n.c.
V
DD
A4
F4
G4
B3
A3
F3
G3
P1, P2
P3, P4
B2
A2
F2
G2
B1, C1
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
DESCRIPTION
oscillator output
oscillator input
set hour
±2
minute correction
64 Hz backplane driver
(common of LCD)
segment output for PM annunciator
segment output for AM annunciator
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
set minutes
internal voltage regulation
negative supply
selectable correction mode
not connected
positive supply
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
colon flashing
colon static
segment driver
segment driver
segment driver
segment driver
segment driver
C4 16
B4 17
S2 18
S4 19
V SS 20
MSA986
PCF1172C
SYMBOL
TR
TS
(V
DD
)
PIN
38
39
40
DESCRIPTION
test reset; connect to (V
DD
)
test speed-up; connect to (V
DD
)
positive supply for test and oscillator
inputs
OSC OUT
OSC IN
S1
S3
BP
PM
AM
E2
D2
1
2
3
4
5
6
7
8
9
40 (V DD )
39 TS
38 TR
37 B1, C1
36 G2
35 F2
34 A2
33 B2
32 P3, P4
31 P1, P2
C2 10
PCF1172CT
E3
11
30 G3
29 F3
28 A3
27 B3
26 G4
25 F4
24 A4
23
VDD
D3 12
C3 13
E4 14
D4 15
22 n.c.
21 S6
Fig.1 Pin configuration, PCF1172CT, (VSO40).
1997 Apr 16
3
Philips Semiconductors
Product specification
3
1
/
2
-digit LCD car clock
PCF1172C
A2
A3
A4
AM
PM
B1 F2
G2
B2
P1 (P3)
F3
G3
B3 F4
G4
B4
C1 E2
C2
P2 (P4)
E3
C3 E4
C4
D2
D3
D4
MSA989
Fig.2 Segment designation of LCD.
TIME
AM
MSA990
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”).
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
3
1
/
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 V
DD
.
Each closure of S1 or S2 advances the counter by one.
For continuous-set correction mode, S6 is connected to
V
SS
. 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
DD
(pin 23). A test
frequency (64 Hz) is available at BP (pin 5). The test mode
is activated by connecting TS to V
SS
(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
SS
all counters (seconds, minutes and hours) are stopped.
After connecting TR to V
DD
all counters start from an initial
state.
The switches/inputs described above also operate in the
test mode.
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
SYMBOL
V
DD
V
I
T
amb
T
stg
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”.
PARAMETER
supply voltage with respect to V
SS
with internal
regulation disconnected
all input voltages
operating ambient temperature
storage temperature
CONDITIONS
note 1
−
MIN.
8
MAX.
V
UNIT
V
SS
−
0.3 V
DD
+ 0.3 V
−40
−55
+85
+125
°C
°C
1997 Apr 16
5
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