Philips Semiconductors
Product specification
4-digit LCD car clock
FEATURES
•
Driving standard 3
1
⁄
2
or a 4-digit LCD
•
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
PCF1171CT
PCF1171CU
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
PCF1171C
The PCF1171C is a single chip, 4.19 MHz CMOS car clock
circuit indicating hours and minutes. It is designed to drive
a 3
1
⁄
2
or 4-digit liquid crystal display (LCD).
Two external single-pole, single-throw switches will
accomplish all time setting functions. A bonding option
allows the selection of 12-hour or 24-hour display mode.
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
4-digit LCD car clock
PCF1171C
A1
A2
A3
A4
F1
G1
B1 F2
G2
B2
P1 (P3)
F3
G3
B3 F4
G4
B4
E1
C1 E2
C2
P2 (P4)
E3
C3 E4
C4
D1
D2
D3
D4
MSA984
Fig.2 Segment designation of LCD.
TIME
MSA985
Fig.3 Display mode (24-hour mode shown).
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 in the 12-hour mode or 0 : 00 in the
24-hour mode.
1997 Apr 16
4
Philips Semiconductors
Product specification
4-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, S5 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.
12/24-hour mode, switch S5
PCF1171C
For 12-hour display mode, S5 is connected to V
DD
.
For 24-hour display mode, S5 is connected to V
SS
.
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
−
V
SS
−
0.3
−40
−55
MIN.
8
V
DD
+ 0.3
+85
+125
MAX.
V
V
°C
°C
UNIT
1997 Apr 16
5
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