INTEGRATED CIRCUITS
DATA SHEET
PCF1175C
4-digit duplex LCD car clock
Product specification
Supersedes data of September 1993
File under Integrated Circuits, IC16
1997 Apr 16
Philips Semiconductors
Product specification
4-digit duplex LCD car clock
FEATURES
•
Internal voltage regulator is electrically programmable
for various LCD voltages
•
Time calibration is electrically programmable
(no trimming capacitor required)
•
LCD voltage adjusts with temperature for good contrast
•
4.19 MHz oscillator
•
12-hour or 24-hour mode
•
Operating ambient temperature:
−40
to +85
°C
•
28-lead plastic SMD (SO28)
•
1 Hz set mode.
ORDERING INFORMATION
TYPE
NUMBER
PCF1175CT
PCF1175CU
PCF1175CU/10
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
SO28
−
−
uncased chip in tray
(2)
chip-on-film frame carrier (FFC)
(2)
DESCRIPTION
plastic small outline package; 28 leads; body width 7.5 mm
(1)
GENERAL DESCRIPTION
PCF1175C
The PCF1175C is a single chip, 4.19 MHz CMOS car clock
circuit providing hours, minutes and seconds functions.
It is designed to drive a 4-digit duplex liquid crystal display
(LCD).
Two external single-pole, single-throw switches will
accomplish all time setting functions. Time calibration and
voltage regulator are electrically programmable via an
on-chip EEPROM. The circuit is battery-operated via an
internal voltage regulator and an external resistor.
VERSION
SOT136-1
−
−
1997 Apr 16
2
Philips Semiconductors
Product specification
4-digit duplex LCD car clock
PINNING
SYMBOL
S1
DATA
OSC IN
OSC OUT
V
SS
MODE
V
PP
TS
ENABLE
V
DD
FLASH
SEL
S2
B4/C4
G4/D4
F4/E4
B3/C3
G3/AD3
F3/E3
A4/COL
B2/C2
G2/D2
F2/E2
B1/C1
A2/ADEG1
AM/PM
BP2
BP1
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
DESCRIPTION
hour adjustment input
EEPROM data input
oscillator input
oscillator output
negative supply voltage
12/24-hour mode select input
programming voltage input
test speed-up mode input
enable input (for S1 and S2)
positive supply voltage
colon option input
EEPROM select input
minute adjustment input
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
segment driver
backplane 2
backplane 1
S1
DATA
OSC IN
OSC OUT
VSS
MODE
V PP
TS
ENABLE
1
2
3
4
5
6
7
PCF1175C
28 BP1
27 BP2
26 AM/PM
25 A2/ADEG1
24 B1/C1
23 F2/E2
22 G2/D2
PCF1175CT
8
9
21 B2/C2
20 A4/COL
19
18
17
16
15
MSB222
V DD 10
FLASH 11
SEL 12
S2 13
B4/C4 14
F3/E3
G3/AD3
B3/C3
F4/E4
G4/D4
Fig.1 Pin configuration, PCF1175CT, (SO28).
1997 Apr 16
3
Philips Semiconductors
Product specification
4-digit duplex LCD car clock
FUNCTIONAL DESCRIPTION AND TESTING
Outputs
The circuit outputs 1 : 2 multiplexed data (duplex) to the
LCD. Generation of BP1 and BP2 (three-level backplane
signals) and the output signals are shown in Fig.4.
PCF1175C
The average voltages across the segments are:
1. V
ON(RMS)
= 0.79 V
DD
2. V
OFF(RMS)
= 0.35 V
DD
.
A1
A2
A3
A4
AM
PM
B1 F2
G1
G2
B2
P1 (P3)
F3
G3
B3 F4
G4
B4
E1
C1 E2
C2
P2 (P4)
E3
C3 E4
C4
D1
D2
D3
D4
MSA992
Fig.2 Segment designation of LCD.
VDD
BP1
VDD /2
0
VDD
BP2
TIME
VDD /2
0
MSA993
PM
(a)
SEGMENT
1
ON
SEGMENT
2
ON
VDD
0
VDD
a. 12-hour mode.
OFF
ON
0
TIME
ON
MSA994
VDD
OFF
0
VDD
(b)
b. 24-hour mode.
OFF
OFF
0
MSB226
15.625 ms
Fig.3 Typical displays.
Fig.4 Backplane and output signals.
1997 Apr 16
4
Philips Semiconductors
Product specification
4-digit duplex LCD car clock
LCD voltage
(see Fig.5)
The adjustable voltage regulator controls the supply
voltage (see Section “LCD voltage programming”) in
relation to temperature for good contrast, for example
when V
DD
= 4.5 V at +25
°C,
then:
V
DD
= 3 to 4 V at +85
°C.
V
DD
= 5 to 6 V at
−40 °C.
PCF1175C
−8
V SS
(V)
−6
(3)
(2)
−4
(1)
MSA995
−2
0
40
0
40
80
T ( o C)
120
(1) Programmed to 4.0 V at 25
°C
(value within the specified operating range).
(2) Programmed to 4.5 V at 25
°C
(value within the specified operating range).
(3) Programmed to 5.0 V at 25
°C
(value within the specified operating range).
Fig.5 Regulated voltage as a function of temperature (typical).
1997 Apr 16
5
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