CA3162E Intersil, CA3162E Datasheet - Page 5

• Manufacturer Part Number: CA3162E
• Description: IC CONVERTER A/D 3-DIGIT 16-DIP
• Manufacturer: Intersil

Specifications of CA3162E

• Rohs Status: RoHS non-compliant
• Other names: CA3162

CA3162E Liquid Crystal Display (LCD) Application
Figure 3 shows the CA3162E in a typical LCD application.
LCDs may be used in favor of LED displays in applications
requiring lower power dissipation, such as battery-operated
equipment, or when visibility in high-ambient-light conditions
is desired.
Multiplexing of LCD digits is not practical, since LCDs must
be driven by an AC signal and the average voltage across
each segment is zero. Three CD4056B liquid-crystal
decoder/drivers are therefore used. Each CD4056B contains
an input latch so that the BCD data for each digit may be
latched into the decoder using the inverted digit-select out-
puts of the CA3162E as strobes.
The capacitors on the outputs of inverters G3 and G4 filter
out the decode spikes on the MSD and NSD signals. The
“HOLD”
50kΩ
V
V
IN
IN
ZERO
+
-
G7, G8, G9: CD4023B
GAIN
G1 - G6: CD4049UB
10kΩ
8
9
11
10 13
CA3162E
+5V
14
HEX INVERTER
TRIPLE 3 INPUT NAND GATE
12
16
15
0.27µF
4
3
5
1
2
7
100kΩ
MSD
NSD
LSD
2
2
2
2
3
2
1
0
4 x
10kΩ
+5V
6 x
FIGURE 3. TYPICAL LCD APPLICATION
0.047µF
0.047µF
0.047
µF
G8
G7
CA3162
G4
5
G5
G3
capacitors and pull-up resistors connected to the MSD, NSD
and LSD outputs are there to shorten the digit drive signal
thereby providing proper timing for the CD4056B latches.
Inverters G1 and G2 are used as an astable multivibrator to
provide the AC drive to the LCD backplane. Inverters G3, G4
and G5 are the digit-select inverters and require pull-up
resistors to interface the open-collector outputs of the
CA3162E to CMOS logic. The BCD outputs of the CA3162E
may be connected directly to the corresponding CD4056B
inputs (using pull-up resistors). In this arrangement, the
CD4056B decodes the negative sign (-) as an “L” and the
positive overload indicator (E) as an “H”.
The circuit as shown in Figure 3 using G7, G8 and G9 will
decode the negative sign (-) as a negative sign (-), and the
positive overload indicator (E) as “H”.
G9
0.047
µF
0.047µF
100kΩ
1
6
4
2
3
5 7
1
6
4
2
3
5 7
1
6
4
2
3
5 7
CD4056B
CD4056B
CD4056B
16
16
16
15kΩ
8
8
8
+5V
0.63µF
+5V
+5V
TO MSD
OF LCD
TO NSD
OF LCD
TO LSD
OF LCD
BACKPLANE
TO LCD