LC75857E Datasheet, PDF (36/39 Pages) Sanyo Semicon Device – CMOS IC 1/3, 1/4 Duty LCD Display Drivers with Key Input Function

LC75857E, LC75857W
Sample Application Circuit 8
1/4 duty, 1/3 bias (for use with large panels)
+3V
10 kΩ ≥ R ≥ 1 kΩ
C ≥ 0.047 µF
+5V
*10
R
R
CC _R
From the controller
To the controller
To the controller
power supply
*12
VDD
VSS
TEST
VLCD
VLCD1
VLCD2
OSC
*11
COM1
COM2
COM3
S39/COM4
P1/S1
P2/S2
P3/S3
P4/S4
S5
CE
CL
DI K K K K K
DO
IIIII
54321
S38
SSS
444
210
///
KKKKKK
SSSSSS
654321
(P1) ^{(general-purpose output ports)}
(P2)
(P3) ^{Used with the backlight}
(P4) ^{controller or other circuit.}
(S40)
(S41)
(S42)
Key matrix
(up to 30 keys)
Notes:*10. Add a capacitor to the logic block power supply line so that the logic block power supply voltage V_DD rise time when power is applied and the logic
block power supply voltage V_DD fall time when power drops are both at least 1 ms, as the LC75857E/W is reset by the VDET.
*11. When RC oscillator mode is used, the external resistor Rosc and the external capacitor Cosc must be connected between the OSC pin and
ground, and when external clock mode is selected the current protection resistor Rg (4.7 to 47 kΩ) must be connected between the OSC pin and
the external clock output pin (external oscillator). (See the section on the OSC pin peripheral circuit.)
*12. The DO pin, being an open-drain output, requires a pull-up resistor. Select a resistance (between 1 to 10 kΩ) appropriate for the capacitance of
the external wiring so that signal waveforms are not degraded.
Notes on transferring display data from the controller
When using the LC75857E/W in 1/3 duty, applications transfer the display data (D1 to D126) in three operations, and in
1/4 duty, they transfer the display data (D1 to D164) in four operations. In either case, applications should transfer all of
the display data within 30 ms to maintain the quality of the displayed image.
No. 7980-36/39