Pin Assignment
No. 5729-2/23
LC74786, 74786M, 74786JM
Pin Functions
Pin No.
Pin Name
Function
Notes
1
V
SS
1
Xtal
IN
Ground
Ground connection (digital system ground)
2
These pins are used either to connect the crystal and capacitors used to form an external
crystal oscillator circuit to generate the internal synchronizing signals, or to input an external
clock signal (2fsc or 4fsc). As a mask option, the Xtal
OUT
pin can be set to function as the
MUTE input pin. When this pin is set low, the video output is held at the pedestal level. (A pull-
up resistor is built in and the input has hysteresis characteristics.)
Crystal oscillator
(MUTE input)
Xtal
OUT
(MUTE)
3
Switches the mode between external clock input and crystal oscillator operation. A low level
selects crystal oscillator operation and a high level selects external clock input. As a mask
option, the CTRL1 input pin can be set to function as the CHABLK (character · frame) output.
This is a 3-value output.
4
CTRL1
(CHABLK)
Crystal oscillator input switching
(CHABLK output)
5
HFTON
OUT
Background line output
Outputs the range signal specified by LNA
*
, LNB
*
, and LNC
*
. Outputs the crystal oscillator
clock when RST is low. (This signal is not output after a reset command is executed.)
6
OSC
IN
OSC
OUT
LC oscillator
Connections for the inductor and capacitor that form the character output dot clock generation
oscillator.
7
Outputs the state of the external synchronizing signal presence/absence judgment. Outputs a
high level when synchronizing signals are present.
Outputs the dot clock (LC oscillator) when RST is low. (This signal is not output on command
resets.)
8
SYNC
JDG
External synchronizing signal
judgment output
9
CS
Enable input
Serial data input circuit enable pin. Serial data input is enabled when a low level is input.
A pull-up resistor is built in. (This input has hysteresis characteristics.)
10
SCLK
Clock input
Serial data input circuit clock input.
A pull-up resistor is built in. (This input has hysteresis characteristics.)
11
SIN
Data input
Serial data input.
A pull-up resistor is built in. (This input has hysteresis characteristics.)
12
V
DD
2
Power supply
Composite video signal level adjustment power supply (analog system power supply)
Continued on next page.