AN3336SB
s
Functional Descriptions
1. Playback mode
•
Pin36 (playback V
CC
) = 5V typ. (Pins15 and 17 are grounded internally)
•
Pin18 (recording V
CC
) = open
(1) Selecting a head amplifier output channel
ICs for VCR
Channel
Input pin
Head SW Pin
1
HASW Pin
34
1
SP
2
3
LP
4
4
6
11
13
H
L
L
H
L
L
H
H
(2) Starting the envelope comparator
Env. ON/OFF SW
Pin2
Env. comparator
Open
Inactive
Low (special playback)
Active
(3) Automatic tracking interface
Pin24 (automatic tracking V
CC
) = 5V typ.
• When the SP mode of the automatic tracking
interface switches to the LP mode, the gain of
the amplifier increases 5.5dB.
• When the gain control voltage at Pin23 increases,
the gain of the circuit increases.
HASW(Pin24)
High
Low
Automatic tracking
LP
SP
4
PANASONIC [ PANASONIC SEMICONDUCTOR ]
