CTCSS Signalling Processor
FX818
1.3
Signal List
(continued)
Signal
Name
NC
NC
A/D CAP
O/P
Type
) No internal connection. Do not make
) any connection to these pins.
An internal reference voltage for the A to D,
decoupled to V
SS
by an external capacitor.
No internal connection. Do not make any
connection to this pin.
Power
O/P
The negative supply rail (ground).
A bias line for the internal circuitry, held at ½
V
DD
. This pin must be decoupled by a capacitor
mounted close to the device pins.
The inverting input to the Rx input amplifier.
The output of the Rx input amplifier and the input
to the audio filter section.
Output of the Rx audio filter section.
No internal connection. Do not make any
connection to this pin.
I/P
O/P
I/P
O/P
O/P
O/P
Power
Input to the audio summing amplifier.
Output of the audio summing amplifier.
Input to MOD1 audio gain control.
Output of the CTCSS tone generator.
Output of MOD1 audio gain control.
Output of MOD2 audio gain control.
The positive supply rail. Levels and voltages are
dependent upon this supply. This pin should be
decoupled to V
SS
by a capacitor.
Description
Package
D2/D5
Pin No.
8
9
10
11
NC
12
13
Vss
V
BIAS
14
15
RX AMP IN
RX AMP OUT
I/P
O/P
16
17
RX AUDIO OUT
NC
O/P
18
19
20
21
22
23
24
SUM IN
SUM OUT
MOD1 IN
TX SUB AUDIO OUT
MOD1
MOD2
V
DD
Notes:
I/P =
O/P =
Input
Output
©
1997
Consumer Microcircuits Limited
5
D/818/4
CMLMICRO [ CML MICROCIRCUITS ]
