cf8224c Nippon Precision Circuits Inc, (NPC), cf8224c Datasheet - Page 4

• Manufacturer Part Number: cf8224c
• Description: Dual-tone Receiver Ic
• Manufacturer: Nippon Precision Circuits Inc, (NPC)

PIN DESCRIPTION
Number
10
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
OSCOUT
DTDET
OSCIN
MODE
Name
AGND
DOUT
CDET
RING
TEST
TRQ
GND
VDD
DTQ
STR
DT2
DT1
TIP
CR
S1
S0
I/O
I/O
O
O
O
O
O
O
O
O
–
–
–
I
I
I
I
I
I
I
I
Reference voltage output. Internal reference voltage (V
Tip input. Connected to the telephone line through a protection circuit
Ring input. Connected to the telephone line through a protection circuit
Input-stage amplifier gain-select output. Used to adjust the gain of the input-stage amplifier.
Ground. Connected to the system ground potential.
Crystal oscillator input. The crystal oscillator element is connected between this pin and OSCOUT.
Crystal oscillator output. The crystal oscillator element is connected between this pin and OSCIN.
When MODE is HIGH, and S1 and S0 are both LOW, the device is in power-down state. See table 2.
TEST pin. Set OPEN when normal using.
Data output. Demodulated FSK signal output. HIGH level output when CDET goes HIGH.
Dual-tone confirmation output. Function is selected by S0 and S1. See table 2.
Dual-tone confirmation: Active-LOW output when dual tone detection signal passes through RC time
constant delay circuit.
Dual-tone detector output. HIGH-level output when dual tone is detected.
Dual tone RC time constant circuit connection. The dual tone detection signal passes through the RC
network to generate the STR signal.
FSK signal carrier detector output. LOW-level when active carrier is detected.
Supply
Function select bit 1. Selects the device mode in combination with S0 and MODE. See table 2.
Function select bit 1. Selects the device mode in combination with S1 and MODE. See table 2.
Dual-tone signal input-stage amplifier output. Used to adjust the gain of the input-stage amplifier.
Dual-tone signal input-stage operational amplifier inverting input
Dual-tone signal input-stage operational amplifier non-inverting input
SM8224C
Function
DD
/2) output level
SEIKO NPC CORPORATION —4