SA2531 A/B/C/E/G/U
Pin# Symbol Function
25
CS
Current Shunt Control Output
This N-channel open drain output controls the external high power shunt
transistor for the modulation of the line voltage and for shorting the line
during make period of pulse dialling.
4
V
DD
Positive Voltage Supply
This is the supply pin for the circuit.
26
V
SS
Negative Power Supply
8
MO
Melody Output
Pulse Density Modulated output of the melody generator for tone ringer. At
high impedance when not active.
21
FCI
Frequency Comparator Input
This is a Schmitt trigger input for ring frequency discrimination. Disabled
during off-hook.
10
HS/DP
Hook Switch Input and Dial Pulse Output
This is an I/O that is pulled high by the hook switch when off- hook. An open
drain pulls it low during break periods of pulse dialling and flash.
11
OSC
Oscillator Input
Oscillator pin for Xtal or ceramic resonator (3.58 MHz). Recommended part
is the Murata CSA3.5MG312AM.
9
LLC
Line Loss Compensation
Select pin for the loss compensation.
OPEN = None
V
DD
= 45-75mA
V
DD
= 20-50mA
12
RR
Repetition Rate
Select pin for repetition rate of melody for the Tone rinser.
22
MODE
Signalling Mode Select Input
Mode pin Function
High
LD mode, 10pps, M:B = 33:66 (J:20pps)
Open
MFonly
Low
LD mode, 10pps, M:B = 40:60 (J:20pps, M:B = 33:66)
20
19
18
17
16
15
14
13
7
R1
R2
R3
R4
C1
C2
C3
C4
CI
Keyboard Rows
Keyboard Columns
Complex Impedance Input
Input pin for the capacitor in the complex impedance
sames
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SAMES [ SAMES ]
