Preliminary
Pin #
18
19
Symbol
CI
RECI
Type
AI
AI
Description
AS2525
C
omplex
I
mpedance Input
Analogue input pin for the capacitor to program a complex impedance.
RECeive Input
Analogue input for the handsfree receive path. Should be connected to RO via
a coupling capacitor.
RECeive Voice
Switching Input
Analogue input for receive voice switching path.
20
21
22
23
24
25
RECV
RO
V
DD
A
GND
CBN
CM
AI
AO
Supply
Supply
AI
DO
R
eceive
O
utput to
H
andset
Output for driving a dynamic earpiece with an impedance from 150
Ω
to 300
Ω
.
V
oltage
D
rain
D
rain
Positive Power Supply.
A
nalogue
G
round
Special ground for the internal amplifiers.
Analogue input pin for connecting a capacitor for background noise monitoring.
C
onverter
M
ake Output
This is an output for controlling the external switching converter. During ringing
it converts the ring signal into a 4V supply voltage.
26
27
28
29
30
V
PP
LO1
LO2
V
SSA
DM/HM
Supply
AO
Supply
DI
Loudspeaker Power Supply
High power supply for the output driver stage.
L
oudspeaker
O
utputs
1/2
Output pins for a 32
Ω
( 25 to 50
Ω
) loudspeaker.
Power supply pin for LO1-LO2 output amplifier.
D
ial
M
ode/
H
eadset
M
ode Switch Input
Digital input for choosing between LD and MF dialling or choosing handset and
headset mode. See “Table 3: Parameter settings” for further details. This pin is
scanned after manual off-hook only.
31
FCI
DI
F
requency
C
omperator
I
nput
This is a Schmitt-trigger input for ring frequency discrimination. Disabled during
off-hook.
32
33
34
35
36
37
38
39
40
41
LED
OSC
R1
R2
R3
C1
C2
C3
C4
CLK
DO
LED
Output
Digital output for connecting 2 mA LED to indicate handsfree mode.
O
scillator
Input
Input for ceramic resonator 3.58 MHz.
DI/O
Keyboard
R
ows
(see Figure 4: Keyboard Layout).
Keyboard
C
olumns
(see Figure 4: Keyboard Layout).
DI/O
DO
Cl
oc
k
Clock output for 3-wire bus.
If signal is not activated, a pull down resistor (100 k
Ω
) is inserted.
Rev. 1.3
Page 3
May 1999
AMSCO [ AUSTRIAMICROSYSTEMS AG ]
