U3750BM
TELEFUNKEN Semiconductors
Pin Description
Pin
1
2
3
4
Symbol Function
Pin
23
24
25
26
27
Symbol Function
MIC Microphone input
Dynamic impedance adjustment
EM/FILT First sending stage output
MOD Modulator output
C4
C3
Keyboard input
Keyboard input
2
ZAC
FLASH Flashing selection
DC/FV Dialling selection (33/66 pulse,
40/60 pulse or DTMF)
EM/MF Second sending stage input and
DTMF input
5
6
7
OL
Open line output
RESET Output reset
TEEIN Test pins
28
ACL
Anticlipping time constant
adjustment
29
30
31
32
33
34
35
36
37
38
E2
E1
NC
REC
ZAL
OUT1
OUT2
VIR
CK
Receiver output
Receiver output
Not connected
Receiver input
Sidetone network
Buzzer output
Buzzer output
Ringing supply
Ceramic input (455 KHz)
Adjustment between two pairs of
ringing frequencies
Beat adjustment of each pair of
ringing frequencies
8
9
SHEN
NC
Test pins
Not connected
RAM and internal logic supply
Power supply for peripherals
Line voltage
10
11
12
13
14
V
RAM
V
CC
V
L
OSCAB Test pin
EC Extra current for peripherals or
can be used to dissipate power
for high line current applications.
15
16
17
18
19
20
21
TESTR Test pin
GND
NC
PAIR
Ground
Not connected
39
BEAT
AGA
Line length AGC adjustment
Bias adjustment
Electronic self input
DC characteristic slope
adjustment
40
41
42
43
44
MF
C1
C2
C6
C5
DTMF output
I
REF
Keyboard inputs
Keyboard inputs
Keyboard inputs
Keyboard inputs
SELF
RGAB
22
MIC
Microphone input
1
Rev. A1: 16.07.1996
3 (20)
TEMIC [ TEMIC SEMICONDUCTORS ]
