U3761MB
Low Voltage Standard Telephone Circuit with 13 Memories
Description
TEMIC’s low voltage telephone circuit, U3761MB
performs all the speech and line interface functions
required in an electronic telephone set, the tone ringer, the
pulse and DTMF dialing with redial, notice function, and
13 memories.
Features
Speech Circuit
D
Last number redial up to 32 digits
D
Three by 32 digits direct (one touch) memory
D
Ten by 16 digits indirect (two touch) memory
D
Notice function up to 32 digits
D
Standard low-cost crystal 3.57 MHz or
ceramic resonator
D
Adjustable DC characteristic
D
Symmetrical input of microphone amplifier
D
Receiving amplifier for dynamic or
piezo-electric earpieces
D
Automatic line loss compensation
Dialer
D
DTMF / pulse switchable
D
Pulse dialling 66/33 or 60/40 or DTMF dialling
selectable by pin
Tone Ringer
D
2 Tone ringer
D
Adjustable volume
D
RC oscillator
D
Adjustable threshold
D
Selectable flashing duration by key pad
D
Pause function
Benefits
D
Low number of external components
D
High quality through one IC solution
TELEFUNKEN Semiconductors
Rev. A2, 23-Apr-97
1 (23)
Preliminary Information
U3761MB
Pin Description
SDIP40
1
2
3
4
5
15
6
SSO44
1
2
3
4
5
7, 6,
34, 35
8
Symbol
C1
C1
Configuration
Function
Keyboard input
C2
PD
C3
C2–C4
C4
Earth
NC
XT
XT
PD
PD
Earth key
Not connected
A built-in inverter provides
oscillation with an inexpensive
3.579545 MHz crystal or ceramic
resonator
40P
PD
40P
XT
7
9
XT
XT
PD
XT
40P
PD
40P
8
10
MFO
Output of DTMF
DTMF output frequency
Specified Actual
(HZ)
(Hz)
R1
697
699
R2
770
766
R3
852
848
R4
941
948
C1
1209
1216
C2
1336
1332
C3
1477
1472
Ground
MFO
Error
(%)
+0.28
–0.52
–0.47
+0.74
+0.57
–0.30
–0.34
9
12
GND
4 (23)
Preliminary Information
TELEFUNKEN Semiconductors
Rev. A2, 23-Apr-97
U3761MB
SDIP40
10
SSO44
13
Symbol
MIC 1
Configuration
VI
1V
50K
Function
Inverting input of microphone
amplifier
MIC1
MIC2
1V
11
14
MIC 2
1V
50K
MIC1
MIC2
50K
1V
12
15
MICO
MICO
PD
13
16
VL
VL
PD
16V
RDC
TELEFUNKEN Semiconductors
Rev. A2, 23-Apr-97
Preliminary Information
Ê
Ê
ÊÊ
Ê
Ê
Ê
Ê
Ê
Ê
Ê
Ê
VI
VI
VI
50K
Ê
PD
PD
Non-inverting input of microphone
amplifier
PD
PD
VI
1V
Transmit pre-amp output which is
normally capacitively coupled to
Pin TIN
16K
Positive supply voltage input to the
device. The current through this
pin is modulated by the transmit
signal.
PD
5 (23)