U3760MB Datasheet, PDF (5/19 Pages) TEMIC Semiconductors – Low-Voltage Standard Telephone Circuit

U3760MB
SDIP40 SSO44
10
13
Symbol
Function
MIC 1 Inverting input of microphone
amplifier
11
14
MIC 2 Non-inverting input of microphone
amplifier
Configuration
MIC1
MIC2
1V
50K
50K
1V
Ê^VI
PD
ÊÊ_VI
12
15
MICO Transmit pre-amp output which is
normally capacitively coupled to
Pin TIN
MICO
ÊPD
VI
Ê Ê1V
16K
13
16
PD
VL Positive supply voltage input to the
device. The current through this
VL
16V
pin is modulated by the transmit
PD
signal.
RDC
PD
14
17
RDC An external resistor (1 W) is
required from this pin to GND to
control the dc input impedance of
Ê^VL
the circuit. It has a nominal value
W of 39 for low-voltage operation.
AGC
W Values up to 100 may be used to
increase the available transmit
PD
output voltage swing at the expense RDC
PD
of low-voltage operation.
16
18
TIN Input to the line output driver am-
plifier. Transmit AGC is applied to
this stage.
ÊÊ^1V
5.6K
TIN
ÊÊ ^16V
PD
17
19
V_I This internal voltage bias line must
be connected to VL via an external
resistor, R_B, which dominates the
ac input impedance of the circuit
W and should be 680 Ω for 600-
input impedance or 1.2 kΩ for a
900-Ω input impedance.
Ê
VI
16V
PD
Rev. A3, 19-Feb-98
5 (19)