TELEFUNKEN Semiconductors
U3810BM
Pin description
Pin
1
2
3
4
5
Symbol
RPI
VRI
IMPA
COS
IOS
Function
Ringing power information. The RC combination smooths the drive current of the
loudspeaker amplifier.
Tone-ringer supply voltage. The rectified ringing voltage is delivered to VRI and then
converted into the lower supply voltage, VSA, by the converter.
External adjustment of input ringing impedance. IMPA is adjusted with a resistance
between pin 2 and 3.
ZIN = RIN/100
Control output switching supply. COS drives the base of the external switching transis-
tor of the converter.
Current output of switching supply. This output provides a constant current, which
supplies the external part of converter. The magnitude of the current depends on the
VRI voltage and the value of resistance RIN.
Adjustment of antidistortion time constant in loudhearing with external RC
combination.
Adjustment of antilarsen time constant in loudhearing with external RC combination.
External logic supply.
Power supply for peripherals. VCC and VDD are stabilized supply voltages buffered
with external capacitors. They are derived internally from the same voltage source, but
are separated from each other by electronic switches. VDD also supplies the digital
part of the circuit and is achieved in all three modes: speech mode, ringing mode and
operation with external supply. According to the application, peripherial modules are
connected to VDD which, in addition to speech mode, must be supplied at least in one
of the two other modes. The digital part of circuit and microprocessor must continue
operating during line breaks, as they occur during pulse dialing or during flash-signal
transmission. Since VDD in this time intervals is fed only from the buffer capacity, the
power consumption from VDD must not cause the total voltage dump. VCC supplies
no internal parts of circuit and is supplied exclusively in speech mode. External
components, which must operate only in this mode, can be connected here. The power
is drawn only from the relevant buffer capacitor in the supply intervals during pulse
dialing or flash-signal transmission.
Line voltage.
Speaker amplifier input. The signal coming from the receive part, e.g. from REC01 or
RECO2, is fed in here.
Speaker amplifier input for special application i.e. answering machine. SAIX is
selected via the serial bus. SAIX has to be selected for ringing. IF ringing, Antidistor-
tion and Antilarsen are disabled.
Supply voltage for the loudhearing amplifier. Stabilized supply voltage buffered with
an external capacitor for the loudhearing amplifier and zero crossing detector; aditional
connection point for an external supply. In speech mode, VSA is supplied by the
analog part of the circuit. In this case, the stabilization point is adjusted to the DC line
voltage VSA= VL/1.5. In ringing mode, and VSA is supplied directly from the con-
verter. The stabilization point is permanently set. The logic supply, VDD, is fed by a
switch from VSA. VSA=5.2V. In the case of an external supply, VSA serves as a point
for a current from a power supply. The stabilization point of VSA and supply for the
logic correspond to the operation conditions in ringing mode.
Loudspeaker output 1.
Loudspeaker output 2. Differential output of loudhearing amplifier. The loudspeaker
can also be connected asymmetrically to ground or to VSA via a capacitor at one of the
two outputs. As a result of this connection there is a bigger output power in reference
to low line currents and loudspeakers with low impedance, while the differential
connection method results in a higher power output and lower harmonic distortion with
medium or high line currents and/or loudspeaker impedances
7 (31)
6
7
8
9
TAD
TAL
VDD
VCC
10
11
12
VL
SAI
SAIX
13
VSA
14
15
SO1
SO2
Rev. A1: 19.01.1996
TEMIC [ TEMIC SEMICONDUCTORS ]
