U3810BM Datasheet, PDF (8/31 Pages) TEMIC Semiconductors – Multi Standard Feature Phone Integrated Circuit

U3810BM
TELEFUNKEN Semiconductors
Pin description
Pin
Symbol
16
GND
17
RREF
18
CEI
19
RDC
20
AGA
21
MICX
22
MIC1
23
MIC2
24
ZAC
25
TO
26
MICO
27
TIN
28
TACL
29
RECO2
30
RECO1
31
RECOX
32
STL
33
RECI
34
STS
35
MF
36
D
Function
Ground.
External reference resistor. Connection for external reference resistor to generate the
reference current. All basic currents of the circuit which must satisfy certain absolute
accuracy requirements depend on this current.
Capacitor for electronic inductance. Connection for capacitor of the electronic coil.
The circuit contains a first order RC-active low-pass filter. The capacitor is connected
externally between CEI and VL.
DC characteristic slope adjustment. A voltage across resistor RDC is proportional to
the dc line voltage. This means the current flow through RDC is also proportional to
the line voltage. This current drives the supply currents drawn from VL by the most
important loads, and therefore defines the total current consumption of the circuit.
Adjustment to the slope characteristic is realized by modification of RDC resistance.
Line length adjustment. Reference voltage level for AGA. The potential at this point
defines the start threshold for the AGA and the automatic balancing in the receive part
(both can be switched off by the serial bus). The potential is normally formed between
VCC and ground using a voltage divider. When the line voltage exceeds the threshold
level, the AGA or balancing becomes effective.
Asymmetrical microphone input for special applications. The input of the first stage of
the transmit amplifier, selected by the serial bus. Anticlipping is not effective at this
input.
Inverting input of microphone amplifier.
Noninverting input of microphone amplifier.
AC impedance adjustment. Adjustment of the ac circuit impedance to the line by
changing of RZAC.
Transmit amplifier output. Transmit amplifier output modulates the current flowing
into this output (typically 4.8 mA).
Microphone amplifier output. Output MICO; open-circuit potential = 2*Vbe
Transmit and DTMF input. Input of the second transmit stage.
Adjustment of anticlipping time constant with external RC combination. Anticlipping
controls the transmitter input level to prevent clipping with high signal levels. The
dynamic range of the transmit peak limiter is controlled by an internal circuit.
Symmetrical output of receive amplifier.
Symmetrical output of receive amplifier.
Receive amplifier output for handsfree and answering machine applications.
Long line sidetone network.
Receive amplifier input. It is driven by a signal from VL.
Short line sidetone network.
Multifrequency output. Output DTMF signal and confidence tone in pulse–density
modulated form. DTMF signal and confidence tone are generated by special generators
in the digital part of the circuit. The DTMF signal consists of two weighted and
superimposed pulse-density modulated signals, while in the case of confidence tone, a
pulse–density modulated signal is superimposed on a high frequency rectangular–pulse
signal with pulse duty factor 0.5. The superimposed signals are sent out to MF for
further processing.
Data input of serial bus (see Pin 37). Serial data input from microprocessor for
programming the circuit.
8 (31)
Rev. A1: 19.01.1996