U4090B Datasheet, PDF (7/34 Pages) TEMIC Semiconductors – Monolithic Integrated Feature Phone Circuit

U4090B
Pin Symbol
Function
17 VRING Input for ringing signal protected by
internal zener diode
18 THA Threshold adjustment for ringing
frequency detector
19 RFDO Output of ringing frequency detector
20 LIDET Line detect; output is low when the
line current is more than 15 mA
21 IMP- Control input for selection of line
SEL impedance
1. 600 Ω
2. 900 Ω
3. Mute of second transmit stage
(TXA); also used for indication of
external supply (answering machine);
last chosen impedance is stored
22 TSACL Time constant of anti-clipping of
speaker amplifier
23 GSA Current input for setting the gain of
the speaker amplifier,
adjustment characteristic is
logarithmical,
or RGSA > 2 MΩ, the speaker
amplifier is switched off
24 SA I Speaker amplifier input (for
loudspeaker, tone ringer and
handsfree use)
25 MUTX Three state input of transmit mute:
1) Speech condition; inputs MIC1 /
MIC2 active
2) DTMF condition; input DTMF
active
a part of the input signal is
passed to the receiving amplifier
as a confidence signal during
dialing
3) Input DTMF used for answering
machine and handsfree use;
receive branch not affected
26 ATAFS Attenuation of acoustical feedback
suppression,
maximum attenuation of AFS circuit
is set by a resistor at this pin,
without the resistor, AFS is switched
off
27 INLDT Input of transmit level detector
28 INLDR Input of receive level detector
Pin Symbol
Function
29 TLDT Time constant of transmit level
detector
30 TLDR Time constant of receive level
detector
31 AGA Automatic gain adjustment with line
current
a resistor connected from this pin to
GND sets the starting point
max. gain change: 6 dB.
32 IREF Internal reference current generation;
RREF = 62 kΩ; IREF = 20 µA
33 STO Side tone reduction output
output resistance is approx. 300 Ω,
maximum load impedance: 10 kΩ.
34 V_M Reference node for microphone-
earphone and loudspeaker amplifier,
m ^{supply for electret microphone}
(IM ≤ 700 A)
35 MUTR Three state mute input
1. Normal operation
2. Mute of ear piece
3. Mute of RECIN signal
Condition of earpiece mute is stored
36 RECO 2 Inverting output of receiving
amplifier
37 STI S Input for side tone network (short
loop) or for answering machine
38 STI L Input for side tone network (long
loop)
39 RAC Input of receiving amplifier for ac
coupling in feedback path
40 RECO 1 Output of receiving amplifier
41 G_R A resistor connected from this pin to
GND sets the receiving amplification
of the circuit; amplifier RA1 can be
muted by applying VMP to GR
42 TTXA Time constant of anticlipping in
transmit path
W 43 RECIN Input of receiving path; input
impedance is typically 80 k
44 TXIN Input of intermediate transmit stage,
input resistance is typically 20 kΩ
TELEFUNKEN Semiconductors
7 (34)
Rev. C1, 28-Oct-96
Preliminary Information