U4082B_15 Datasheet, PDF (2/13 Pages) Unisonic Technologies – VOICE SWITCHED SPEAKER-PHONE CIRCUIT

UNISONIC TECHNOLOGIES CO., LTD
U4082B
LINEAR INTEGRATED CIRCUIT
„ PIN DESCRIPTION
PIN NO
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
PIN NAME
FO
FI
CD
V_CC
HTO+
HTO-
HTI
TXO
TXI
MCO
MCI
MUT
VLC
CT
VB
CPT
TLI2
TLO2
RLO2
RLI2
RXI
RXO
TLI1
TLO1
RLO1
RLI1
CPR
GND
DESCRIPTION
Output of filter. The output impedance is less than 50Ω.
Input of filter. The input impedance is less than 1MΩ.
Chip Disable input .A logic low (voltage lower than 0.8V) sets normal operation. A logic
high (voltage higher than 2V) disable the IC. This pin’s input impedance is 90 KΩ
nominally.
This pin requires a supply voltage of +2.8V ~ +6.5V at 5mA. After V_CC falls from 3.5V ~
2.8V, when in the receive mode, an AGC circuit reduces the receive attenuator gain by
25dB.
The output of the second hybrid amplifier. This amplifier’s gain is internally set at -1.
Output of the first hybrid amplifier. This amplifier’s gain of the amplifier is set by
external resistors.
The first hybrid amplifier’s input and summing node. DC level is about equal to VB.
The transmit attenuator’s output. DC level is about VB.
The transmit attenuator’s input. It’s maximum signal level is 350 mVrms. The input
impedance is 10KΩ.
The microphone amplifier’s output. This amplifier’s gain is set by external resistors.
The summing node of the microphone’s input. DC lever is VB.
Input of mute. A logic low (voltage lower than 0.8V) sets the circuit normal operation. A
logic high (voltage higher than 2V) mutes the microphone amplifier, but it doesn’t affect
the rest of the circuit. The input impedance is 90 K ohms.
The input of Volume control. In the receive mode, when VLC=VB, the receive
attenuator is at maximum gain. The receive gain is down 35dB when VLC=0.3dB, and
it does not effect the transmit modes.
At this pin, to switch modes, the RC sets the response time for the circuit.
In this pin, there’s an output voltage=Vcc/2 which is a system AC ground and biases
the volume control. What required is a filter capacitor.
The time constant for the transmit background side can be set by the RC at this pin .
The input to the transmit level detector which is on the microphone/ speaker side.
The output to the transmit level detector which is on the microphone/ speaker side.
Also the input to the transmit background monitor.
The Output of the receive level detector which is on the microphone/ speaker side
The input to the receive level detector which is on the microphone/ speaker side
The input to the receive attenuator and dial tone detector. In this pin, the maximum
input level is 350mVrms,and the input impedance is 10KΩ.
The output of the receive attenuator. This pin’s DC level is VB.
The input to the transmit level detector which is on the line side.
The output to the transmit level detector which is on the line side, and also the input to
the transmit background monitor.
The output of the receive level detector which is on the line side.
The input to the receive level detector which is on the line side.
The time constant for the receive background monitor can be set by the RC at this pin.
Ground.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
2 of 13
QW-R108-020.A