UNISONIC TECHNOLOGIES CO., LTD

U4082B

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

2 of 13

www.unisonic.com.tw

QW-R108-020.A

PIN DESCRIPTION

PIN NO

PIN NAME

DESCRIPTION

1

FO

Output of filter. The output impedance is less than 50Ω.

2

FI

Input of filter. The input impedance is less than 1MΩ.

3

CD

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.

4

2.8V, when in the receive mode, an AGC circuit reduces the receive attenuator gain by

25dB.

5

HTO+

The output of the second hybrid amplifier. This amplifier’s gain is internally set at -1.

6

HTO-

Output of the first hybrid amplifier. This amplifier’s gain of the amplifier is set by

external resistors.

7

HTI

The first hybrid amplifier’s input and summing node. DC level is about equal to VB.

8

TXO

The transmit attenuator’s output. DC level is about VB.

9

TXI

The transmit attenuator’s input. It’s maximum signal level is 350 mVrms. The input

impedance is 10KΩ.

10

MCO

The microphone amplifier’s output. This amplifier’s gain is set by external resistors.

11

MCI

The summing node of the microphone’s input. DC lever is VB.

12

MUT

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.

13

VLC

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.

14

CT

At this pin, to switch modes, the RC sets the response time for the circuit.

15

VB

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.

16

CPT

The time constant for the transmit background side can be set by the RC at this pin .

17

TLI2

The input to the transmit level detector which is on the microphone/ speaker side.

18

TLO2

The output to the transmit level detector which is on the microphone/ speaker side.

Also the input to the transmit background monitor.

19

RLO2

The Output of the receive level detector which is on the microphone/ speaker side

20

RLI2

The input to the receive level detector which is on the microphone/ speaker side

21

RXI

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.

22

RXO

The output of the receive attenuator. This pin’s DC level is VB.

23

TLI1

The input to the transmit level detector which is on the line side.

24

TLO1

The output to the transmit level detector which is on the line side, and also the input to

the transmit background monitor.

25

RLO1

The output of the receive level detector which is on the line side.

26

RLI1

The input to the receive level detector which is on the line side.

27

CPR

The time constant for the receive background monitor can be set by the RC at this pin.

28

GND

Ground.