MC34018

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

2 of 8

www.unisonic.com.tw

QW-R108-006,C

PIN CONFIGURATION

1

2

3

4

5

6

7

8

9

10

11

12

13

14

28

27

26

25

24

23

22

21

20

19

18

17

16

15

RR

RTX

TXI

TXO

TLI

TLO

RLI

RLO

MCI

MCO

CP1

CP2

XDI

SKG

RRX

RXI

RXO

ACF

XDC

GND

SKI

CS

AGC

V+

SKO

PIN DESCRIPTION

PIN NO.

PIN NAME

DESCRIPTION

1

RR

A resistor to ground provides a reference current for the transmit and receive attenuators

2

RTX

A resistor to ground determines the nominal gain of the transmit attenuator, the transmit

channel gain is inversely proportional to RTX resistance.

3

TXI

Transmit Attenuator Input, Input resistance is nominally 5.0kΩ.

4

TXO

Transmit Attenuator Output, The TXO output signal drivers the input of transmit level

detcetor, as well as the external circuit which drivers the telephone line.

5

TLI

Transmit Level detector Input. An external resistor ac coupled to The TLI pin sets the

detection level. Decreasing this resistor increases the sensitivity to transmit channel

signals.

6

TLO

Transmit Level detector Output. The external resistor and capacitor set the time the

comparator will hold the system in the transmit mode after speech ceases.

7

RLI

Receive Level detector Input. An external resistor ac coupled to The RLI pin sets the

detection level. Decreasing this resistor increases the sensitivity to receive channel signals.

8

RLO

Receive Level detector Output. The external resistor and capacitor set the time the

comparator will hold the system in the receive mode after speech ceases.

9

MCI

Microphone amplifier input. Input impedance is nominally 10kΩ and the dc bias voltage is

10

MCO

Microphone amplifier output. The MIC amp gain is internally set at 34dB (50V/V).

11

CP1

corresponding to the background noise level. The transmit detector compares the CP1

voltage with the speech signal from CP2.

12

CP2

A capacitor at this pin peak detects the speech signals for comparison with the background

noise level held at CP1.

13

XDI

Input to the transmit detector system. The microphone amplifier output is ac coupled to the

XDI pin through an external resistor.

14

SKG

High current ground pin for the speaker amplifier output stage. The SKG voltage should be

within 10mV of the ground voltage at pin 22.