GL6965

15

Application

1. Transmitter

As the transmitter, ¨ çthe condenser microphone. ¨ èthe ceramic type and ¨ éthe dynamic type

(speaker type) are available. However, since ¨ çand ¨ èof FET or transistor built-in require the

bias circuit. Externally provide the bias circuit. For example, refer to the example of the application

circuit.

2. Receiver

As the receiver, ¨ ç

the ceramic type ¨ èthe low-impedance (dynamic type) are available.

(1) Ceramic type;

The receiver of equivalent capacity of about 55nF is assumed. In case of

the ceramic type, since the large voltage amplitude is generally required

at driving, make the receiver function in BTL mode.

(2) Low-impedance type; The receiver of equivalent resistance of about 150§ Ùis assumed. For the

connections, refer to the example of application circuit.

3. Example of Application circuit.

(1) EXAMPLE OF POWER SUPPLY CIRCUIT

FOR CONDENSER MICROPHONE

(2) EXAMPLE OF CONNECTION CIRCUIT OF

LOW-IMPEDANCE TYPE RECEIVER.

(3) In case of using transmit input amplifier as

non-inversion input.

(4) In case of using transmit input amplifier as in-

version input.

Note : In test circuit and application circuit, transmit

input amplifier is set at inversion input.

+

-

4.7

µF

18

510

Ω

19

R

LOW-

IMPEDANCE

TYPE RECEIVER

(150

Ω)

T

0.47

µF

TO MICROPHONE

INPUT

TO 13 PIN

0.47mF

6

330pF

2.2k§ Ù

_

+

TRANSMIT INPUT AMP

7

T

8

TRANSMITER

2.2k§ Ù

2.2k§ Ù1mF

TO 13 PIN

6

330pF

2.2k§ Ù

_

+

TRANSMIT INPUT AMP

7

T

8

TRANSMITER

2.2k§ Ù

2.2k§ Ù

0.47mF