¡ Semiconductor

MSM7578H/7578V/7579

4/18

PIN AND FUNCTIONAL DESCRIPTIONS

AIN+, AIN–, GSX

Transmit analog input and transmit level adjustment.

AIN+ is a non-inverting input to the op-amp; AIN– is an inverting input to the op-amp; GSX is

connected to the output of the op-amp and is used to adjust the level, as shown below.

When not using AIN– and AIN+, connect AIN– to GSX and AIN+ to SG. During power saving

and power down modes, the GSX output is at AG voltage.

–

+

AIN–

AIN+

C1

Analog input

1) Inverting input type

R1 : variable

R2 > 20 kW

C1 > 1/(2 ¥ 3.14 ¥ 30 ¥ R1)

Gain = R2/R1 £ 10

R2

GSX

SG

+

–

AIN+

AIN–

2) Non inverting input type

R3 > 20 kW

R4 > 20 kW

R5 > 50 kW

C2 > 1/ (2 ¥ 3.14 ¥ 30 ¥ R5)

Gain = 1 + R4 / R3 £ 10

R4

GSX

SG

C2

Analog input

R3

R5

R1

AG

Analog signal ground.

AOUT

Analog output.

The output load resistance is a minimum of 600 W.

During power saving, or power down mode, the output of AOUT is at the voltage level of the

signal ground.