20-40GHz Variable Gain Amplifier

CHA2097a

Ref. : DSCHA20978021

7/8

Specifications subject to change without notice

Route Départementale 128 , B.P.46 - 91401 ORSAY Cedex - FRANCE

Tel.: +33 (0)1 69 33 03 08 - Fax : +33 (0)1 69 33 03 09

Typical Bias Tuning

The circuit schematic is given below :

Attenuator

IN

OUT

Vd2,3

Vg 3

Vg1

Vd1

Vg 2

Vctrl

For gain control operation, The three drain biases are connected altogether. In a same way, all the

gate biases are connected together at the same power supply, tuned to drive a small signal operating

current of 140mA. A separate access to the gate voltages of each stages ( Vg1,2,3 ) is provided for

fine tuning of the stages regarding the application.

An additional pad is provided ( Vctrl ) to control the gain of the circuit, driving two cold transistors in

attenuator arrangement.