CHA2094b

36-40GHz Low Noise Amplifier

Ref. : DSCHA20949312 – 08-Nov.-99

6/8

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 for Low Noise Operation

The circuit schematic is given below:

IN

OUT

Vd

Vg 1,2

Vg 3

100

100

50

For low noise operation, a separate access to the gate voltages of the two first stages (Vgs1&2), and of

the output stage (Vgs3) is provided.

Nominal bias for low noise operation is obtained for a typical current of 20 mA for the output stage and

15 mA for each of the two first stages (50 mA for the amplifier).

The first step to bias the amplifier is to tune the Vgs1&2 = -1V, and Vgs3 to drive 20 mA for the full

amplifier. Then Vgs1&2 is reduced to obtain 50 mA of current through the amplifier.

A fine tuning of the noise figure may be obtained by modifying the Vgs1&2 bias voltage, but keeping

the previous value for Vgs3.