CHA2095a

36-40GHz Low Noise Amplifier

Ref. : DSCHA20958147-27 May 08

6/6

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

Vg1,2

Vg3,4

Vd

100

100

50

50

For low noise operation, a separate access to the gate voltages of the two first stages (Vg1,

2), and of the two last stage (Vg3,4) is provided. Nominal bias is obtained for a typical

current of 60 mA for the output stages and 30 mA for the two first stages (90 mA for the

amplifier).

The first step to bias the amplifier is to tune Vg1, 2 = -1V, and Vg3, 4 to drive 60 mA for the

full amplifier. Then Vg1,2 is increased to obtain 90 mA of current through the amplifier. A fine

tuning of the noise figure may be obtained by modifying the Vg1, 2 bias voltage, but keeping

the previous value for Vg3, 4.

It is possible to reduce the total DC current by biasing Vg3, 4 to a more negative value. The

consequences will be a reduction of gain and of the output power capabilities of the

amplifier.

Vd could be adjust in such a way that the Vds (Drain to Source voltage of the internal

transistor) is kept below 3.5V, knowing that all the transistors have the same size, and with

the given resistors.

Ordering Information

Chip form

:

CHA2095a99F/00

Information furnished is believed to be accurate and reliable. However United Monolithic Semiconductors

S.A.S. assumes no responsibility for the consequences of use of such information nor for any infringement of

patents or other rights of third parties which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of United Monolithic Semiconductors S.A.S.. Specifications

mentioned in this publication are subject to change without notice. This publication supersedes and replaces all

information previously supplied. United Monolithic Semiconductors S.A.S. products are not authorised for use

as critical components in life support devices or systems without express written approval from United

Monolithic Semiconductors S.A.S.