CHA2094b
36-40GHz Low Noise Amplifier
Typical Bias Tuning for Low Noise Operation
The circuit schematic is given below :
Vd
100
IN
100
50
OUT
Vg 1,2
Vg 3
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.
Ref. : DSCHA20949312 – 08-Nov.-99
6/8
Specifications subject to change without notice
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UMS [ UNITED MONOLITHIC SEMICONDUCTORS ]
