AN-0002
Overview
The I-V curves of Figure 1 represent a typical MESFET device in a mon source configuration. For a typical device operating in Class A the desired current is 50% of the maximum current for any particular part. Typical MESFET devices are depletion mode, meaning that the highest drain-source current occurs for a gate voltage of approximately zero (Vgg ~ +0.5 V). As the gate voltage bees more negative, the device current drops and eventually approaches zero at the pinch-off voltage. The two main variables in the production of MESFET power amplifiers are the maximum current and the pinch-off voltage. Since the operating voltage is assumed to be fixed by the available voltages in the system, it is the drain current that should be monitored and controlled in order to provide consistent performance from unit to unit.
1.0 m1
Ids.i, A
0.6 m1 Vdd=1.200 Vgg=0.000 Ids.i=0.869 m2 m2 Vdd=7.000 Vgg=-1.100 Ids.i=0.337
0 2 4 6 8 10
Vdd
Figure 1. IV characteristics of...
