ANADIGICS AN-0002
This application note outlines some of the considerations for biasing MESFET amplifiers. For a typical device operating in Class A the desired current is 50% of the maximum current for any particular part.| Part No. | AN-0002 |
|---|---|
| Datasheet | AN-0002 Download |
| Manufacturer |  ANADIGICS |
| Description | Biasing Circuits and Considerations |
| Buy | Stock & Price |
MESFET Amplifier Biasing AN-0002 Biasing Circuits and Considerations for GaAs MESFET Power Amplifiers Summary In order to properly use any amplifier it is necessary to provide the correct operating environment, especially the DC bias. Items considered herein are:
● Constant current operation,
● Temperature compensation of the biasing network, and
● Power sequencing of the applied voltages. Overview The I-V curves of Figure 1 represent a typical MESFET device in a common source configuration. 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 becomes 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.
● Constant current operation,
● Temperature compensation of the biasing network, and
● Power sequencing of the applied voltages. Overview The I-V curves of Figure 1 represent a typical MESFET device in a common source configuration. 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 becomes 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.
