SKY65120 Datasheet (Skyworks Solutions)

SKY65120, WCDMA PA Bias Method

The active circuit is designed to maintain a constant supply current to the base of its respective transistor as supply voltage and temperature is changed.

Each active bias circuit consists of three HBT transistors and three resistors, connected as shown in Figure 2 below.

VC_BIAS R1 Q1 Q2 R2 I_S

application note SKY65120: WCDMA PA Bias Method For Lower Junction Temperature Introduction This application note describes how SKY65120 may be used with reduced bias control to obtain better thermal performance.

It is especially useful for customers who may not have a suitable heat sink available directly below the PA module.

To achieve high gain (>23 dB), the SKY65120 consists of two stages of amplification.

The base current of each amplification stage is controlled by an on-die active bias c

SKY65120 Features

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