For price, delivery, and to place orders, please contact Hittite Microwave Corporation:

2 Elizabeth Drive, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373

Order On-line at www.hittite.com

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HMC981

v00.0611

General Description

ACTIVE BIAS CONTROLLER

Functional Diagram

Typical Applications

HMC981 is an active bias controller that automatically

adjusts the gate voltage of an external amplifier

to achieve constant bias current. It can be used to

bias any enhancement and depletion type amplifiers

operating in Class-A regime with Drain voltages from

4V to 12V and drain currents up to 200mA, offering a

complete biasing solution.

HMC981 achieves excellent bias stability over supply,

temperature and process variations, and eliminates

the required calibration procedures usually employed

to prevent RF performance degradation due to such

variations.

All data shown herein is taken with appropriate probes.

• Microwave Radio & VSAT

• Military & Space

• Test Instrumentation

• Fiber Optic Modulator Driver Biasing

• CATV Laser Driver Biasing

• Cellular Base Station

• Wireless Infrastructure Equipment

Features

Automatic Gate voltage adjustment (No Calibration

required)

Supply Voltage: 4V to 12V

Digital Voltage: 3.3V to 5V

Controls both Enhancement and Depletion type

devices

Adjustable Drain Current up to 200mA

Sink/Source Gate Current Capability

Optional Internal negative voltage generation that

can be disabled to use external negative rail

Fast Enable/Disable

Trigger-out Output for Daisy Chain Power-Up and

Power-Down Sequencing