MICROWAVE CORPORATION

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

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

Order Online at www.hittite.com

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HMC424

0.5dB LSB GaAs MMIC 6-BIT DIGITAL

ATTENUATOR, DC - 13 GHz

v02.0404

Simple driver using inexpensive standard logic ICs provides fast switching using minimum DC current.

* Recommended value to suppress unwanted RF signals at V1 - V6 control lines.

Mounting & Bonding Techniques for Millimeterwave GaAs MMICs

The die should be attached directly to the ground plane eutectically or with conductive epoxy (see HMC general Handling,

Mounting, Bonding Note).

50 Ohm Microstrip transmission lines on 0.127mm (5 mil) thick alumina thin film substrates are recommended for bringing RF

to and from the chip (Figure 1). If 0.254mm (10 mil) thick alumina thin film substrates must be used, the die should be raised

0.150mm (6 mils) so that the surface of the die is coplanar with the surface of the substrate. One way to accomplish this is to

attach the 0.102mm (4 mil) thick die to a 0.150mm (6 mil) thick molybdenum heat spreader (moly-tab) which is then attached

to the ground plane (Figure 2).

Microstrip substrates should be brought as close to the die as possible in order to minimize bond wire length. Typical die-to-

substrate spacing is 0.076mm to 0.152 mm (3 to 6 mils).

Assembly Diagram