7

Biasing and Operation

The AMMC-5023 has four cascaded gain stages as shown

in Figure 19. The first two gain stages at the input are

biased with the V

stages are biased with the V

eration is with a single positive DC drain supply voltage

(V

2(a).

If desired, the output stage DC supply voltage (V

be increased to improve output power capability while

maintaining optimum low noise bias conditions for the

input section. The output power may also be adjusted

by applying a positive voltage at V

ing bias point for both the output FETs. Increasing the

voltage applied to V

negative gate-to-source voltage and, therefore, lower

drain current. Figures 20(b) and 20(c) illustrate how the

device can be assembled for independent drain supply

operation and for output stage gate bias control.

Figure 19. AMMC-5023 Schematic.

Assembly Techniques

The backside of the MMIC chip is RF ground. For mi-

crostrip applications the chip should be attached directly

to the ground plane (e.g. circuit carrier or heatsink) using

the amount should be just enough to provide a thin fillet

around the bottom perimeter of the die. The ground

plane should be free of any residue that may jeopardize

electrical or mechanical attachment. Caution should be

taken to not exceed the Absolute Maximum Rating for

assembly temperature and time.

Thermosonic wedge bonding is the preferred method for

wire attachment to the bond pads. The RF connections

should be kept as short as possible to minimize induc-

tance. Gold mesh or double-bonding with 0.7 mil gold

wire is recommended.

Mesh can be attached using a 2 mil round tracking tool

and a tool force of approximately 22 grams with an ultra-

sonic power of roughly 55 dB for a duration of 76 ± 8 mS.

A guided wedge at an ultrasonic power level of 64 dB can

be used for the 0.7 mil wire. The recommended wire bond

stage temperature is 150 ± 2°C.

The chip is 100 mm thick and should be handled with

care. This MMIC has exposed air bridges on the top

surface. Handle at edges or with a custom collet (do not

pick up die with vacuum on die center.)

This MMIC is also static sensitive and ESD handling pre-

cautions should be taken.

Notes:

1. Ablebond 84-1 LM1 silver epoxy is recommended.

2. Eutectic attach is not recommended and may jeopardize reliability

of the device.

RF Input

RF Output