AMMC-6345-W50 View Datasheet(PDF) - Avago Technologies

Part Name

Description

Manufacturer

AMMC-6345-W50

20 – 45 GHz Driver Amplifer

Avago Technologies 

Biasing and Operation

AMMC-6345 has quite flexible drain biasing conditions.

Recommended quiescent DC bias condition for optimum

power and linearity performances is Vd=5 volts with

Vg set for Id=480 mA. For high gain applications, the

AMMC-6345 can be biased at Vd=3V. Minor improve-

ments in performance are possible depending on the

application. The drain bias voltage range is 3 to 5.5V. A

single DC gate supply connected to Vg will bias all gain

stages. Muting can be accomplished by setting Vg to the

pinch-off voltage Vp.

An optional output power detector network is also

provided. The differential voltage between the Det-Ref

and Det-Out pads can be correlated with the RF power

emerging from the RF output port. The detected voltage

is given by :

( ) V = Vref − Vdet − Vofs

where

age at

V ref

the

is the voltage

DET _ O port,

aant dthVe

DET _ R port, Vdetis a volt-

ofs is the zero-input-power

offset voltage. There are three methods to calculate :

1. Vofs can be measured before each detector measure-

ment (by removing or switching off the power source

and measuring ). This method gives an error due to

temperature drift of less than 0.01dB/50°C.

2. Vofs canbemeasuredatasinglereferencetemperature.

The drift error will be less than 0.25dB.

3. Vofs can either be characterized over temperature and

stored in a lookup table, or it can be measured at two

temperatures and a linear fit used to calculate at any

temperature. This method gives an error close to the

method #1.

The RF ports are AC coupled at the RF input to the first

stage and the RF output of the final stage. No ground

wired are needed since ground connections are made

with plated through-holes to the backside of the de-

vice.

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

electrically conductive epoxy[1].

For best performance, the topside of the MMIC should be

brought up to the same height as the circuit surrounding

it. This can be accomplished by mounting a gold plate

metal shim (same length and width as the MMIC) under

the chip which is of correct thickness to make the chip

and adjacent circuit the same height. The amount of

epoxy used for the chip and/or shim attachment should

be just enough to provide a thin fillet around the bottom

perimeter of the chip or shim. The ground plain should

be free of any residue that may jeopardize electrical or

mechanical attachment.

The location of the RF bond pads is shown in Figure

12. Note that all the RF input and output ports are in a

Ground-Signal configuration.

RF connections should be kept as short as reasonable to

minimize performance degradation due to undesirable

series inductance. A single bond wire is normally suf-

ficient for signal connections, however double bonding

with 0.7 mil gold wire or use of gold mesh[2] is recom-

mended for best performance, especially near the high

end of the frequency band.

Notes:

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

2. Buckbee-Mears Corporation, St. Paul, MN, 800-262-3824



Share Link: