1GG6-8070 40–68 GHz Medium Power Amplifier

Description

The TC956 is a high–gain, medium–power mm–wave amplifier. It can be used as part of a banded solution to achieve respectable mm–wave power. Input and output ports are matched to 50 Ω.

The amplifier is biased with a single positive drain supply (VDD) and a single negative gate supply (VG1).

Applications 

The TC956 amplifier offers high gain and power to mm frequencies. It can be used in mm–wave products with high power requirements, or in conjunction with a TC958 or TC906 in a banded design. 

Biasing and Operation 

The recommended bias conditions are to connect the drains to a shared 3 V supply and connect all gate pads to a shared, adjustable negative voltage. The gate voltage is adjusted for total drain supply current of 330 mA. Drain pains 2–4 are internally connected; either multiple bonds or a single bond is acceptable. Positive gate voltage can generate drain currents as high as 700 mA, so be sure that the bonds have sufficient capacity. Likewise, all gates can be controlled with a single bond wire attached to VG4. The RF input matching circuity gives a 50 Ω DC and RF path to ground. A DC blocking capacitor should be used in the RF input transmission line. Any DC voltage applied to the RF input must be maintained below 1 V; DC voltage on the RF output can range from –7 V to +13 V. No ground wires are needed since ground connections are made with plated through–holes to the backside of the device. Reliability limits assume long–term operation into a 50 Ω match, with short–term excursions to an open circuit. Reliability will be degraded with long–term operation into an open circuit. 

Assembly Techniques 

For most applications, we recommend solder die attach. Reliability goals are modeled using solder attach to an infinite heat sink at 85 °C ambient. Epoxy attach requires 69 °C ambient. It is recommended that the RF input and output connectors be made using 500 lines per inch, or equivalent gold wire mesh. The RF connections should be kept as short as possible to minimize inductance. The DC bias supply wires can be 0.7 mil diameter gold. MMIC ESD precautions, handling considerations, and die attach and bonding methods are critical factors in successful GaAs MMIC performance and reliability.