Data Sheet

ADRF5474

APPLICATIONS INFORMATION

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Rev. 0 | 13 of 14

DIE ASSEMBLY

An assembly diagram of the ADRF5474 is shown in Figure 25.

Figure 25. Die Assembly Diagram

The ADRF5474 is designed to have the optimum RF input and

output impedance match with 3 mil × 0.5 mil gold ribbon wire and

3 mil loop height typical. The bonding diagrams are shown in

Figure 26 and Figure 27. Alternatively, using multiple wire bonds

with equivalent inductance yields similar performance. For RF rout-

ing from the device, coplanar wave guide or microstrip transmission

lines can be used. No impedance matching is required on the

transmission line pad because the device is designed to match

internally to the recommended ribbon bond. A spacing of 3 mils

from the RF transmission line to the device edge is recommended

for optimum performance.

DC pads can be connected using standard 1 mil diameter wire by

keeping the wire lengths as short as possible to minimize the para-

sitic inductance. The dc pads are large enough to accommodate

ribbon bonds, if preferred.

All bonds must be thermosonically bonded at a nominal stage

temperature of 150°C, and a minimum amount of ultrasonic energy

must be applied to achieve reliable bonds.

The device is metalized on the backside, and the ground connec-

tion can be done by attaching the device directly to the RF ground

plane using a conductive epoxy. In this case, connecting the ground

pads is optional but still recommended to ensure a solid ground

connection.

Figure 26. Bonding Diagram Top View

Figure 27. Bonding Diagram Side View

HANDLING, MOUNTING AND EPOXY DIE

ATTACH

Keep devices in ESD protective sealed bags for shipment, and

store all bare die in a dry nitrogen environment.

For manual picking, it is a common practice to use a pair of

tweezers for GaAs devices. However, for die on carrier devices, the

use of a vacuum tool is recommended to avoid any damage on the

device substrate. Handle these devices in clean environment.

To attach the die with epoxy, apply an amount of epoxy to the

mounting surface so that a thin epoxy fillet is observed around

the perimeter of the chip after it is placed into position. Set epoxy

cure temperatures per the recommendations of the manufacturer

and the maximum ratings of the device to minimize accumulated

mechanical stress after assembly.

Because both dies are attached with solder joints, users must follow

best practices for the thermomechanical design of their module

assemblies. The temperature expansion coefficient of the substrate

material must match the thermal expansion coefficient of the GaAs

and silicon (Si) die. Do not allow warpage or other mechanical

deformation on the substrate. Set the die attach process and the

epoxy cure temperatures to lower the accumulated stress after

assembly.