Data Sheet

HMC1082CHIP

Rev. B | Page 13 of 15

APPLICATIONS INFORMATION

The HMC1082CHIP is a GaAs, pHEMT, MMIC medium

All measurements for this device were taken using the

application circuit (see Figure 38) and were configured as

shown in the assembly diagram (see Figure 39).

RECOMMENDED BIAS SEQUENCING

The recommended bias sequence during power-up is as

follows:

1. Connect GND to RF and dc ground.

4. Increase the gate bias voltage to achieve a quiescent

5. Apply the RF signal.

The recommended bias sequence during power-down is as

follows:

1. Turn off the RF signal.

3. Decrease all drain bias voltages to 0 V.

4. Increase the gate bias voltage to 0 V.

Simplified bias pad connections to dedicated gain stages and

dependence and independence among pads are shown in

Figure 35.

mended to optimize overall performance. Unless otherwise

noted, the data shown was taken using the recommended bias

conditions. Operation of the HMC1082CHIP at different bias

conditions may provide performance that differs from what is

shown in the Typical Performance Characteristics section with

MOUNTING AND BONDING TECHNIQUES FOR

MILLIMETERWAVE GaAs MMICS

Attach the die directly to the ground plane eutectically or with

conductive epoxy (see the Handling Precautions section).

To bring the radio frequency to and from the chip,

implementing 50 Ω transmission lines using a microstrip or

coplanar waveguide on 0.127 mm (5 mil) thick alumina, thin film

substrates is recommended (see Figure 36). When using

0.254 mm (10 mil) thick alumina, it is recommended that the die

be raised to ensure that the die and substrate surfaces are coplanar.

Raise the die 0.150 mm (6 mil) to ensure that the surface of the die

is coplanar with the surface of the substrate. To accomplish this,

attach the 0.102 mm (4 mil) thick die to a 0.150 mm (6 mil) thick,

molybdenum (Mo) heat spreader (moly tab), which can then be

attached to the ground plane (see Figure 36 and Figure 37).

RF GROUND PLANE

0.102mm (0.004") THICK GaAs MMIC

WIRE BOND

0.127mm (0.005") THICK ALUMINA

THIN FILM SUBSTRATE

0.076mm

(0.003")

Figure 36. Die Without the Moly Tab

RF GROUND PLANE

0.102mm (0.004") THICK GaAs MMIC

WIRE BOND

0.254mm (0.010") THICK ALUMINA

THIN FILM SUBSTRATE

0.150mm

(0.006") THICK

MOLY TAB

0.076mm

(0.003")

Figure 37. Die With the Moly Tab

Place microstrip substrates as close to the die as possible to

minimize bond wire length. Typical die to substrate spacing is

0.076 mm to 0.152 mm (3 mil to 6 mil).

Handling Precautions

To avoid permanent damage, follow these storage, cleanliness,

static sensitivity, transient, and general handling precautions:

•

Place all bare die in either waffle or gel-based ESD

protective containers and then seal the die in an ESD

protective bag for shipment. After the sealed ESD

protective bag is opened, store all die in a dry nitrogen

environment.

•

Handle the chips in a clean environment. Do not attempt

to clean the chip using liquid cleaning systems.

•

Follow ESD precautions to protect against ESD strikes.

•

While bias is applied, suppress instrument and bias supply

transients. Use shielded signal and bias cables to minimize

inductive pickup.

•

Handle the chip along the edges with a vacuum collet or

with a sharp pair of bent tweezers. The surface of the chip

may have fragile air bridges and must not be touched with

a vacuum collet, tweezers, or fingers.