MITSUBISHI RF POWER MODULE

RA 07H4452 M

RA07H4452M

MITSUBISHI ELECTRIC

23 Dec 2002

7/9

ELECTROSTATIC SENSITIVE DEVICE

OBSERVE HANDLING PRECAUTIONS

PRECAUTIONS, RECOMMENDATIONS, and APPLICATION INFORMATION:

Construction:

This module consists of an alumina substrate soldered onto a copper flange. For mechanical protection, a plastic cap

is attached with silicone. The MOSFET transistor chips are die bonded onto metal, wire bonded to the substrate, and

coated with resin. Lines on the substrate (eventually inductors), chip capacitors, and resistors form the bias and

matching circuits. Wire leads soldered onto the alumina substrate provide the DC and RF connection.

Following conditions must be avoided:

a) Bending forces on the alumina substrate (for example, by driving screws or from fast thermal changes)

b) Mechanical stress on the wire leads (for example, by first soldering then driving screws or by thermal expansion)

c) Defluxing solvents reacting with the resin coating on the MOSFET chips (for example, Trichlorethylene)

d) Frequent on/off switching that causes thermal expansion of the resin

e) ESD, surge, overvoltage in combination with load VSWR, and oscillation

ESD:

This MOSFET module is sensitive to ESD voltages down to 1000V. Appropriate ESD precautions are required.

Mounting:

Heat sink flatness must be less than 50 µm (a heat sink that is not flat or particles between module and heat sink may

cause the ceramic substrate in the module to crack by bending forces, either immediately when driving screws or later

when thermal expansion forces are added).

A thermal compound between module and heat sink is recommended for low thermal contact resistance and to reduce

the bending stress on the ceramic substrate caused by the temperature difference to the heat sink.

The module must first be screwed to the heat sink, then the leads can be soldered to the printed circuit board.

M3 screws are recommended with a tightening torque of 0.4 to 0.6 Nm.

Soldering and Defluxing:

This module is designed for manual soldering.

The leads must be soldered after the module is screwed onto the heat sink.

The soldering temperature must be lower than 260°C for a maximum of 10 seconds, or lower than 350°C for a maximum

of three seconds.

Ethyl Alcohol is recommend for removing flux. Trichlorethylene solvents must not be used (they may cause bubbles in

the coating of the transistor chips which can lift off the bond wires).

Thermal Design of the Heat Sink:

Stage

(W)

(W)

(°C/W)

(A)

(V)

1

st

0.02

1.5

4.5

0.25

2

nd

1.5

7.0

2.4

1.15

12.5

η

When mounting the module with the thermal resistance of 2.85 °C/W, the channel temperature of each stage transistor

is:

The 175°C maximum rating for the channel temperature ensures application under derated conditions.