MHW720A2 Motorola, MHW720A2 Datasheet - Page 2

• Manufacturer Part Number: MHW720A2
• Description: UHF Power Amplifiers
• Manufacturer: Motorola

Nominal Operation
conditions of Vs 1 (Pin 5) and V s2 (Pin 3) equal to 12.5 Vdc
and with output power equaling 20 watts. With these condi-
tions, maximum current density on any device is 1.5 x 10 5
A/cm 2 and maximum die temperature with 100 base plate
temperature is 165 . While the modules are designed to
have excess gain margin with ruggedness, operation of
these units outside the limits of published specifications is
not recommended unless prior communications regarding in-
tended use has been made with the factory representative.
Gain Control
The recommended method of power output control, as
shown in Figure 3, is to fix V s1 and V s2 at 12.5 Vdc and vary
the input RF drive level at Pin 7.
ited to 20 watts.
Decoupling
size limitation, the external decoupling network requires
careful consideration. Both Pins 3 and 5 are internally by-
MHW720A1 MHW720A2
2
All electrical specifications are based on the nominal
This module is designed for wide range P out level control.
In all applications, the module output power should be lim-
Due to the high gain of the three stages and the module
10 dB
NOTE: No Internal D.C. blocking on input pin.
Generator
Signal
MICROLAB/ FXR AD 10N
Pin 7
Z1
Pin 6
L1
V s1
Pin 5
C1
C2
C5
Figure 1. UHF Power Amplifier Test Setup
Z1, Z2 50
L1, L2 Ferroxcube VK200–20/4B
C1, C4, C5, C6 1.0 F Tantalum 25 V
Pin 4
APPLICATIONS INFORMATION
L2
Microstripline
V s2
Pin 3
C4
C3
passed with a 0.018 F chip capacitor effective for frequen-
cies from 5 through 470 MHz. For bypassing frequencies
below 5 MHz, networks equivalent to that shown in the test
fixture schematic are recommended. Inadequate decoupling
will result in spurious outputs at certain operating frequen-
cies and certain phase angles of input and output VSWR less
than 4:1.
Load Mismatch
fixture having the identical decoupling network described in
Figure 1. Electrical conditions are V s1 and V s2 equal 15.5 V,
load VSWR infinite, and output power equal to 30 watts.
Mounting Considerations
sink, use standard 6–32 mounting screws and an adequate
quantity of silicon thermal compound (e.g., Dow Corning
340). With both mounting screws finger tight, alternately
torque down the screws to 4–6 inch pounds. The heatsink
mounting surface directly beneath the module flange should
be flat to within 0.005 inch to prevent fracturing of ceramic
substrate material. For more information on module mount-
ing, see EB–107.
C6
During final test, each module is load mismatch tested in a
To insure optimum heat transfer from the flange to heat-
C7
Pin 2
MHW720A BLOCK DIAGRAM
C2, C3 0.1 F Ceramic
MHW720A Text Fixture Schematic
C7 47 F Tantalum, 25 V
MOTOROLA RF DEVICE DATA
Pin 1
Z2
Ohm
Load
50