MRF173 M/A-COM Technology, MRF173 Datasheet - Page 11

• Manufacturer Part Number: MRF173
• Description: RF MOSFET Power 5-175MHz 80Watts 28Volt Gain 13dB
• Manufacturer: M/A-COM Technology

Specifications of MRF173

• Configuration: Single
• Drain-source Breakdown Voltage: 65 V
• Gate-source Breakdown Voltage: 40 V
• Continuous Drain Current: 9 A
• Power Dissipation: 220 W
• Maximum Operating Temperature: + 150 C
• Package / Case: Case 211-11
• Minimum Operating Temperature: - 65 C
• Transistor Polarity: N-Channel
• Lead Free Status / Rohs Status: Details

11
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions
is considering for development. Performance is based on target specifications, simulated results,
and/or prototype measurements. Commitment to develop is not guaranteed.
PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology
Solutions has under development. Performance is based on engineering tests. Specifications are
typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available.
Commitment to produce in volume is not guaranteed.
The RF MOSFET Line
80W, 175MHz, 28V
MRF173
DESIGN CONSIDERATIONS
hancement mode field–effect transistor (FET) designed for
VHF power amplifier applications. M/A-COM RF MOSFETs
feature a vertical structure with a planar design, thus avoid-
ing the processing difficulties associated with V–groove
power FETs.
Practice, is suggested reading for those not familiar with the
construction and characteristics of FETs.
gain, low noise, simple bias systems, relative immunity from
thermal runaway, and the ability to withstand severely mis-
matched loads without suffering damage. Power output can
be varied over a wide range with a low power dc control
signal, thus facilitating manual gain control, ALC and modu-
lation.
DC BIAS
fore, does not conduct when drain voltage is applied. Drain
current flows when a positive voltage is applied to the gate.
See Figure 9 for a typical plot of drain current versus gate
voltage. RF power FETs require forward bias for optimum
performance. The value of quiescent drain current (IDQ) is
not critical for many applications. The MRF173 was charac-
terized at IDQ = 50 mA, which is the suggested minimum
The MRF173 is a RF MOSFET power N–channel en-
M/A-COM Application Note AN211A, FETs in Theory and
The major advantages of RF power FETs include high
The MRF173 is an enhancement mode FET and, there-
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
changes to the product(s) or information contained herein without notice.
value of IDQ. For special applications such as linear amplifi-
cation, IDQ may have to be selected to optimize the critical
parameters.
fore, the gate bias circuit may generally be just a simple re-
sistive divider network. Some special applications may re-
quire a more elaborate bias system.
GAIN CONTROL
rated value down to zero (negative gain) by varying the dc
gate voltage. This feature facilitates the design of manual
gain control, AGC/ALC and modulation systems.
(see Figure 8.)
AMPLIFIER DESIGN
bipolar VHF transistors are suitable for MRF173. See M/A-
COM Application Note AN721`, Impedance Matching Net-
works Applied to RF Power Transistors. The higher input
impedance of RF MOSFETs helps ease the task of broad-
band network design. Both small–signal scattering parame-
ters and large–signal impedances are provided. While the s–
parameters will not produce an exact design solution for high
power operation, they do yield a good first approximation.
This is an additional advantage of RF MOS power FETs.
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The gate is a dc open circuit and draws no current. There-
Power output of the MRF173 may be controlled from its
Impedance matching networks similar to those used with
M/A-COM Products
Released - Rev. 07.07