MRF154 Datasheet, PDF (6/7 Pages) Motorola, Inc – N-CHANNEL BROADBAND RF POWER MOSFET

CIRCUIT CONSIDERATIONS
At high power levels (500 W and up), the circuit layout be-
comes critical due to the low impedance levels and high RF
currents associated with the output matching. Some of the
components, such as capacitors and inductors must also
withstand these currents. The component losses are directly
proportional to the operating frequency. The manufacturers
specifications on capacitor ratings should be consulted on
these aspects prior to design.
Push–pull circuits are less critical in general, since the
ground referenced RF loops are practically eliminated, and
the impedance levels are higher for a given power output.
High power broadband transformers are also easier to de-
sign than comparable LC matching networks.
EQUIVALENT TRANSISTOR PARAMETER TERMINOLOGY
Collector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drain
Emitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Source
Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gate
V(BR)CES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V(BR)DSS
VCBO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VDGO
IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ID
ICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IDSS
IEBO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IGSS
VBE(on) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VGS(th)
VCE(sat) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VDS(on)
Cib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ciss
Cob . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Coss
hfe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . gfs
RCE(sat) =
VCE(sat)
IC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .rDS(on) =
VDS(on)
ID
REV 2
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