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MRF1513NT1_08 Datasheet, PDF (13/16 Pages) Freescale Semiconductor, Inc – RF Power Field Effect Transistor | |||
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MOUNTING
The specified maximum thermal resistance of 4°C/W as-
sumes a majority of the 0.065â³ x 0.180â³ source contact on
the back side of the package is in good contact with an ap-
propriate heat sink. As with all RF power devices, the goal of
the thermal design should be to minimize the temperature at
the back side of the package. Refer to Freescale Application
Note AN4005/D, âThermal Management and Mounting Meth-
od for the PLD - 1.5 RF Power Surface Mount Packageâ for
additional information.
AMPLIFIER DESIGN
Impedance matching networks similar to those used with
bipolar transistors are suitable for this device. For examples
see Freescale Application Note AN721, âImpedance
Matching Networks Applied to RF Power Transistors.â
Large - signal impedances are provided, and will yield a good
first pass approximation.
Since RF power MOSFETs are triode devices, they are not
unilateral. This coupled with the very high gain of this device
yields a device capable of self oscillation. Stability may be
achieved by techniques such as drain loading, input shunt
resistive loading, or output to input feedback. The RF test fix-
ture implements a parallel resistor and capacitor in series
with the gate, and has a load line selected for a higher effi-
ciency, lower gain, and more stable operating region.
Two - port stability analysis with this deviceâs
S - parameters provides a useful tool for selection of loading
or feedback circuitry to assure stable operation. See Free-
scale Application Note AN215A, âRF Small - Signal Design
Using Two - Port Parametersâ for a discussion of two port
network theory and stability.
RF Device Data
Freescale Semiconductor
MRF1513NT1
13
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