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MRF8004 Transistor Data

Key transistor data for the MRF8004 RF power transistor including key electrical parameters, pinout, package type and many other key transistor datasheet details.

The MRF8004 is described as being designed use in large signal output amplifier stages.

It is intended for use in Citizens Band communications equipment operating at frequencies up to 30 MHz.

Its high breakdown voltages allow a high percentage of 'Up-Modulation' in Am transmitters.



Key details and performance parameters for the 2N4427 transistor.


Transistor Datasheet Parameters & Data
 
Parameters Details
Transistor type NPN silicon RF power transistor
Package type TO39
VCBO max (V) 60
VCEO max (V) 30
VEBOmax (V) 3.0
IC max (A) 1 continuous
TJ Max °C 200
PTOT W 5
fT min (MHz)
COB 35pF typical 70pF max
hFE 10 min
IC for hfe 250 mA
Similar / equivalents

    Outline:



    Pinout:



Explanation of transistor parameters


Parameter Explanation
VCBO Max Maximum collector-base voltage with emitter open circuit .
VCEO Max Maximum collector-emitter voltage with base open circuit.
VEBO Max Maximum emitter-base voltage with collector open circuit.
VCEsat (included where applicable) The voltage drop across the collector-emitter when the transistor is fully saturated (acting as a closed switch).
IC Max Maximum collector current.

Parameter Explanation
TJ Maximum junction temperature.
PTOT Max Maximum device dissipation normally in free air at 25°C unless other conditions indicated.
fT Min Minimum cutoff frequency at which the current gain in a common emitter circuit falls to unity.
COB Max Maximum collector capacitane, normally measured with emitter open circuit.
hFE DC current gain for HFE at IC. [Note hfe is the small signal gain and although this may be slightly different, the transistor current gain will vary considerably from ne transistor to the next of the same type.]
PTOT Max Maximum device dissipation normally in free air at 25°C unless other conditions indicated.

These are the main transistor parameters that have been included in our list. There are others, but these help quantify the main elements of the performance of the transistor.

 



Please note, that the data given is the best estimate we can give within a tabulated summary of this nature. Parameters also vary between manufacturers. Electronics Notes cannot accept any responsibility for errors, inaccuracies, etc, although we do endevaour to ensure the data is as accurate as possible.


Notes and supplementary information

 

  •   Availability & sources

The device is available from a very limited number of stockists and electronic component distributors. Old stock may be required to obtain these, or a more modern equivalent could be used.


  •   Additional details

The MRF237 was used in many HF communications radios and in particular Citizens; Band radios where it was a low cost and easily available part.

The transistor was specified as being able to provide 3.5W power output with a power gain of 10dB and a typical efficiency of 70% at 27 MHz when using a 12.5 VDC supply.

it is worth noting that the emitter connection is on the wire closest to the tab on the package in line with normal convention - a few Motorola RF power transistors do not follow this standard.

  •   RF amplifier circuit

A basic RF amplifier circuit that could be used for the MRF8004 is given below.

Transistor RF amplifier circuit for MRF804
Transistor RF amplifier circuit for MRF 8004

The circuit was intended as a test circuit for the MRF8004 but can be used as the basis of an RF power output or driver circuit.

The values for 27 MHz test circuit can be:
    C1, C2 9.0 - 180pF VHF types
    C3, C4 5.0 - 80pF VHF types
    C5 0.02µF disc ceramic
    C6, 0.1µF disc ceramic
    L1 = 0.22µH moulded choke
    L2 = 0.68µH moulded choke
    RFC1 = 4 turns #30 enamelled wire wound on Ferrocube bead types 56-990-65/3B
    RFC2 = 26 turns #22 enamelled wire wound as two layers 13 turns each with 1/4 inch inner diameter

Ian Poole   Written by Ian Poole .
  Experienced electronics engineer and author.




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