BLF578 FM CW Demo

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BLF578 FM CWDemo 790 (Input) and 828
(Output)CA-171-08

• Scott Blum
• RF Application Lab
• Cumberland, RI

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Introduction

• NXP has introduced a new powerful part to its 50V
  portfolio, the BLF578
• The customer is trying to replace 2 x BLF278 with
  one device.
• This report shows how 80 efficiency can be
  obtained at 800W.
• The part has been tested in CW mode at 43, 48,
  and 50V.
• This is a tentative tune based on a mix and
  match of an input board meant for the BLF574
  (board 790) and an output board originally meant
  for VHF (board 828).
• Other tune compromises can be made based on spec
  inputs from the customer.

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Performance Summary
CW mode 43V 200mA
The device can produce 800W of FM power at 80
efficiency and remain cool, dissipating around
200W
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Layout
Note use 25 ohm B1 for real demo
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CW Gain
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CW Efficiency
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Dissipated Power
Drop in dissipated power due to non-linear 2nd
harmonic behavior
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Files
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