>But the output of the amplifier breaks after a short worktime
Does the operation resume after power turn off or is it a fatal fail?
It looks like a thermal issue.
The PCB layout should provide thermal pad with thermal vias. The device must be soldered to thermal pad. Vias with 1/2 or more Cu plating. Bottom layer should have 1..2 oz Cu plating.
Let me provide some estimations for the test board from NXP. It has 10mils thickness, 1/1 oz copper foil and ~0.7oz is added by plating, x14 thermal vias, 8mils diameter, 0.7 oz plating.
Second stage junction-to-case thermal resistance 26'C/W
Estimated thermal resistance of vias 1/14 * 36.1'C/W = 2.6'C/W.
Estimated 1.6x1.6 mm pad to ambient thermal resistance of 1.7 oz Cu plate 28'C/W.
-------------------------------------------------------------------
Estimated junction to ambient thermal resistance 26+2.6+28 = 56.6'C/W
Estimated junction temperature rise @Po=34dB: dT = 2W*56.6'C/W = 113'C
So, the board can be used without additional heat sink up to Ta[max] = 175'C[Tj max] - 113'C[dT] = 62'C
The result would be different if a design has different thermal via parameters, different Cu layer and board thickness.
The last item is the board-to-ambient thermal resistance. It can be minimized down to 3..6'C/W if the board is attached to a heat sink or thick metal plate.
>Could you send a working evaluation board
The most recommended procedure to obtain test board (fully assembled or not populated PCB) would be contact our authorized distributor (Richardson RFPD, mail: rfpdsales@arrow.com). Please discuss your needs with their FAE or Sales Person and ask them for placing order for this test fixture board at NXP.
You might have problem to get the board in Russia. My suggestion is to contact local distributor Simmetron. They have dedicated persons to work with NXP.
Please, if you need further board bring up assistance then create a ticket to NXP support.
Have a great day,
Pavel
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------
