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AFT09MS015N - NO OUTPUT

Question asked by Shashank Mutha on Jul 2, 2017

Hello,
       We are using the aft09ms015n and built a board as per the  reference design provided for operation between 350-520 MHz.
The setup:
1) Input frequency 433MHz
2) Input power level: 10dBm
3) Vds = 12.5V
4) Vg = start from 0 to 3.1V

5) 50dB attenuator (30W) on the output side.

 

The problem: We don't see any output at all.

 

Gate and drain voltages were confirmed at the device's pins.
Startup process: Vds was set to 12.5V and gate voltage gradually increased from 0V. The current drawn at different gate voltages is as follows:
Vgate Ids (A)
2.5      0.004
2.6      0.014
2.7      0.039
2.8      0.099
2.9      0.304
3.0      0.600 (keeps increasing) 0.655 and up
3.1      1.035 and keeps increasing

From 2.9V onwards the current keeps increasing continuously (could it be a thermal run-away). The PCB is mounted on an aluminum plate for dissipating the heat. 

We were advised that the device could be oscillating but we checked the spectrum all the way till 20GHz but there is no sign of oscillation. 

Thank you for helping us out,

Regards,

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