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Problems with HMC753LP4E and HMC392LC4 Amplifiers

Question asked by jpalleyne27 on Sep 15, 2016
Latest reply on Nov 9, 2016 by jpalleyne27

I've posted the same problem about the HMC392LC4. We were able to remove the part and bypass that section. However, the same problem is now occurring with our HMC753LP4E LNA. This issue needs to be resolved before we spin a new PC board. Here is the issue:

For each case (and there are three cases so far: 2 with the HMC392LC4 and 1 with the HMC753LP4E), the amplifiers biased up perfectly. They were drawing the typical current shown on the datasheet. The problem is that the gain response, even though very similar in shape, was lowered by a significant amount. This has happened in all three cases so far. The HMC753 is actually part of a three stage amplifier section where the other two RF amplifiers are HMC311SC70's which are leaded parts. The order of the gain section goes: LNA - RFA - RFA . I cannot test the amplifiers individually, but because two other leadless amplifiers have been shown to cause a similar problem, I am leaning toward the LNA being the problematic amplifier in the gain section. I will attempt to isolate the LNA to test it, and update this post when I do. I've also attached the 2D footprint, the 3D footprint and the 3D footprint flipped and showing the simple body of the LNA. Hoping to hear from you soon. Thank you.

RX Gain Section Before Drop in Gain

RX Gain Section After Drop in Gain

HMC753 2D Footprint

 

HMC753 3D Footprint

HMC753 3D Footprint with simple body showing underside.

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