I just got LNA module from aliexpress, it is based on spf5189z chip.
It worked great, but not for long. It is died in several hours. Now it has short circuit on the output pin. And I don't understand the reason for that.
I powered it from lab power supply with 5.01 V with 0.2 A current limit settings.
It was connected to antenna through decoupling capacitor and over-voltage protection diodes (1N4148).
Output was connected to RTLSDRv3.
All equipment (PSU and PC) is grounded, include ground contact of the antenna.
I connected antenna output to BM867 in CREST mode, just to make sure that there is no high voltage pulses. It worked for a several hours and largest catched pulse is just 0.479 V.
See picture of PCB in attachment. Also I added schematic that I reversed from PCB.
Before use I replaced R1 (jumper 0 ohm) with ferrite bead (
BLM18EG601 - 600Ω @ 100 MHz / 0.35Ω @ DC).
It worked well for several tests and it's current consumption was 0.07 A.
But after next power on, I noticed that current is jumping up to 200 mA (limited by power supply).
And that's it, after that it doesn't works
![Sad :(](https://www.eevblog.com/forum/Smileys/default/xsad.gif.pagespeed.ic.L3FGyzQrjB.png)
I also found this article related to the subject:
http://pa0o-jaap.blogspot.com/2018/04/spf5189z-lna.htmlBut it's not clear what is the reason for burnout and how to avoid it?
Any idea why it happens?