EEVblog Electronics Community Forum
Electronics => RF, Microwave, Ham Radio => Topic started by: Sariel on January 20, 2024, 10:57:43 am
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Hello,
I've attempted to construct an ENR device (up to 1GHz) for measuring the Noise Figure (NF) of various Low Noise Amplifier (LNA) devices.
The circuit I designed is illustrated in the attached figure.
I've successfully built a PCB and assembled all the components.
However, I'm facing an issue where I don't observe any increase in noise when connected to the Spectrum Analyzer (SA), even with the SA preamp activated.
Initially, the C15 (capacitors between amplifiers) was absent, so I cut the trace and added it.
The Zener diode is operating at approximately 4.3mA.
Strangely, there's no noticeable increase in noise attributed to the amplifiers themselves [amplifers NF+GAIN].
I'm reaching out for some brainstorming to identify the malfunction.
It's worth noting that all LDO voltages are correct, and the amplifiers receive their 5V with the current consumption falling within the nominal range for the amplifiers.
Any insights or suggestions would be greatly appreciated.
Thank you.
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Have you checked the footprint of the MAX2650 - the pins are numbered differently to what I would expect for any package!
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Have you checked the footprint of the MAX2650 - the pins are numbered differently to what I would expect for any package!
Thanks. Good advice.
This was exactly the problem.