Hi, wonder if anybody has come across designing a gain controlled LNA with gain of -10dB to 38dB of <=1dB per step. Would appreciate your recommendation on structure and the breakdown of gain & fine tuning method.
Hi,
The DR is 48 dB, Currently no one is giving this much attenuation range.
Max available range is 31dB with 5 bit.
So hava a LNA with a gain of 44dB if 3dB is the IL for two 5 bity 1dB step attenuators.
the gain will be 44-3-3 i.e 38 and can go the attenuation to 38-31-31 i.e. -27dB.
You can have other combinations like 20dB 1 bit attenuator with cascaded 5bit step attenuator.
This part has beauty to operate in IF and RF frequency range, has mixer if you interest to use but has less gain from the requirement. So have additional LNA
Hi, kspalla, wonder if u can help to comment on structure of LNA to be used to achieve NF < 2.5dB with the attenuator added on. Currently, had tried to implement a first stage input attenuator in front of an amplifier using resistive feedback structure. The best NF obtainable is about 3dB.
Able to get NF ≈ 2.5dB at Max gain by reoptimising the LNA input matching. However, it's quite difficult to maintain the input return loss @ <8dB when the attenuation changed. Any comment?