I was asked to design a programmable gain amplifiers for the given specs and apparently I don't have much ideas. It would be great if someone can guide me.
Could you please provide your specifications?
Sorry for the late reply though
I would recommend that you read the following articles that touch on programmable gain amplifiers:
Precision Variable Gain Amplifiers
High Speed Variable Gain Amplifiers
A caveat to the precision VGAs is that as the configurations mostly implement a non-inverting gain, you are limited to a minimum gain of 1 or 0dB. Also, those configurations have the bandwidth changing with the gain -- I don't think you want that either. Judging from the specs that you are looking for, I think you would be more interested in the high speed VGAs, maybe an architecture similar to the AD602 would work for you. I recommend you give that device a look. You might also want to take a look at the AD8338, which has the lowest power, but will only operate at a minimum of 3V. There is a known tradeoff between bandwidth and power though, so the AD8338 does have limited bandwidth.
Just a point on your specs. You require a supply of 1.8V, but at the same time, also want an output of 2.4Vpp. Any amplifier output will be limited to its supply, so unless you use a differential output, those specs would not be possible to attain.
Would you be able to give more information regarding your application? What inputs are you expecting and how will you be using the variable gain amplifier?
Thanks a lot for your reply. I will definitely read those materials. I can use any type of opamps. As you said , an output of 2.4Vpp is required for 1.8V supply which can be achieved by fully differential or pseudo differential topology. Main goal is to get a proper simulation in ltspice for the given specs. The input is sinusoidal. If you want more information, kindly let me know. Thanks
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