deveshkm
Member level 4
Hi,
I am designing a Programmable gain amplifier using DDA
DDA has NMOS input diff pairs
PGA uses variable feedback resistance (3k,9k,12k)
DDA is followed by single-ended OTA
Single-ended OTA is designed by using differential pair with current mirror load.
The open loop gain of SE - OTA is 40dB.
I have used it with unity-feedback.
In order to obtain optimal phase margin, I have utilized Miller compensation.
Is this a good option or should I use a different amplifier as buffer?
In open loop, DDA+buffer has a PM of 56 degrees.
Miller compensation is done using resistor 12.5k ohm and capacitor 2.2pF.
Is it possible to use any other OTA as buffer?
I am designing a Programmable gain amplifier using DDA
DDA has NMOS input diff pairs
PGA uses variable feedback resistance (3k,9k,12k)
DDA is followed by single-ended OTA
Single-ended OTA is designed by using differential pair with current mirror load.
The open loop gain of SE - OTA is 40dB.
I have used it with unity-feedback.
In order to obtain optimal phase margin, I have utilized Miller compensation.
Is this a good option or should I use a different amplifier as buffer?
In open loop, DDA+buffer has a PM of 56 degrees.
Miller compensation is done using resistor 12.5k ohm and capacitor 2.2pF.
Is it possible to use any other OTA as buffer?