airboss
Member level 3
Hi,
I'm designing an op amp. Here's the spec.
GBW = 1G
power: <20mw, vin_cm =0.9v, input swing: 0.5v p-p, output swing: 1v p-p
I used folded cascode as my 1st stage and CS as the 2nd.
************
Overall AC response without loading cap
DC gain: 48.7dB
GBW: 5.53G
PM: 0
Overall AC response with 1pF loading cap and 10pF compensation cap
DC gain: 48.7
GBW: 726.2 M
PM: 6.2
(Even if I place a 20uF compensation cap, the PM is only 16)
Individual performance before combination.
folded cascode: DC gain=27.95dB, GBW=2.92G, PM=71.4
CS : DC gain=26.78dB, GBW=12.27G, PM=85.1
Please give me some suggestion. Thanks in advance.
I'm designing an op amp. Here's the spec.
GBW = 1G
power: <20mw, vin_cm =0.9v, input swing: 0.5v p-p, output swing: 1v p-p
I used folded cascode as my 1st stage and CS as the 2nd.
************
Overall AC response without loading cap
DC gain: 48.7dB
GBW: 5.53G
PM: 0
Overall AC response with 1pF loading cap and 10pF compensation cap
DC gain: 48.7
GBW: 726.2 M
PM: 6.2
(Even if I place a 20uF compensation cap, the PM is only 16)
Individual performance before combination.
folded cascode: DC gain=27.95dB, GBW=2.92G, PM=71.4
CS : DC gain=26.78dB, GBW=12.27G, PM=85.1
Please give me some suggestion. Thanks in advance.