| Author |
Message |
shady205
Joined: 01 Oct 2006
Posts: 153
Helped: 4
Location: India Bangalore
|
 12 May 2008 6:04 Which OPAMP topology for Switched Cap Filter |
|
|
|
Hello Friends...
Which opamp topologies is best suitable for a switched capacitor filter design.
Should i consider telescopic or Folded cascode topology(both for Fully Differential & Single ended)..?
basic specifications are gain greater than 65 dB, UGB greater than 300MHz and Phase margin about 60-65 degrees for a supply voltage of 1.8Volts
Thanks & Regards
Bhagath
|
|
| Back to top |
|
 |
jecyhale
Joined: 19 Feb 2008
Posts: 447
Helped: 46
Location: China
|
| 12 May 2008 9:06 Re: Which OPAMP topology for Switched Cap Filter |
|
|
|
I think the liearity needed will detemine which topology is suitable.
Because the Gain and UGB is the basic specifications of OPAMP which can be easy realized.
|
|
| Back to top |
|
|
shady205
Joined: 01 Oct 2006
Posts: 153
Helped: 4
Location: India Bangalore
|
| 12 May 2008 9:26 Re: Which OPAMP topology for Switched Cap Filter |
|
|
|
| Total Harmonic Distortion + noise = -81 dB
|
|
| Back to top |
|
|
tia_design
Joined: 22 Feb 2005
Posts: 102
Helped: 3
|
| 14 May 2008 5:08 Re: Which OPAMP topology for Switched Cap Filter |
|
|
|
| Folded cascode with gain boost will good enough.
|
|
| Back to top |
|
|
shady205
Joined: 01 Oct 2006
Posts: 153
Helped: 4
Location: India Bangalore
|
| 14 May 2008 11:17 Re: Which OPAMP topology for Switched Cap Filter |
|
|
|
| For 65dB i don't think gainboosting is required...it would be waste of chip area and power
|
|
| Back to top |
|
|
shady205
Joined: 01 Oct 2006
Posts: 153
Helped: 4
Location: India Bangalore
|
| 16 May 2008 7:44 Re: Which OPAMP topology for Switched Cap Filter |
|
|
|
| tia Can't we go for Folded cascode as the First stage and CS as second stage with miller compensation with zero cancellation...?
|
|
| Back to top |
|
|
