| Author |
Message |
gunpla
Joined: 16 Mar 2006
Posts: 15
|
 04 Mar 2007 7:48 How to measure slew rate(SR) for fully differential OTA? |
|
|
|
|
Dear All:
i would like to measure the slew rate(SR) and slew rate output(SRO)
for fully differential OTA.
i search the three method of measured evnironment
if these method mistake
can someone tell me measured scheme or upload the schematic?
thanks!
|
|
| Back to top |
|
 |
MSSN
Joined: 08 Mar 2006
Posts: 232
Helped: 26
|
04 Mar 2007 8:39 Re: How to measure slew rate(SR) for fully differential OTA? |
|
|
|
|
| I think the second method can be used but u have to add ur load capacitance at the output of the OTA
|
|
| Back to top |
|
|
melc
Joined: 08 Apr 2005
Posts: 394
Helped: 45
|
04 Mar 2007 9:24 Re: How to measure slew rate(SR) for fully differential OTA? |
|
|
|
|
The third methode is wrong because of the input RC delay and integrative configuration.
The first and the second methode does not measure the real slew rate of the fully differential output, the slew rate will be different for inverting input (image 2) versus noninverting input configuration (image 1).
However any of the measuremet schemes 1 or 2 will gave you an approximative value of the slew rate. If you need a precise one, use a fully differential generator and measure the differential output value with a dual channel scope.
|
|
| Back to top |
|
|
Google
AdSense
|
04 Mar 2007 9:24 Ads |
|
|
|
|
|
|
| Back to top |
|
|
gingerjxb
Joined: 26 Feb 2007
Posts: 57
|
04 Mar 2007 9:28 Re: How to measure slew rate(SR) for fully differential OTA? |
|
|
|
|
| maybe these methods are all feasible, i don't know. hope intelligent answers
|
|
| Back to top |
|
|
seanyang
Joined: 12 Dec 2006
Posts: 28
Helped: 5
|
05 Mar 2007 3:04 Re: How to measure slew rate(SR) for fully differential OTA? |
|
|
|
|
Using the first method and add the Rload & Cload.
Give it a VPLUS voltage (from 0~vdd).
And you will see the output will follow the input with a slop.
The 10% to 90% slop is you SR.[/img]
|
|
| Back to top |
|
|
jonashat
Joined: 07 Sep 2005
Posts: 75
Helped: 5
|
05 Mar 2007 3:19 How to measure slew rate(SR) for fully differential OTA? |
|
|
|
|
I'd go with the second, but make sure you very large resistors so that it doesn't affect the output current.
First is also fine, as seanyang described.
|
|
| Back to top |
|
|
