Hi all,
I have got a question about the slew rate variation of OPA376-Q1. Can you tell me how OPS376-Q1 slew rate changes when temperature changes to -40degC and 125degC? Also, I would like the data of slew rate when output gain is +10 and +100.
If you have any data related to this, I'd be appreciated to get those data.
Regards,
RYO
Ryo,
The change of the OPA376-Q1 slew rate over temperature is directly related to the change of quiescent current, IQ, with temperature, SR~IQ/Cc, where Cc is internal Miller capacitance - see below. Thus, at 125C the slew rate will increase from what it is at 25C by about 8% (by a ratio of 820/760) while at -40C the slew rate will decrease by about 5% from what it is at 25C (by ratio of 725/760).
Having said that, the OPA376-Q1 typical IQ of 760uA may change lot to lot due to process variation by up +/-10% and Cc may also change by up to +/-10%, for a total of +/-20%. Thus, depending on the wafer lot, the typical slew rate at 25C may be anywhere from 1.6V/us to 2.4V/us and therefore the +8%/-5% temperature variation must be taken from OPA376-Q1 actual slew rate for a given wafer lot.
All in all, this means that across the process and temperature variations OPA376 slew rate may be as low as 1.5V/us at -40C (0.95*1.6) or as high as 2.6V/us at 125C (1.08*2.4).
Another small point to keep in mind is as the gain goes up, eventually you will bandlimit the step edge rate to never go into slew limiting, as shown here for a gain of 100X single pole limited step response.
