Other Parts Discussed in Thread: OPA172, OPA170, OPA171, OPA2990, TLV9062, LMV2011, OPA333, TLV171
My customer wanna to know if OPA can be used as Comparator? And Can Comparator be used as OPA? why? or Why not?
Thanks.
Regards,
Brian
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Hi Kai,
Actually the opposite of that is true. A larger differential input voltage will decrease overload recovery time and increase slew rate. Please see Figure 43 in the TLV9062 datasheet.
There is nothing wrong with using an op amp as a comparator as long as it does not have internal back to back diodes and it meets the timing requirements of your system. The transition time will be dependent on the overload recovery time of the op amp plus the time to slew from high to low (or low to high).
Thank you,
Tim Claycomb
Hi Tim,
yes, the TLV9062 shows a very nice behaviour. Unfortunately, many other OPAmps do not. Extreme recovery times can be seen in the datasheets of OPA333 and LMV2011, e.g..
And regarding the increase of supply current, please see this thread:
e2e.ti.com/.../799954
Kai
Hi Kai,
My response regarding Figure 43 in the TLV9062 datasheet was to point out that a higher differential voltage does not increase overload recovery time or decrease slew rate. A larger differential voltage decreases overload recovery time and increases slew rate.
Every op amp will have an overload recovery time whether it is used as a comparator or in normal closed loop operation.
Hi Brian,
There is nothing wrong with using an op amp as a comparator as long as it does not have internal back to back diodes and it meets the timing requirements of your system. The transition time will be dependent on the overload recovery time of the op amp plus the time to slew from high to low (or low to high).
And in your case I recommend using the OPA2990 not the TLV171 because the TLV171 has internal back to back diodes.
Thank you,
Tim Claycomb