My customer is using the OPA170. He is investigating what can happen if current is forced in or out of the op-amp output pin. Here are his comments and questions:
1. The SBOS834 –DECEMBER 2016 datasheet (OPA170-Q1) has a discussion of electrical over stress in section 7.3.3.
2. Figure 38 shows various parasitic/ESD diodes. The discussion recommends limiting input current to 10 mA. It was not clear if this referred just to functional inputs or included current into outputs as well.
3. The SBOS598A –DECEMBER 2012 datasheet (OPA170-EP) has a more limited discussion of electrical overstress but also recommends limiting current into input pins to 10 mA.
4. Both datasheets indicate in the Absolute Maximum Ratings section that Input current must be limited to +/-10mA.
5. Outputs do not have a current limitation, but are described as short circuit protected.
6. Figure 38 shows diodes that will conduct if the output is pulled outside of the power rail. Inside the power rails I assume the amplifier will oppose the stress signal.
7. I am looking at using a resistance to limit the current in or out of the op-amp output pin to less than 10 mA.
8. The stress duration will be 10’s to 100’s of microseconds rather than a short ESD pulse. Will the OPA170-EP survive?
- Adding a little more detail – he is specifically worried about 10mA going INTO the output pin and if that would damage the part.
As you can see, the customer is citing several 10mA specifications regarding potential overstress of the OPA-170-EP device.
He appears willing to ensure the application will conform to a 10mA max current, but the duration of this condition is still of concern.
Could you please look at this summary and provide a response?
Note that the OPA170-EP is discussed above. That is the preferred device. Does it have the same electrical characteristics as the OPA170? (non-EP)
Thanks.
