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I am using DAC8718SRGZT for one of the industrial application for the analog outputs i have used OPA1664 in voltage follower configuration. Op-amp output is connected to E/P converters. Now i want to protect the opamp output from accidental connection to power supply (24V). Is there any recommendation?
Hi Dinesh,
I recommend that you implement some transient voltage suppression as well as some attenuation schemes.
You could look at this reference design for some examples of this scheme:
https://www.ti.com/lit/ug/sbau229/sbau229.pdf
This device has protection to help reduce the risk during accidental miss-wiring.
Thanks!
Paul
Hi,
Can you please share your current schematics, so that we can have a look at and suggest protection schemes for the same?
As Paul mentioned, device has protection to help reduce the risk during accidental miss-wiring and also the tech/app note shared by Paul is a great place to start with and implement the same.
Regards,
AK
Above is the schematic. This is done as per some recommendation by out customer.
Below was the schematic earlier:
With TPSMF4L33A diodes installed, devie was drawing more currnet and supply regulators getting heated.
After removing these diodes, board was working properly.
I used op-amp because output is driving E-P converter, for which input current is higner than output of DAC8718.
Thanks,
Dinesh KS
Hi,
Both protection schemes you have outlined above should work, I don't see any issues.
I am still thinking why the TPSMF4L33A caused heating up of your regulator. Did you change the diodes with new set of devices to check if any of the component was faulty?
Regards,
AK
Hi AK,
We tried by installing new TPSMF4L33A, but still that problem occurred. So we removed TPSMF4L33A from the board.
Here is the circuit i updated as per recommendation by paul and you:
Also VOUT_1 is connected to E/P converter "ITV0030-3M" (https://www.smcpneumatics.com/pdfs/ITV.pdf), through terminal block "1803659" (https://www.phoenixcontact.com/online/portal/us/?uri=pxc-oc-itemdetail:pid=1803659&library=usen&pcck=P-11-02-11&tab=1&selectedCategory=ALL).
Please guide me if anything is not correct.
Thanks,
Dinesh KS
Hi,
Thank you for giving the valuable suggestions and references.
Regards,
Dinesh KS