Hi Expert,
My customer is using OPA858 in optical module, but for the power sequence, they will power up Vin+ and Vin- to 2.5V reference voltage, and then power up the Vs.
based on datasheet, we will see the ESD path from Vin to Vs, like the picture shown as below, could you help to double check if there will be voltage leakage in Vs or not, and what is the voltage leakage range？
Thanks.
BR
Chi
Hello Chi,
That is correct, there will be an issue with applying input voltages before the supply rails of the device. It will cause damage to the internal ESD structure of the amplifier which will cause a short between the rails and lead to an overcurrent damage.
Amplifiers are rated to +/-0.5 (voltage diode drop) to the power supply rails. The OPA858 abs max table shown below:
Is there a reason for the specific power-up sequence? Usually, we would suggest adding additional diode protection external to the amplifier if there is concern with input voltage appearing before device power-up.
Thank you,
Sima
