OPA549 behavious

Hello Narayan,

Here's answers to your questions:

Now if I short the load what will happen to the device.

a> Will the output fall down to 0   Yes, if you short the output to ground the load will be zero ohms and the voltage will be the ground potential, 0 V.

b> will the ES pin get activated.   The ES pin serves the function of acting as an enable/shutdown pin, or it can be used as a thermal flag. Here is what the datasheet states about its functions:

ENABLE/STATUS (E/S) PIN The Enable/Status Pin provides two unique functions: 1) output disable by forcing the pin low, and 2) thermal shutdown indication by monitoring the voltage level at the pin. Either or both of these functions can be utilized in an application.

Thermal Shutdown Status The OPA549 has thermal shutdown circuitry that protects the amplifier from damage. The thermal protection circuitry disables the output when the junction temperature reaches approximately 160°C and allows the device to cool. When the junction temperature cools to approximately 140°C, the output circuitry is automatically re-enabled. 

Is there anyway for me to monitor the output short condition ?   The OPA549 does not have a current monitor pin. However, you might be able to monitor the current though the Iset pin, or the voltage at the pin. The voltage on the Iset pin drops as the current increases as can be seen from datasheet Fig. 2. If you set the current for a particular maximum and then the output is shorted, the current should limit should engage at that level. You could monitor the voltage on the pin to detect the short-circuit current condition.

Regards, Thomas

PA - Linear Applications Engineering