low temp regulation issue

3 posts / 0 new

Hi,

I am using the LNK626PG and I am seeing the voltage drop on the output around -30C. It is fine down to -20c. The voltage drops 30%. The data sheet only shows the temperature effects down to -15C. The data sheet says it is specified for -40C. Has anyone seen this before? It only happens at very light loads when the LNK626PG has low loss. As the load is increased and the losses in the LNK626PG increase, it heats up and the regulation comes back in spec.

Thanks,
Ron

Hi Ron,

Thanks for your inquiry.

It could be due to the capacitors. Is this happening only during startup and or will the drop continue indefinitely depending on the load? What is the response if you power-up at no-load?
Can you try moving (using connecting wires) the input capacitors out of the thermal chamber so the chamber temperature will not have an effect on the capacitors? Let me know what happens.

Regards,
PI-Picard

As per above, better capacitors with guaranteed ESR at low temps will likely help. ESR of electro's goes up significantly below -10 degC.