LM317HV: Operating Temperature only goes down to 0C?

Hello,

Yes, this was very common with 20+ year-old devices. Not all were characterized below 0C, especially if they were originally intended for consumer applications. In reality, there's a good chance this device continues to operate as expected below 0C. However, without the characterization, it's difficult to say what kind of shifts in performance are expected. 

If you can give me your conversion requirements, I can see if there's another device that fits the bill. 

~ Aaron

Thanks Aaron!

My application is for a 48VDC Aerial Work Platform Lift.

The operating environment requirement is -40C to +85C. The system voltage is 48VDC nominal, 53VDC maximum.

I am only needing 30mA plus a little safety margin to power a 9-30VDC CAN controlled relay made by Wurth Electronics.

We want to regulate to 24VDC to minimize the voltage drop and heat:

https://www.we-online.com/files/pdf1/we-ics-datasheet-iccs-can-micro.pdf

Thanks for looking into a viable solution for me!

Marc

Aaron,

Also trying to stay analog here, we'd rather not step up to a DC/DC because of EMI and cost concerns.

Thanks! Marc

Hey Marc,

The best option with operation down to -40C is TPS7A4001DGNR. It can do the conversion from 53V --> 24V at 30mA but may run a little hot given the thermal resistance. That can be improved by using more Cu on your layout to bring down the effective RthetaJA number from 66.7C/W to ~45C/W. Alternatively, you can use a TPS7A4001 to regulate an intermediate rail like 36V and then follow it up with another TPS7A4001 (or TPS7A4101) to go from 30V --> 24V. This would spread the heat across two devices. 

~ Aaron