LMV431A: LMV431A derating above 85°C

Hi Bastian,

Are you measuring the case temperature at 25C ambient temp or is the ambient temp of the device at +85C?  Based on the information you provided, the device is under the SOT-23 derating curve which is good.  The operational temperature for the LMV431A is -40C to +85C ambient. 

Ben

Hi Ben,

I measure the temperature of the device directly on the case with a small thermocouple sensor. The device is mounted on a PCB with lots of other components in a housing tested at 60°C in a thermal chamber. The themocouple sensor measures 86°C and is thermally connected to the case via thermal paste.

So I know, that the case temperature is already at 86°C, with 40mW losses  and calculated with a Rthja of 455 °C/W (this is conservative, Rthjc would be smaller)  I would have a junction temperature of ca. 105°C which would be ok, if I consider comment (2) in 7.4 of your datasheet.

But as already meantioned, the REcommended Operationg Conditions say no to anything greater 85°C for my understanding.

Bastian

Hi Bastian,

Have you looked into the TLVH431-Q1 product?  The temp range is -40C to 125C.  Also, there is the LM4041-N which has a temp range of also -40C to +125C.

Ben

Hi Ben,

Thanks for supporting with different products! If possible I would like not to change the part here. 

You say "The operational temperature for the LMV431A is -40C to +85C ambient" but these values are corresponding to a test setup described in JEDEC JESD51-2a right ? Is there a good application note available how to take the temperature values into account?

Best regards,

Bastian