Thermal Management

MR_DDM

I am using this part in several locations to step down from 28 VDC.

Doing thermal calculations shows issues.I am showing a 108 Degree temperature rise from a 28 VIN to 12 VOUT at 0.41 Amps.

Is my calculations wrong?

LT3980
1st Stage
INPUT					OUTPUT
V	I	TOTAL	PWR	EFF	PWR	V	I
(vdc)	(amps)	(w)	(w)	(%)	(w)	(vdc)	(amps)
28.00	0.22	6.21	3.00	0.80	2.40	12.00	0.20
28.00	0.22	6.21	3.21	0.80	2.57	12.00	0.21
			6.21	TOTAL	4.97		0.41

P_Thermal	°C/W	TOTAL
4.97	45	223.65

Thans

David

over 4 years ago

0 MR_DDM over 4 years ago

Prodigy 60 points

Is there a better device for this ?

0 LeonardEllis over 4 years ago

TI__Guru 71526 points

Hello David,

LT3980 is not a Texas Instruments device, we cannot comment on this design.

Are you wanting a replacement design using a TI device for this 28V to 12V power supply? If so, I encourage you to use a fantastic power supply design tool, WEBENCH: https://www.ti.com/design-resources/design-tools-simulation/webench-power-designer.html . Using WEBENCH for this design, there are hundreds of designs available, and you can sort by, for example, highest efficiency. Please explore these designs and let us know which one best suits your needs.

Regards,

~Leonard

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Thermal Management