LM1117: Thermal Resistance Curves

Harsh Songara

Part Number: LM1117

Hello, I plan to use the LM1117-3.3V for my 3V3 Regulated output from a 5V input. The required current output is 0.8A (worst case scenario). I was looking at the thermal resistance curves and wanted to know by how much would the thermal resistance decrease for higher copper areas (say like 3.3inches²). The curve provides details only upto 1inches²

Thank you!

Best,

Harsh Songara

over 4 years ago

0 Kyle Van Renterghem over 4 years ago

TI__Genius 14245 points

Hey Harsh,

It levels off quite a lot as can kinda be seen in the plot. We don't have additional data beyond that point however we have an App Note which shows how the thermal dissipation (θja) can be affected by board layout and it shows that with an optimized PCB layout the θja listed in our datasheets can be reduced by 35%-55%.

https://www.ti.com/lit/an/slvae85/slvae85.pdf

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LM1117: Thermal Resistance Curves