LMR51610: Comparison with LMR51606 at low loads

Oscar Walsh

Part Number: LMR51610
Other Parts Discussed in Thread: LMR51606

My design needs to regulate ~40V down to 5V with good efficiency, and I thought the LMR516xx series looked like a good choice for this.

Initially I chose the 400kHz LMR51610, since it was most available to purchase for prototyping. However, my load will be <100mA so the LMR51606 would be fine.

Question: are there any performance differences between the LMR51610 and LMR51606 in the 10mA-100mA range? I'm assuming the LMR51610 has better switching elements (i.e. lower on-resistance?), would this translate to better efficiency?

7 months ago

0 Frank De Stasi 7 months ago

TI__Guru 61295 points

Hello

The efficiency will probably be somewhat different between those two devices in your load range.

It is hard to say if the differences would be significant in your application.

It may be best to get samples of both and test out on the EVM. You can then experiment

with different inductors and see if you can optimize the efficiency.

Thanks

0 Oscar Walsh 7 months ago in reply to Frank De Stasi

Prodigy 150 points

When you say 'different,' do you mean that the LMR51610 would likely have better efficiency than the LMR51606? Or vice versa?

0 Frank De Stasi 7 months ago in reply to Oscar Walsh

TI__Guru 61295 points

Hello

The devices are mostly the same except for the current limit settings, including the Ipeak-min which is not listed in the data sheet.

In your load range the Ipeak-min is probably the most important difference.

It may be that the higher current device will have slightly better efficiency.

You will need to check this on the bench.

Thanks

0 Oscar Walsh 7 months ago in reply to Frank De Stasi

Prodigy 150 points

OK, so under light loads, the LMR51610 may modulate the frequency (PFM) more, due to a possibly higher Ipeak-min value, potentially leading to better efficiency? Will look at acquiring some EVMs, thank you.

0 Frank De Stasi 7 months ago in reply to Oscar Walsh

TI__Guru 61295 points

Hello

Yes.

Thanks

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LMR51610: Comparison with LMR51606 at low loads