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Comment by retSava | Hacker News Reader

At a "couple of hundred microamps" penalty, this more or less kills a wide range of potential products, ie battery-operated products like smart sensors or remote controls and the like.

One of the most important factors for a long lifetime is to minimize the static power draw, and running at 0.1--10 uA is quite common.

A common CR2032 has about 225mAh. If you can get 80% out of it, you have about 225 * 1000 * 0,80 / 24 = 7500,0 uA-days. At 10uA, you have roughly 2 years (depending on usage etc). At "a couple hundred uA", you'll have two months.

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I, too, chuckled at the "couple of hundred microamps" quote. However he refers to the high-speed clock, which is turned on only during transmit/receive, and is indeed negligible compared to the total power consumption during RF communication.

That being said, their low-frequency on-chip oscillator specs are horrendous (50ppm PER DEGREE). You can't maintain a BTLE connection or mesh node with that kind of clock, you still need a 32kHz crystal oscillator, so TI haven't "solved" the crystal oscillator problem just yet...

Indeed; they clearly haven't solved accuracy. But they've done a remarkable job of cleanliness. In particular, the close-in phase noise (e.g., at offsets from carrier < 1 KHz) these BAW-endowed parts are amazing.

With the CC26xx parts you can use a 32kHz RCOSC and get accurate enough timing for BTLE connections, so with the CC2652RB you should be able to have true "crystal-less" Bluetooth LE.

Not necessarily. The application in question is for the baseband reference frequency in a radio. If the oscillator can be powered down with the radio, and powered on during transmit, it would be a great savings.

A good callout re: low power applications, however.

Its speaking of it as 2% as well. The 2% right before it means the 200uA is relative to starting at 10mA. Your CR2032 is already not going to make it a day. That you lost about half an hour off of 22 hours doesn't mean much. I suspect this application is not useful to ultra low standby systems, but rather around RF applications of some sort that are already much hungrier for power than 10uA.

Oof, didn't notice that. The 2% penalty seems to be relative to the entire chip's power consumption with the radio on and heavy CPU activity. If you compare with the 680 uA specified typical power consumption with the radio off and CPU idle but no other power-saving features activated, that extra couple of hundred microamps seems like a much bigger deal.

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