I guess when you’re battery operated, every uA is sacred. I’ve just done some current measurements on my 50 sensor bus. In all these pics, Blue is the 1wire bus, and Yellow/Green are the dual-range current probe, and they’re all basically different zoom levels of the same thing.
The big picture. With 50 devices on the bus, I can’t do broadcast conversions; instead I always have one ds18b20 converting and when it’s done, start the next one. In this pic each conversion takes about 600 msecs (12-bit) and then there’s some 1wire chatter to fetch the result and start the next one converting.
Zoomed in on one of those long conversion stretches. The average current being drawn during the conversion is 647uA (cf. datasheet at a typical active current of 1mA). Those 10 msecs Blue pulses are me probing the bus to see if it’s done yet. With 50 devices to get through I need to move on as soon as possible rather than wait a set time - particularly useful for cloned devices which are about 10x faster.
Zoomed in on an end-of-conversion. My Blue are-you-done-yet probe was 2 msecs too early, so had to wait another whole 8 msecs for the next one. During that 8 msecs of bus idle time you can see the current drops away to practically 0… even with 50 devices on the bus. Then the next bus probe sees the conversion is complete and starts comms - which causes lots of short sharp current spikes on the bus edges - peaking at 10.35mA, but all of them very short lived.
Zoomed in on the quiet time. I really need a bigger shunt, but according to that noise the average draw during the idle time is 16.9uA, or about 340nA per sensor (cf. 750nA from the datasheet).