NRF5340 Power Consumption details

RE: NRF5340 Power Consumption details

Stian Røed Hafskjold — Thu, 13 Jan 2022 10:51:43 GMT

I should also add that in most applications the CPU (3.3mA) is mostly in idle (< 2uA). It only wakes up to do its tasks for a few µs at a time, and then goes back to idle. Of course unless you are running some very CPU intensive algorithms.

RE: NRF5340 Power Consumption details

Stian Røed Hafskjold — Wed, 12 Jan 2022 15:17:41 GMT

Since the SPIM is using DMA the CPU is not involved during the transaction. But if the application CPU is doing something else at the same time, you will have to add the CPU current as well, to get the potential peak current. But again, the IAppcpu5 contains parts of the clock tree that is distributed to both the CPU and the SPIM, so it should be lower than 935 uA + 3.3mA. Also the current consumption of the CPU depends on what it is doing, how many wait states, how often there is a DMA write/read, etc.

RE: NRF5340 Power Consumption details

sredaley — Wed, 12 Jan 2022 14:11:13 GMT

Does this mean that the total consumption for running a SPIM Transfer at 2Mbps is 935 uA inclusive of the Application core?

Or is current consumption of a SPIM Transfer at 2Mbps 935 uA + IAppcpu5 3.3mA for example..

RE: NRF5340 Power Consumption details

Stian Røed Hafskjold — Wed, 12 Jan 2022 14:05:53 GMT

Hi, the master peripherals do not consume any extra current when they are enabled but idle. It's only the slave peripherals that are waiting from an interrupt on the chip select pin that will consume extra current in idle.

In the nRF53 PS, under current consumption -> electrical specification, the numbers are reported as single compounded numbers, including the HF clock and the DMA current, which will be a significant part of the total current consumption. The HF clock and DMA currents do not duplicate when more than one peripheral is running, so you can't add up the reported run currents for the TWIM and SPIM. The run current for one peripheral alone is in the < 100 uA range.