nrf51822 and nrf51422 with DC/DC avialability

[tim]

I would like to confirm the availability of the nrf51822 with DC/DC.

Should the nrf51822 with DC/DC be used in new designs? Will it continued to be available in 2015 and later.

I am asking this question, with regards to our battery power consumption management. I understand at 2.9V to 3.0V the DC/DC will result in a reduced power consumption compared to the LDO of .75 - .8

As result the DC/DC vs LDO

LDO "power" nrf51822 LDO Total 11mA ~12mA 23mA 20mA ~22mA 42mA

DC/DC "power" nrf51822 LDO DC/DC Total 11mA ~2mA ~8mA 22mA 20mA ~4mA ~25mA 39mA

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As a result the nrf51822 operating at 16MHz and using the bluetooth radio. The power consumption will about cpu 4.4mA, radio 7mA to 16mA, with the total ~ 11mA to 20mA

What will be the effects of bluetooth 4.1 on power consumption? We are designing for a transmission burst every 350ms

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[Stefan Birnir Sverrisson]

Hi Tim

Our current recommendation on DC/DC is described here. However, we expect the nRF51 third revision hardware to have a functional DC/DC to use with the softdevices we offer. For further information you should contact your Nordic's sales representative.

Yes, you are correct that the CPU will consume 4.4mA when executing code from flash memory, and the radio consumes 7mA-16mA. However, this is not the actual current consumption because the CPU is usually not utilized 100% and the radio is most certainly not utilized 100%. For a typical BLE application, radio is utilized with around 1% and the CPU perhaps 2%-5%. When the radio is not utilized it does not consume anything, and when the CPU is not utilized, it is put into low power mode and consumes very little. Depending on the low power mode chosen, the chip consumes 0.6uA (System Off low power mode) or 2.6uA (System On low power mode), where the CPU is in low power state.

The current consumption greatly depends on your application. If you choose short connection interval, the chip will consume more power but then you will enable increased throughput and short latency. More on current consumption is described on this thread and this thread.

[tim]

There is a typo in the DC/DC calculation nrf51822 LDO DC/DC Total 11mA ~2mA ~8mA 22mA 20mA ~4mA ~15mA 39mA