current peak on the nrf51822

[Jorge]

Hi,

I wanted to know the peak current of the nRF51822 chip using the softdevice 130.

I was looking through the documentation and found on the S130_SDS_v2.0.pdf the information on page 81 that the peak current should be between 15 and 16 mA when a packet is being sent/received.

I wanted to know if I can reduce this peak current or if this cannot be changed.

My goal is to power the board using a battery size 10 (meant for hearing aids) which doesn't permit high current peaks for too many times in a small period of time.

[ovrebekk]

Hi Jorge

What is the voltage of your battery?

If you enable the DC/DC regulator you can reduce the radio peak currents by about 2-3mA, but it is more effective at the higher end of the supply range (3V or higher).

If low peak currents are critical I would strongly recommend going for an nRF52 series part. They have a much more efficient DC/DC architecture, and as you can see from the nRF52 online power profiler the peaks are significantly lower.

Best regards
Torbjørn

[ovrebekk]

Hi

If the PCB is already made you might not be able to add the DC/DC, as this requires two additional inductors in your design (for details refer to the reference schematic).

Reducing the output power will shave a couple of mA's off the TX peak current, but unfortunately the RX current is the larger one in the nRF51822 (unless you use +4dBm output power today), so the largest peak will still remain.

Best regards