nrf52840 RX with DCDC is high current comsumption

[loquat]

I am developing on RAYTAC MDBT50Q-DB board.(nrf52840)

I measured current comsumption on RX mode.

with DCDC:  about 8mA

without DCDC: about 11mA

datasheet written,

DCDC RX only run current(DC/DC,3V) 1Mbps/1Mbps BLE 4.6mA
  1M RX only run current(LDO,3V) 1Mbps/1Mbps BLE 9.9mA

It'S seem that MDBT50Q-DB board's DCDC current is high.

I execute for enter DCDC,

sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE)

only.

What do I missing?

[Stian Røed Hafskjold]

8 and 11 mA seems a bit high. 1M RX only run current is the radio run current without DMA and HF clock current which is needed. Please see the current consumption scenarios instead. These numbers include all peripherals that is needed for the radio to run: http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52840.ps/_tmp/graviton/autodita/CURRENT/parameters.id_current_radio.html

I would expect the RX numbers to be closer to 6 and 10 mA for the DCDC/LDO respectively.

Can you post the code you are using to measure. And also describe your measurement setup in detail.

[loquat]

I measured current comsamption by 'examples/ble_central/ble_app_blinky_c' on SDK15.0.0
before run a program,
ldscript's memory address modified
NRF_LOG disable


Result

BLE nano2 (SoftDevice S132 V6.1.0)
w/DCDC   5mA
wo/DCDC 11mA

MDBT50Q-DB (SoftDevice S140 V6.1.0)
w/DCDC   8mA
wo/DCDC 10mA


BLE nano2 is as expected result.
But MDBT50Q-DB seem too current.

MDBT50Q-DB's Specific problem?
(Measurement method upload)

[loquat]

connect POWER to J9(Jlink) VCC and GND.

(POWER(3V) -> J9 VCC GND -> J9 GND)

[Stian Røed Hafskjold]

Seems like something is wrong with the raytac board then. Are you sure USB is not plugged in or that any other components on the board can consume current? I don't have the Raytac board here so unfortunately I can't test here. Did you remove the programming cable and power cycle the board after flashing?

[loquat]

I try to run that scan start and stop interval 10 seconds.

among scan start -> about 8mA
among scan stop  -> about 0mA(may be <1mA)

So that, may be not comsume current by other componets.

[Stian Røed Hafskjold]

With a resolution of 1mA you have 8mA RX (which can be 7.5mA), and idle current of < 1mA. This gives you an RX current of 6.5mA which is within spec.

[loquat]

OK

Thanks.