Power and clock management

Power and clock management in nRF52840 is optimized for ultra-low power applications.

The core of the power and clock management system is the Power Management Unit (PMU) illustrated in Figure 1.

Figure 1. Power Management Unit

The user application is not required to actively control power and clock, since the PMU is able to automatically detect which resources are required by the different components in the system at any given time. The PMU will continuously optimize the system based on this information to achieve the lowest power consumption possible without user interaction.

Current consumption scenarios

As the system is being constantly tuned by the PMU, estimating the energy consumption of an application can be challenging if the designer is not able to do measurements on the hardware directly. To facilitate this process, there is a defined set of current consumption scenarios.

See Electrical specification for application scenarios showing average current drawn from the VDD supply.

Each scenario specifies a set of active operations and conditions applying to the given scenario. Table 1 shows the conditions used for a scenario unless otherwise is stated in the scenario description.

Table 1. Current consumption scenarios, common conditions
Condition Value
VDD 3 V
Temperature 25°C
CPU WFI/WFE sleep
Peripherals All idle
Clock Not running
Regulator DC/DC

Electrical specification

Current consumption: Radio

Symbol Description Min. Typ. Max. Units
IRADIO_TX0

0 dBm TX @ 1 Mb/s Bluetooth Low Energy mode, Clock = HFXO

6.4 mA
IRADIO_TX1

-40 dBm TX @ 1 Mb/s Bluetooth Low Energy mode, Clock = HFXO

mA
IRADIO_RX0

Radio RX @ 1 Mb/s Bluetooth Low Energy mode, Clock = HFXO

6.4 mA
IRADIO_RX1

Radio RX @ 2 Mb/s Bluetooth Low Energy mode, Clock = HFXO, Regulator = LDO

11 mA
IRADIO_RX2

Radio RX @ 2 Mb/s Bluetooth Low Energy mode, Clock = HFXO, Regulator = LDO

12.6 mA
IRADIO_RX2

Radio RX @ 125 kb/s Bluetooth Low Energy mode, Clock = HFXO, Regulator = LDO

10.9 mA

Current consumption: Radio protocol configurations

Symbol Description Min. Typ. Max. Units
IS0

CPU running CoreMark from Flash, Radio 0 dBm TX @ 1 Mb/s Bluetooth Low Energy mode, Clock = HFXO, Cache enabled

9.1 mA
IS1

CPU running CoreMark from Flash, Radio RX @ 1 Mb/s Bluetooth Low Energy mode, Clock = HFXO, Cache enabled

8.9 mA
IS4

CPU running CoreMark from Flash, Radio RX @ 1 Mb/s Bluetooth Low Energy mode, Clock = HFXO, Cache enabled, VDDH = 5V, REG0 out = 3V

7.5 mA

Current consumption: Ultra-low power

Symbol Description Min. Typ. Max. Units
ION_RAMOFF_EVENT

System ON, No RAM retention, Wake on any event

µA
ION_RAMON_EVENT

System ON, Full RAM retention, Wake on any event

µA
ION_RAMOFF_RTC

System ON, No RAM retention, Wake on RTC (LFCLK = LFRC, normal mode)

1.3 µA
IOFF_RAMOFF_RESET

System OFF, No RAM retention, Wake on reset

µA
IOFF_RAMOFF_GPIO

System OFF, No RAM retention, Wake on GPIO

µA
IOFF_RAMOFF_LPCOMP

System OFF, No RAM retention, Wake on LPCOMP

µA
IOFF_RAMOFF_NFC

System OFF, No RAM retention, Wake on NFC field

µA
IOFF_RAMON_RESET

System OFF, Full RAM retention, Wake on reset

µA

Current consumption: Serial interfaces

Symbol Description Min. Typ. Max. Units
ISPIM,IDLE

SPIM Idle (enabled, no ongoing data transfer)

mA
ISPIM,ACTIVE

SPIM R+W data transfer, 1 MHz SCK frequency, Clock = HFINT

mA
ISPIS,IDLE

SPIS Idle (enabled, started, no activity on CSN, CLK, MISO or MOSI)

mA
ISPIS,ACTIVE

SPIS R+W data transfer, 1 MHz SCK frequency, Clock = HFINT

mA
ITWIM,IDLE

TWIM Idle (enabled, no ongoing data transfer)

mA
ITWIM,ACTIVE

SPIM data transfer @ 400 kb/s, Clock = HFINT

mA
ITWIS,IDLE

SPIS Idle (enabled, no ongoing data transfer, PREPARETX and/or PREPARERX tasks triggered)

mA
ITWIS,ACTIVE

SPIM data transfer @ 400 kb/s, Clock = HFINT

mA

Current consumption: CPU

Symbol Description Min. Typ. Max. Units
ICPU0

CPU running from Flash, Clock = HFXO

mA
ICPU1

CPU running from RAM, Clock = HFXO

mA
ICPU2

CPU running from Flash, Clock = HFINT

mA

Documentation feedback | Developer Zone | Updated 2016-12-05