From IC Revision 1 to 2
While there are quite a few changes available for review in the nRF52840
documentation, there is update that is particularly important for many users out there, including a large amount of our own customers. The update I am talking about is about the power supply.
First things first – if you’re interested in reading the whole documentation for Nordic Semiconductor’s nRF52840, then look no further than their Infocenter.
As you can see in the picture below, there’s a lot of information about LDO and DC/DC regulators. That is exactly the main topic of today’s post.
On nRF52840 version C, when changing from 5.5V to 3.3V, you had to use LDO mode in order for the chip to function properly. In the new chip version 2, you won’t have to change to LDO mode as you can directly use REG0 DC to DC.
I will let the Infocenter documentation speak for how it works in detail as quoted below:
The system contains two main supply regulator stages, REG0 and REG1.
Each regulator stage has the following regulator type options:
Low-dropout regulator (LDO)
Buck regulator (DC/DC)
In normal voltage mode, only the REG1 regulator stage is used and the REG0 stage is automatically disabled. In high voltage mode, both regulator stages (REG0 and REG1) are used. The output voltage of REG0 can be configured in register REGOUT0. This output voltage is connected to VDD and is the input voltage to REG1.
By default, the LDO regulators are enabled and the DC/DC regulators are disabled. Registers DCDCEN0 and DCDCEN are used to independently enable the DC/DC regulators for the two stages (REG0 and REG1 respectively).
When a DC/DC converter is enabled, the LDO for the corresponding regulator stage will be disabled. External LC filters must be connected for each of the DC/DC regulators being used. The advantage of using a DC/DC regulator is that the overall power consumption is normally reduced as the efficiency of such a regulator is higher than that of a LDO. The efficiency benefit of using a DC/DC regulator becomes particularly prominent when the regulator voltage drop (difference between input and output voltage) is high. The efficiency of internal regulators vary with the supply voltage and the current drawn from the regulators.
Note: Do not enable DC/DC regulator without an external LC filter being connected as this will inhibit device operation, including debug access, until an LC filter is connected.
We hope you get a better understanding about the update from nRF52840 Revision 1 to 2 and its power supply.
Raytac now has started supply module demo board, MDBT50Q-DB, build by nRF52840 v2 SoC.
If you would like to purchase our MDBT50Q-DB demo board (deployed module: MDBT50Q-1MV2) on it, you can get one on eBay or Verical.
We at Raytac wish you all a nice day and happy tinkering 🙂