Regulator specifications, High voltage mode

[dev_electronic]

Dear Nordic Team,

I want to use the High voltage mode wih all DCD Regulators enabled. On VDD I have connected a Serial Flash with a max current consumption of 20mA. In the Chapter "4.7.5.2 Regulator specifications, VREGH stage" there is a max External current draw of 7mA stated (Assumes worst-case power consumption from both cores). If I set the cores to a low power mode during the Flash operations, is that applicable?

What is the max current of the regulator if both regulators are in sleep mode?

[Hung Bui]

Hi Harald, 

I would assume you still need the application core to be active to handle the communication with the serial flash. So it would draw at least 3.3mA compare to worst case 8.0mA (4.7mA lower than worst case).
The radio on nRF5340 can consume up to 5.1mA  and the netcore CPU (which can be turned off if you don't plan to do radio activity) is 2.6mA wost case. 

In total it's 4.7mA + 5.1 + 2.6 = 12.4 mA extra when you put them to sleep/low power. So you are right at the limit if you want 20mA output. 

I would suggest to try to do some test by using a simple resistor drawing 20mA or try with 22mA and see if you have voltage drop on the VDD pin and if the app core can still operate normally. 
Which voltage your external flash run on ? 

Disclaimer: This is not something we covered in our spec, so I can't provide any guarantee that drawing 20mA would work. 

[dev_electronic]

Hi Hung,

thanks a lot. That is a good approach to verify if the circuit can handle it. The flash runs on 3.3V.