nrf52 pcb external power supply

[ENENER]

Hi.

I'm using nrf52 dk and planning to make PCB Custom.

I want to ask three questions about nrf52 dk.

1)

First, I downloaded nrf52 reference circuirty(Schematic CIAA WLCSP with internal LDO setup)

But, There are pins A7 and H7. Two pins are named same VDD_NRF.

I'm wondering when I use External Power Supply.

There is anything have to change in reference PCB file??

Am I have to do is only connect external power supply(1.7V to 3.6V) to A7 or H7?

2)

I know External Power Supply's voltage level is 1.7V - 3.6V.

And, I'm using ADC with internal reference voltage(0.6V) and Gain(1/6). So I know ADC Voltage Level is 0-3.6V.

I want to know if I apply External Power Supply about 1.8V, can ADC measure over 1.8V - 3.6v?? 

Or can ADC measure only 0V ~ implied power supply voltage??

3)

I want to know TRACEDATA[0~3]'s role.

Currently, I know if I want to connect my custom board to nrf52 DK, only connect to GND, VDD, SWDIO and SWDCLK.

So, can I delete TRACEDATA[0~3]?

Thankyou.

[JONATHAN LL]

Hi, 


Are you planning on making a custom PCB daughter board for the nrf52 dk? Or do you want to design your own nrf52 PCB?

I want to know TRACEDATA[0~3]'s role.

The Tracedata pins are only required if you want to do a full instruction trace during debugging, but this requires dedicated trace hardware to use (the Segger chip on the development kits are not set up for this). 

For regular debugging you only need the SWD pins (SWDIO and SWDCLK). 

Are you looking at the nrf52832 dk or the nrf52840 dk ?

Regards,
Jonathan

[ENENER]

Hi

I want to design my own nrf52 PCB.

And I'm looking at the nrf52832dk.

THANKS.

[JONATHAN LL]

Hi,

Here is the layout form the reference design, as you can see the external power is connected to both A7 and H7




And the ADC's full scale input range (0 to VDD). You can read more about the ADC reference here: https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/saadc.html?cp=4_2_0_36_7#concept_kxz_4pp_qr 

I want to know if I apply External Power Supply about 1.8V, can ADC measure over 1.8V - 3.6v?? 

No.

Or can ADC measure only 0V ~ implied power supply voltage?

Yes, only from 0 - VDD or 0 - intern ref

So you can set it to be 0 -1.8v. 

Regards,
Jonathan

[ENENER]

Thanks.

It was very helpful for me.

But I want to ask one more thing.

You said "the external power is connected to both A7 and H7".

So if I want to connect external powwer supply, Only I have to do is apply voltage A7 or H7??

Thanky for replying.

[JONATHAN LL]

ENENER said:

So if I want to connect external powwer supply, Only I have to do is apply voltage A7 or H7??

 Yes,

check the documentation here: https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/power.html?cp=4_2_0_17#concept 

In the LOD setup 

Here is the operating recommendations: 1.7V - 3.6V.


I also recommend to read the PCB guidelines. 

Regards,
Jonathan