Verification for schematic for custom Board

RE: Verification for schematic for custom Board

Martin Sivertsen — Thu, 20 Jan 2022 12:51:08 GMT

Hi Moghees,

Yes that should work fine.

I recommend reading through the documentation for the PPK II either on our Infocenter or in PDF-format (that is made from the information found on the Infocenter).

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Moghees — Wed, 19 Jan 2022 08:25:05 GMT

Thank you for the reply

So as per my understanding if I connect PPK II with a laptop and connect VOUT, GND pins of PPK II with battery pins on my custom board, then I can calculate the power consumption of my device using PPK II. Please find attached the block diagram that I made to show the connection between PPK II and the custom board

I need to confirm that we will be able to measure the power consumption of our custom board using PPK II because we have to import PPK II device

Regards,

Moghees Bin Zahid

RE: Verification for schematic for custom Board

Martin Sivertsen — Tue, 18 Jan 2022 14:39:24 GMT

Hi Moghees,

Yes you can use the PPK II to measure the total current consumption of your device.

You could solder pin headers in the holes where the battery connector is supposed to be and connect your DUT (Device Under Test) to the PPK using jumper wires, and measure current in source meter mode. Note that this mode has a maximum admissible current of 600 mA, ampere meter mode lets you draw up to 1 A of continuous current, but requires a different connection scheme.

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Moghees — Tue, 18 Jan 2022 04:42:45 GMT

Hi Martin,
We want to calculate the power consumption of our Custom Board
I want to ask if we can measure custom board power consumption using Power Profiler Kit II?
If yes what are the connections we need to make so that we can get ower consumption of our custom board?

Regards,

Moghees

RE: Verification for schematic for custom Board

Moghees — Mon, 03 Jan 2022 16:02:23 GMT

Thankyou for the reply

RE: Verification for schematic for custom Board

Martin Sivertsen — Mon, 03 Jan 2022 15:38:13 GMT

Hi Moghees,

Apologies for the delay, but I am back from holiday now and have looked at your design mainly with regards to the antenna interference question.

All looks to be in order there, the placement of L2, C1, C2, C17, C18 and C4 will have no impact on the antenna.

I would remove the small sliver of copper on the top and bottom layer marked with green.

A lot of vias are placed in a way that creates a very small clearance gap (marked with red arrows), please move these so the clearance conforms with the clearance that your PCB manufacturer can produce within a standard process. The provider NCAB for example has a minimum of 0.075 mm gap for a standard process (and 0.05 mm for an advanced process which costs more). Check your PCB manufacturer to see what clearance tolerances they have:

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Martin Sivertsen — Thu, 16 Dec 2021 21:35:49 GMT

Hi Moghees,

I have a bit of a workload at the moment.

I have my last day of work tomorrow before two weeks of holiday, I'll try to look at your board if I can, but worst case it'll have to wait until after new years.

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Moghees — Wed, 15 Dec 2021 12:43:25 GMT

Hi Martin,
I have finalized the PCB Design. Kindly check for antenna interference. Following components that are linked with antenna or nRF52840 SoC have been changed. Kindly see if they are correct and will not cause any problem to the antenna:

1. L2 (attach with pin DCC)
2. C1, C2, C17, C18 (with crystal X1 and X2)

3. C4 (on RF Antenna)

Note: I have updated the PCB design and Please find attached zip fine containing hardware, BOM, Gerber, Pick and Place files
devzone.nordicsemi.com/.../LL_5F00_v2.0.1.zip

Regards,

Moghees Bin Zahid

RE: Verification for schematic for custom Board

Moghees — Tue, 14 Dec 2021 12:12:51 GMT

[quote userid="13081" url="~/f/nordic-q-a/79173/verification-for-schematic-for-custom-board/343311#343311"]You want me to check if there is any trace on version 2 of your PCB design that can cause interference with the antenna?[/quote]

Yes

[quote userid="13081" url="~/f/nordic-q-a/79173/verification-for-schematic-for-custom-board/343311#343311"]I'll have to take a look at the layout files to see that, so you can upload them whenever you feel ready.[/quote]

Let me finalize the design. I have to change a few components due to the unavailability of them with the PCB manufacturer. Once I get it finalized on my end I will share it with you

Regards,

Moghees Bin Zahid

RE: Verification for schematic for custom Board

Martin Sivertsen — Tue, 14 Dec 2021 07:52:24 GMT

Hello Moghees,

I'm not sure I understand the request.

You want me to check if there is any trace on version 2 of your PCB design that can cause interference with the antenna?

I'll have to take a look at the layout files to see that, so you can upload them whenever you feel ready.

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Moghees — Tue, 14 Dec 2021 07:30:25 GMT

Hi Martin,

I want to ask If it is possible for you to kindly check out if there is any trace on Version 2 of PCB design that can cause problem/Interference to onboard BLE antenna for nRF52840 SoC, the rest of the things I will look on my own?

If yes kindly tell me I will upload PCB files

Regards,

Moghees Bin Zahid

RE: Verification for schematic for custom Board

Martin Sivertsen — Mon, 13 Dec 2021 09:29:11 GMT

You're welcome!

RE: Verification for schematic for custom Board

Moghees — Mon, 13 Dec 2021 09:27:19 GMT

Thank you for the great support

RE: Verification for schematic for custom Board

Martin Sivertsen — Mon, 13 Dec 2021 09:21:25 GMT

Hi Moghees,

It seems you've understood correct to me.

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Moghees — Mon, 13 Dec 2021 06:28:31 GMT

Thank you for the reply. I have added a load switch to control battery monitoring and I will remove the Zener diode and recalculate values of R1 and R3

I have one question regarding the ADC channel of nRF52840

I was reading nRF52840 SoC documentation. I found the following table that shows the values of R1 for a particular sampling time

I have chosen a sampling time of 40us for which max resistance could be 800K, I am using value 787K for R1 and will calculate the value of R3

I want to ask if my understanding regarding ADC as mentioned above is correct?

Regards,
Moghees Bin Zahid

RE: Verification for schematic for custom Board

Martin Sivertsen — Sun, 12 Dec 2021 19:57:50 GMT

Hello Moghees,

[quote user="Moghees"]SPDT will be only needed to connect and disconnect batteries? [/quote]

Yes.

Regarding the battery measurement: Let's assume that the single cell alkaline batteries have a maximum voltage when fully charged of 1.8 V, four of them gives a total voltage of 7.2 V. Choosing R1 = 1M ohm, and R3 = 500k ohm on a standard voltage divider gives us a Vout of 2.4 V which is within range. Having such high values for R1 and R3 also has the added benefit of reducing current leakage. If you add a MOSFET in series and control the gate with a GPIO you can even turn the battery measurement on and off at will.

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Moghees — Sat, 11 Dec 2021 05:49:44 GMT

Thank you for the detailed reply Martin. Sorry for causing you inconvenience.

[quote userid="13081" url="~/f/nordic-q-a/79173/verification-for-schematic-for-custom-board/342998#342998"]You don't need ferrite beads for the battery, but a SPDT switch would be a good feature to be able to disconnect power and power cycle the device in a simple way.[/quote]

I will remove ferrite beads but just to be clear I have a different connection for the battery and USB. SPDT will be only needed to connect and disconnect batteries?

[quote userid="13081" url="~/f/nordic-q-a/79173/verification-for-schematic-for-custom-board/342998#342998"]It would likely be easier (and cheaper) to just adjust the value of resistors R1 and R3 to get a Vout within the correct range[/quote]

The problem is that 4XAA cells in series should theoretically give 6V but practically some cells can have voltage above than 1.5V which will result in voltage greater than 6, which will result in voltage across R3 greater than 3V and nRF52840 SoC can be damaged. One solution is that I use Zener other is that I assume the max voltage from the batteries can be 8V and calculate the value of R3 in that case voltage across R3 will not exceed 3V, So Should I use the 2nd approach or Zener is better?

Thank you so much for taking a timeout for this

Regards,
Moghees Bin Zahid

RE: Verification for schematic for custom Board

Martin Sivertsen — Fri, 10 Dec 2021 22:11:02 GMT

Hi Moghees,

Apologies for the delay.

[quote user="Moghees"]Are GPIOs mentioned above fine or should I use other ones?[/quote]

Yes, they are fine.

[quote user="Moghees"]I am using the same Ferrit Bead for Battery as of USB-C, is it ok?[/quote]

You don't need ferrite beads for the battery, but a SPDT switch would be a good feature to be able to disconnect power and power cycle the device in a simple way.

[quote user="Moghees"]As I am operating nRF52840 SoC on 3V, the ADC channel can only take a max of 3V as input, for that purpose I am using Zener Diode can you verify Battery Monitoring Circuit? [/quote]

It would likely be easier (and cheaper) to just adjust the value of resistors R1 and R3 to get a Vout within the correct range.

[quote user="Moghees"]Now we have 2 power sources i.e, 5V from USB-C and 6V from the battery, for source selection I am using Schottky Barrier Diode Oring Scheme, can you verify its circuit?[/quote]

It looks fine to me.

[quote user="Moghees"]I am using Linear voltage regulator HT7830 for getting 3V to run nRF52840 SoC.[/quote]

It looks fine to me.

[quote user="Moghees"]I am exposing pins to connect the micro and Reed switch, is it ok?[/quote]

Yes.

[quote user="Moghees"]Do you recommend adding capacitors with motor driver IC?[/quote]

Yes, the datasheet of the motor driver IC usually has a recommended circuit or application circuit with recommended values. But a tantalum (polarized) capacitor of 10 uF and a ceramic one of 100 nF is probably not a bad idea.

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Martin Sivertsen — Tue, 07 Dec 2021 10:06:12 GMT

Hello Moghees,

I have a significant work load at the moment, but I'll get to your board soon, you'll hear from me tomorrow at the latest.

At the same time I have to mention that we rarely do full schematic reviews, we just don't have the resources for it, we focus on the nRF-device and RF front end (matching circuitry and antenna layout).
If the board is fairly simple we can sometimes look at the rest as a courtesy, but it just becomes too time consuming to do it for every customer design.

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Moghees — Mon, 06 Dec 2021 12:21:33 GMT

Hi Martin,

How are you?

After successful testing of version 1 of the board, we are going to design version 2. Requirements are:

It should be battery operated, we will be using pair of 4xAA cells in series
It should be capable of Battery Monitoring (using pin P0.29/AIN5)
Interface for motor control (using pin P0.20 and P0.22)
Interface to attach Reed switch (using pin P0.13)
Interface to attach 2 micro Switch (using in P0.24 and P0.25)

Can you kindly verify Schematics and answer my following questions:

Are GPIOs mentioned above fine or should I use other ones?
I am using the same Ferrit Bead for Battery as of USB-C, is it ok?
As I am operating nRF52840 SoC on 3V, the ADC channel can only take a max of 3V as input, for that purpose I am using Zener Diode can you verify Battery Monitoring Circuit? (Zener Datasheet)
Now we have 2 power sources i.e, 5V from USB-C and 6V from the battery, for source selection I am using Schottky Barrier Diode Oring Scheme, can you verify its circuit? (Schottky Barrier Diode Datasheet)
I am using Linear voltage regulator HT7830 for getting 3V to run nRF52840 SoC. (Ht7830 Datasheet)
I am exposing pins to connect the micro and Reed switch, is it ok?
Do you recommend adding capacitors with motor driver IC? As shown in following Image:

Note: Please find attached a PDF file containing Schematic files for LL_V2.0

Thanks in advance

Regards,
Moghees Bin Zahid

devzone.nordicsemi.com/.../LL_5F00_V2.0_5F00_Schematics.pdf

RE: Verification for schematic for custom Board

Martin Sivertsen — Thu, 14 Oct 2021 10:15:08 GMT

Hello Moghees,

That's great to hear!

You're welcome.

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Moghees — Thu, 14 Oct 2021 08:27:33 GMT

Hi Martin,
Hope you are doing well, we have received the PCB v1.0 of hardware. It is working fine. Thanks for your brilliant support and feedback

Regards,
Moghees Bin Zahid

RE: Verification for schematic for custom Board

Moghees — Fri, 24 Sep 2021 17:22:19 GMT

Thank you for the support Martin

Regards,
Moghees Bin Zahid

RE: Verification for schematic for custom Board

Martin Sivertsen — Fri, 24 Sep 2021 13:44:20 GMT

Yes that should be fine.

Best regards,

Martin S.

RE: Verification for schematic for custom Board

Moghees — Fri, 24 Sep 2021 13:27:50 GMT

Hi Martin,
Thank you for the review

I want to confirm one thing

Previously I was using the following 12pF capacitor but now the PCB manufacturing facility has it out of stock:
C0G ±1% 12pF 50V 0402 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHS for details click here

I think in place of it I can use the following component:
C0G ±2% 12pF 50V 0402 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHS for details click here

Can you confirm if I am correct?

Once again Thank you very much for the review
Regards,
Moghees Bin zahid