KW36, without radio

[roleksuk]

Have a new version of a board using KW36Z, but this one will not be using the radio aspects of the chip at all.

And yes, we do wish to use the KW36Z for this board.

Obviously there are things that can be done in software to disable the radio sections of the chip.

I'm wondering what can be done in hardware.

I can find no guidelines for safe/appropriate connections when not using the radio.

This includes power for RF (VDD_RFx), the antenna pins, etc.

The chip will be operating in bypass mode, as there is already a 3.3V supply on board.

Sleep/quiescent current levels are a very significant issue.

[roleksuk]

1. In a related point, your datasheet appears to specify the crystal in terms of the RF section's tight requirements...

Since we are not using the RF features, can we use the crystals below (equivalent to each other), with very similar specs, but modestly relaxed tolerance & stability, given we won't be needing to adhere to BLE etc specifications:

ABM11AIG-32000MHZ-4Z-T3

ECS-320-10-37Q-ES-TR

If not, is there a specification that we could use in lieu of the ultra-tight ones listed in the datasheet? Perhaps from another chip that does not have the RF section?

2. And the 3pF caps on PTC1, PTC2, PTC3, and PTC4 recommended in your ap-note AN12181 - are they needed given that the RF section is not going to be activated?

[stephanie_m]

Hello,

Are you going to use the low power capabilities of the device ?

Regards,

Estephania

[roleksuk]

Yes, we'll be using low power features.

We will not be using internal DCDC (operating in bypass mode).

We'll be using uart, i2c (master & slave), SPI (master & slave), no 32kHz crystal, gpio wake, perhaps a high drive io pin, gpio.

(added here, since the other thread has a typo in thread title)

[roleksuk]

answered in other thread.

[stephanie_m]

Hello,

We will keep the communication through the other post then

Regards

[roleksuk]

Yes!

[stephanie_m]

Hello,

We do not have a guide for it, nonetheless,  as you will use CAN it means you need to connect the VDD_RF supply and you can follow the current power connection suggestion on VDD_RFx pins.

If you are not using the ANT, you can leave them floating but please connect GANT to ground.

Regards,
Estephania

[stephanie_m]

Will you use CAN in your project?