K70 - Running VDD and VDDINT at different levels

[markoseverin]

Hi guys,

I'm just starting out with the K70 and one thing i've noticed is that on the K70 Tower, the VDDINT (core power) is powered from 3.3V. Wouldn't it make more sense to power the VDDINT from a 1.8V supply and thus save power? I went through the datasheet and I didn't find the info, if the VDDINT can be run on a lower level than VDD, i.e. VDD on 3.3V and VDDINT on 1.8V. Can this be done?

Also, i've noticed that the K70 tower is routed on a 12-layer PCB. You can route a Core I7 on a 12 layer PCB. Why did freescale decide to do so for a microcontroller?

Thanks and best regards,

Marko Severin

[apanecatl · Accepted solution]

Hi Marko, the reason for seeing two different voltage levels is that VDD_INT refers to the internal regulated voltage the platform supports to the core thus allowing to have a broader voltage compatibility so you can attach the device to a system with voltage levels between 1.8-3.6V. If your whole systems works at 1.8V that is great because K70 can work without any problem since VDD = VDD_INT = 1.8V.

Regarding the 12 layer PCB, it was a designer's choice due to the large mount of components the board features like the 1GB NAND Flash memory, SD card interface, Flex bus, LCDC dedicated bus, and the increased number of GPIOs and headers.

[markoseverin]

Thanks Pedro for clearing that up!

About the 12 Layer PCB, I just thought that it was strange that a K70 board was routed on 12 layers, while the three I.MX6 development boards are all done on 8.

Thanks again!

Marko