Max power consumption - confusion

[kster59]

After reading the datasheet and the special power considerations pdf,
https://www.xmos.com/published/xs1l_power

I am still confused what is the maximum power the L1 and L2 devices use in order to size the power supply. This is an important consideration when the USB port can only put out 5V @ 500mA.

So what is the bottom line for the 1v VDDIO and 3.3v VDD? I read somewhere it was 300mA for an L1 and 600mA for an L2 on the VDDIO but the datasheet makes it very tricky to determine.

On the reference design the L1 has a 600mA switching power supply but the L2 has a 1.5A switching. On the XC-1A, the LTC3417 can also put out 1.5A on the 1v supply max but it is a G4 processor with 4 cores.

Is 300mA enough for a L1 design?

Is 600mA enough for an L2 design?

[Joe]

Hi,

This is covered in the XS1-L Hardware Design Checklist:

http://www.xmos.com/system/files/xs1-l-des-check.pdf

On the 1.0V VDD core supply the current consumption will be less than 300mA for an L1 and 600mA for an L2. Supplies are normally overrated by as much as 200% in order to operate at the maximum efficiency.

Regards,
Joe