LS2088A - Voltage Identification (VID) Controller Requirements

[victorhdz]

I working on a power supply to provide the power for a LS2088A, and I am trying to understand the Voltage Identification (VID) controller requirements.

I see from the data sheet and there is a requirement on the accuracy of ±30 mV, so:

• Does that mean that if the VID Voltage is set to 1.025-V it would be OK to operate at 0.995-V even though it overlaps with other VID Voltage (namely 1.000-V)?

I am also curious about timing requirements, once LS2088A "requests" a change in the VID Voltage:

• Is there a timing requirement expectation for the transition from one VID Voltage to another?

Finally, I am curious about Voltage Identification (VID) in general - Is that an Industry Standard that you follow? or is the VID specific to NXP and/or the given device (e.g. LS2088A)

Thanks!

[Bulat]

1. Yes, VDD can overlap neighbouring VID levels.

2. We do not specify exact timing of VDD change. As you can find, we say following: "It is expected that the chip's boot code reads the FUSESR value very early in the boot sequence and updates the regulator accordingly"

3. We have several high speed processors with VID feature, besides LS2088A these for example are T4240, LS1088A, LX2160A.

I am not sure if such a standard exists. However many other companies besides NXP use "VID" to specify core's voltages on high speed processors. This for example can be found in PC's BIOS settings.

Regards,

Bulat

[victorhdz]

If I go by this statement: "It is expected that the chip's boot code reads the FUSESR value very early in the boot sequence and updates the regulator accordingly".

Does that mean that the VID only changes once at turn on and it does NOT dynamically change during operation?

[Bulat]

Yes, it does.

Regards,

Bulat