Datasheet

UCD9244

SLVSAL6A –NOVEMBER 2010– REVISED FEBRUARY 2011

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Table 3. 6-bit VID Timing

SYMBO PARAMETER MIN TYP MAX UNITS

Tr Data and clock rise time – 2.5 µs

Tf Data and clock fall time – 0.3 µs

Tsu Data setup before changing clock 0 µs

Thd Data hold until next clock change 70 µs

Tchi Clock high time 70 125 µs

Tclo Clock low time 70 125 µs

Tvo Response time from rising edge of VID_S to start of 35 135 µs

Vout slewing to new setpoint

8-Bit VID Mode: In 8-bit VID mode, the four VID input signals are not used. Instead, an 8-bit VID code is

transmitted to the UCD9244 through the PMBus / I2C port using one of the VID_CODE_RAILn commands,

where n is the rail number from 1 to 4.

NAME DESCRIPTION

(1)

CODE

VID_CONFIG Selects the VID mode, sets the upper and lower voltage limits, and the starting voltage code at power-up. 0xBB

VID_CODE_RAIL1 Selects the VID code used to set the output voltage for Rail 1. 0xBC

VID_CODE_RAIL2 Selects the VID code used to set the output voltage for Rail 2. 0xBD

VID_CODE_RAIL3 Selects the VID code used to set the output voltage for Rail 3. 0xBE

VID_CODE_RAIL4 Selects the VID code used to set the output voltage for Rail 4. 0xBF

(1) For a complete description of the serial VID commands, see the UCD92xx PMBus Command Reference(SLUU337)

Product Folder Link(s) :UCD9244