LTC4449 datasheet(73/108 Pages) LINER

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LTC3882-1

Rev A

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OPERATION

The OPERATION command is used to turn the PWM channel on and off in conjunction with RUN pin hardware control.

This command may also be used to move the output voltage to margin levels. VOUT changes commanded by OPERATION

margin commands occur at the programmed VOUT_TRANSITION_RATE. The unit stays in the commanded operating

state until an OPERATION command or RUN pin voltage instructs the device to change to another state.

Execution of margin commands is delayed until any on-going TON_RISE or TOFF_FALL output sequencing is com-

pleted. Margin values are affected by AVP function, if enabled. Margin operations that ignore faults are not supported

by the LTC3882-1.

Supported Values:

VALUE

MEANING

0xA8

Margin high.

0x98

Margin low.

0x80

On (VOUT back to nominal even if bit 3 of ON_OFF_CONFIG is not set).

0x40*

Soft off (with sequencing).

0x00*

Immediate off (no sequencing).

*Device does not respond to these commands if bit 3 of ON_OFF_CONFIG is not set.

Programming an unsupported OPERATION value will generate a CML fault and the command will be ignored.

This command has one data byte.

MFR_RESET

This command provides a means to reset the LTC3882-1 from the serial bus. This forces the LTC3882-1 to turn off

both PWM channels, load the operating memory from internal EEPROM, clear all faults and then perform a soft-start

of both PWM channels, if enabled.

This write-only command has no data bytes.

PMBus COMMAND DETAILS (On, Off and Margin Control)

LTC4449 Datasheet(PDF) 73 Page - Linear Technology