IR3080

VID = 11111X Fault

VID codes of 111111 and 111110 will set the fault latch and disable the error amplifier. An 800ns delay is provided

to prevent a fault condition from occurring during Dynamic VID changes.

Power Good Output

The PWRGD pin is an open-collector output and should be pulled up to a voltage source through a resistor. During

soft start, the PWRGD remains low until the output voltage is in regulation and SS/DEL is above 3.91V. The

PWRGD pin becomes low if the fault latch is set. A high level at the PWRGD pin indicates that the converter is in

operation and has no fault, but does not ensure the output voltage is within the specification. Output voltage

regulation within the design limits can logically be assured however, assuming no component failure in the system.

Load Current Indicator Output

The VDRP pin voltage represents the average current of the converter plus the DAC voltage. The load current can

be retrieved by a differential amplifier which subtracts the VDAC voltage from the VDRP voltage.

System Reference Voltage (VBIAS)

The IR3081 supplies a 6.8V/5mA precision reference voltage from the VBIAS pin. The oscillator ramp amplitude

tracks the VBIAS voltage, which should be used to program the Phase IC trip points to minimize phase delay errors.

Thermal Monitoring (VRHOT)

The IR3080 senses its own die temperature and produces a voltage at the input of the VRHOT comparator that is

proportional to temperature. An external resistor divider connected from VBIAS to the HOTSET pin and ground can

be used to program the thermal trip point of the VRHOT comparator. The VRHOT pin is an open-collector output

and should be pulled up to a voltage source through a resistor. If the thermal trip point is reached the VRHOT

output drives low. Pulling HOTSET above approximately 7.5V will disable the oscillator (used during factory testing).

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