LTC4263 datasheet(13/28 Pages) LINER

13 / 28 page

LTC4274

4274fa

PIN FUNCTIONS

OUT: Output Voltage Monitor. OUT should be connected

to the output port. A current limit foldback circuit limits

the power dissipation in the external MOSFET by reduc-

ing the current limit threshold when the drain-to-source

voltage exceeds 10V. The Power Good bit is set when the

voltage from OUT to VEE drops below 2.4V (typ). A 500k

resistor is connected internally from OUT to AGND when

the port is idle.

VEE: Main Supply Input. Connect to a –45V to –57V

supply, relative to AGND.

AUTO: AUTO Pin Mode Input. AUTO pin mode allows the

LTC4274 to detect and power up a PD even if there is no

host controller present on the I2C bus. The voltage of the

AUTO pin determines the state of the internal registers

when the LTC4274 is reset or comes out of VDD UVLO

(see the Register map). The states of these register bits

can subsequently be changed via the I2C interface. The

real-time state of the AUTO pin is read at bit 0 in the Pin

Status register (11h). Internally pulled down to DGND.

Must be tied locally to either VDD or DGND.

MSD: Maskable Shutdown Input. Active low. When pulled

low, all ports that have their corresponding mask bit set

in the Misc Config register (17h) will be reset, equivalent

to pulling the SHDN pin low. Internal filtering of the MSD

pin prevents glitches less than 1μs wide from resetting

ports. Internally pulled up to VDD.

LTC4263 データシート(PDF) 13 Page - Linear Technology