LTC7802EUFDM-3.3 datasheet(10/34 Pages) AD

10 / 34 page

LTC7802-3.3

Rev. 0

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PIN FUNCTIONS

with this control voltage. Place compensation compo-

nents between the ITH pins and ground.

VOUT1, VFB2 (Pins 28,9): Controller Feedback Inputs.

Connect VOUT1 directly to the channel 1 output voltage.

Connect an external resistor divider between the channel 2

output voltage and the VFB2 pin to set the regulated VOUT2

voltage. Tie VFB2 to INTVCC to configure the channels for a

2-phase 3.3V output, in which both channels share VOUT1,

ITH1, and TRACK/SS1.

GND (Exposed Pad Pin 29): Ground. Connects to the

sources of the bottom N-Channel MOSFETs and the (–)

terminal(s) of decoupling capacitors. The exposed pad

must be soldered to PCB ground for rated electrical and

thermal performance.

within ±10% of its regulation point, the corresponding

PGOOD pin is pulled low.

TRACK/SS1, TRACK/SS2 (Pins 26,11): External Tracking

and Soft-Start Input. The LTC7802-3.3 regulates the nega-

tive input of the Error Amplifier (EA–) voltage to the lesser

of 0.8V or the voltage on the TRACK/SS1,2 pin. Internal

12.5µA pull-up current sources are connected to these

pins. A capacitor to ground sets the start-up ramp time to

the final regulated output voltage. The ramp time is equal

to 0.65ms for every 10nF of capacitance. Alternatively,

a resistor divider on another voltage supply connected

to the TRACK/SS pins allows the LTC7802-3.3 output to

track the other supply during start-up.

ITH1, ITH2 (Pins 27,10): Error Amplifier Outputs and

Switching Regulator Compensation Points. Each associ-

ated channel’s current comparator trip point increases

LTC7802EUFDM-3.3 Datasheet(PDF) 10 Page - Analog Devices