Datasheet

LTC3827
9
3827ff
PIN FUNCTIONS
TRACK/SS1, TRACK/SS2 (Pins 29, 13): External Track-
ing and Soft-Start Input. The LTC3827 regulates the
V
FB1,2
voltage to the smaller of 0.8V or the voltage on the
TRACK/SS1,2 pin. A internal 1µA pull-up current source
is connected to this pin. A capacitor to ground at this
pin sets the ramp time to fi nal regulated output voltage.
Alternatively, a resistor divider on another voltage supply
connected to this pin allows the LTC3827 output to track
the other supply during startup.
I
TH1,
I
TH2
(Pins 30, 12): Error Amplifi er Outputs and
Switching Regulator Compensation Points. Each associ-
ated channel’s current comparator trip point increases
with this control voltage.
V
FB1
, V
FB2
(Pins 31, 11): Receives the remotely sensed
feedback voltage for each controller from an external
resistive divider across the output.
SENSE1
+
, SENSE2
+
(Pins 32, 10): The (+) Input to the
Differential Current Comparators. The I
TH
pin voltage and
controlled offsets between the SENSE
–
and SENSE
+
pins in
conjunction with R
SENSE
set the current trip threshold.
Exposed Pad (Pin 33): SGND. Must be soldered to the
PCB.