Datasheet

LTC3861
10
3861fa
For more information www.linear.com/LTC3861
pin FuncTions
CONFIG (Pin 33): Line Feedforward Configuration Pin.
This pin allows the user to configure the multiplier to
achieve
accurate modulator gain over varying V
IN
and
switching frequencies. This pin can be connected to V
CC
or SGND. An internal resistor will pull this pin to SGND
when it is floated.
TRACK/SS1 (Pin 35), TRACK/SS2 (Pin 11): Combined
Soft-Start and Tracking Inputs. For soft-start operation,
connecting a capacitor from this pin to ground will control
the voltage ramp at the output of the power supply. An
internal 2.5μA current source will charge the capacitor and
thereby control an extra input on the reference side of the
error amplifier. For tracking operation, this input allows the
start-up of a secondary output to track a primary output
according to a ratio established by a resistor divider from
the primary output to the secondary error amplifier track
pin. For coincident tracking of both outputs at start-up,
a resistor divider with values equal to those connected
to the secondary VSNSP pin from the secondary output
should be used to connect the secondary track input
from the primary output. This pin is internally clamped
to 1.2V, and is used to
communicate
over current events
in a master-slave configuration.
V
CC
(Pin 36): Chip Supply Voltage. Bypass this pin to GND
with a capacitor (0.1µF to 1µF ceramic) in close proximity
to the chip.