LTC3255 datasheet(6/16 Pages) LINER

6 / 16 page

LTC3255

3255f

For more information www.linear.com/LTC3255

PIN FUNCTIONS

C+ (Pin 1): Flying Capacitor Positive Connection. This pin

must not be driven externally.

VOUT (Pin 2): Charge Pump Output Voltage.

FB (Pin 3): Feedback pin for setting the regulated output

voltage, usually connected to VOUT through an external

resistor divider. In operation, the LTC3255 servos the FB

pin to 1.2V by transferring charge from VIN to VOUT.

SHUNT (Pin 4): Configuration pin that must connect to

either the BIAS or GND pins to enable or defeat, respec-

tively, the LTC3255’s shunt regulator feature. Connect this

pin to either BIAS or GND on the circuit board layout. Do

not float this pin.

PGOOD (Pin 5): Power Good Open-Drain Logic Output.

This pin becomes high impedance when the feedback

voltage on the FB pin rises above 94% (typical) of the

regulation voltage.

EN (Pin 6): Logic Input. A logic high on the EN pin will

enable the charge pump. A logic low shuts down the

LTC3255. Do not float this pin.

BIAS (Pin 7): Connect this pin to a 0.1µF bypass capaci-

tor to GND. A ceramic capacitor of at least 10V rating is

recommended.

GND(Pin8andExposedPadPin11):GroundConnection.

Exposed pad (Pin 11) must be soldered to the circuit board

groundplaneforproperthermalandelectricalconduction.

C– (Pin 9): Flying Capacitor Negative Connection. This pin

must not be driven externally.

VIN (Pin 10): Input Supply Voltage. Bypass this pin to GND

with at least 1µF capacitance.

LTC3255 データシート(PDF) 6 Page - Linear Technology