LTC3255_15 Datasheet, PDF (6/16 Pages) Linear Technology – Wide VIN Range Fault Protected 50mA Step-Down Charge Pump

LTC3255
PIN FUNCTIONS
C⁺ (Pin 1): Flying Capacitor Positive Connection. This pin
must not be driven externally.
V_OUT (Pin 2): Charge Pump Output Voltage.
FB (Pin 3): Feedback pin for setting the regulated output
voltage, usually connected to V_OUT through an external
resistor divider. In operation, the LTC3255 servos the FB
pin to 1.2V by transferring charge from V_IN to V_OUT.
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 (Pin 8 and Exposed Pad Pin 11): Ground Connection.
Exposed pad (Pin 11) must be soldered to the circuit board
ground plane for proper thermal and electrical conduction.
C^– (Pin 9): Flying Capacitor Negative Connection. This pin
must not be driven externally.
V_IN (Pin 10): Input Supply Voltage. Bypass this pin to GND
with at least 1µF capacitance.
3255f
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For more information www.linear.com/LTC3255