LTC3803 datasheet(6/16 Pages) LINER

6 / 16 page

LTC3803

3803fc

PIN FUNCTIONS

ITH/RUN (Pin 1): This pin performs two functions. It serves

as the error ampliﬁer compensation point as well as the

run/shutdown control input. Nominal voltage range is 0.7V

to 1.9V. Forcing this pin below the shutdown threshold

(VITHSHDN) causes the LTC3803 to shut down. In shutdown

mode, the NGATE pin is held low.

GND (Pin 2): Ground Pin.

VFB (Pin 3): Receives the feedback voltage from an external

resistive divider across the output.

SENSE (Pin 4): This pin performs two functions. It monitors

switch current by reading the voltage across an external

current sense resistor to ground. It also injects a current

ramp that develops slope compensation voltage across

an optional external programming resistor.

VCC (Pin 5): Supply Pin. Must be closely decoupled to

GND (Pin 2).

NGATE (Pin 6): Gate Drive for the External N-Channel

MOSFET. This pin swings from 0V to VCC.

BLOCK DIAGRAM

–

SLOPE

COMP

CURRENT

RAMP

VCC

GATE

DRIVER NGATE

SENSE

3803 BD

200kHz

OSCILLATOR

UNDERVOLTAGE

LOCKOUT

CURRENT

COMPARATOR

SHUTDOWN

COMPARATOR

SHUTDOWN

20mV

ITH/RUN

ERROR

AMPLIFIER

VFB

SOFT-

START

CLAMP

VCC

SHUNT

REGULATOR

SWITCHING

LOGIC AND

BLANKING

CIRCUIT

0.28V

VCC < VTURNON

0.3μA

VCC

–

GND

1.2V

800mV

REFERENCE

LTC3803 Datasheet(PDF) 6 Page - Linear Technology

LTC3803 Datasheet(HTML) 6 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Datasheet Download

Link URL