Datasheet LTC3803-3 (Analog Devices) - 6

LTC3803-3
PIN FUNCTIONS ITH/RUN (Pin 1):
This pin performs two functions. It
SENSE (Pin 4):
This pin performs two functions. It monitors serves as the error amplifi er compensation point as well switch current by reading the voltage across an external as the run/shutdown control input. Nominal voltage range current sense resistor to ground. It also injects a current is 0.7V to 1.9V. Forcing this pin below the shutdown ramp that develops slope compensation voltage across threshold (VITHSHDN) causes the LTC3803-3 to shut down. an optional external programming resistor. In shutdown mode, the NGATE pin is held low.
VCC (Pin 5):
Supply Pin. Must be closely decoupled to
GND (Pin 2):
Ground Pin. GND (Pin 2).
VFB (Pin 3):
Receives the feedback voltage from an external
NGATE (Pin 6):
Gate Drive for the External N-Channel resistive divider across the output. MOSFET. This pin swings from 0V to VCC.
BLOCK DIAGRAM
5 VCC SHUTDOWN COMPARATOR 0.3μA 0.28V + VCC < VTURNON V UNDERVOLTAGE CC SHUNT LOCKOUT 800mV REGULATOR – REFERENCE SHUTDOWN SOFT- START CLAMP CURRENT – COMPARATOR VCC ERROR + AMPLIFIER GATE SWITCHING R DRIVER + NGATE LOGIC AND Q 6 V BLANKING FB 3 – S CIRCUIT SLOPE COMP 20mV GND 300kHz 1.2V CURRENT 2 OSCILLATOR RAMP SENSE 4 ITH/RUN 1 38033 BD 38033fd 6 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS BLOCK DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS