Datasheet LTC1771 (Analog Devices) - 5

LTC1771
U U U PI FU CTIO S RUN/SS (Pin 1):
The voltage level on this pin controls
PGATE (Pin 5):
High Current Gate Driver for External shutdown/run mode (ground = shutdown, open/high = P-Channel MOSFET Switch. Voltage swing is from ground run). Connecting an external capacitor to this pin provides to VIN. soft-start.
VIN (Pin 6):
Main Input Voltage Supply Pin.
ITH (Pin 2):
Error Amplifier Compensation Point. The
SENSE (Pin 7):
Current Sense Input for Monitoring Switch current comparator threshold increases with this control Current. Maximum switch current and Burst Mode voltage. Nominal voltage range for this pin is 0V to 3V. threshold is programmed with an external resistor be-
VFB (Pin 3):
Feedback of Output Voltage for Comparison tween SENSE and VIN. to Internal 1.23V Reference. An external resistive divider
MODE (Pin 8):
Burst Mode Enable/Disable Pin. Connect- across the output is returned to this pin. ing this pin to VIN (or above 2V) enables Burst Mode
GND (Pin 4):
Ground Pin. operation, while connecting this pin to ground disables Burst Mode operation. Do not leave floating.
U U W FUNCTIONAL BLOCK DIAGRA
V V IN IN 6 VIN + 1µA C C SS READY RUN/SS IN 1.23V REFERENCE 1 22k R MODE SENSE (BURST ENABLE) 8 10% CURRENT ON SOFT-START – 1.23V + EA C SENSE ON + – 7 10% CURRENT VOUT SLEEP * 250k ITH 2 2V RC 1V READY BLANKING CC V GND IN – PGATE 4 B 1V + 5 MODE ON TRIGGER D1 *OPTIONAL FOR FOLDBACK L CURRENT LIMITING 1-SHOT 3.5µs STRETCH VOUT R2 VFB + 3 COUT R1 1771 BD 5