Datasheet LTC3803 (Analog Devices) - 6
| Fabricante | Analog Devices |
| Descripción | Constant Frequency Current Mode Flyback DC/DC Controller in ThinSOT |
| Páginas / Página | 16 / 6 — PIN FUNCTIONS. ITH/RUN (Pin 1):. SENSE (Pin 4):. VCC (Pin 5):. GND (Pin … |
| Formato / tamaño de archivo | PDF / 173 Kb |
| Idioma del documento | Inglés |
PIN FUNCTIONS. ITH/RUN (Pin 1):. SENSE (Pin 4):. VCC (Pin 5):. GND (Pin 2):. VFB (Pin 3):. NGATE (Pin 6):. BLOCK DIAGRAM
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LTC3803
PIN FUNCTIONS ITH/RUN (Pin 1):
This pin performs two functions. It serves
SENSE (Pin 4):
This pin performs two functions. It monitors as the error amplifi er compensation point as well as the switch current by reading the voltage across an external run/shutdown control input. Nominal voltage range is 0.7V current sense resistor to ground. It also injects a current to 1.9V. Forcing this pin below the shutdown threshold ramp that develops slope compensation voltage across (VITHSHDN) causes the LTC3803 to shut down. In shutdown an optional external programming resistor. 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 200kHz 1.2V CURRENT 2 OSCILLATOR RAMP SENSE 4 ITH/RUN 1 3803 BD 3803fc 6 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS BLOCK DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATIONS RELATED PARTS
PIN FUNCTIONS ITH/RUN (Pin 1):
This pin performs two functions. It serves
SENSE (Pin 4):
This pin performs two functions. It monitors as the error amplifi er compensation point as well as the switch current by reading the voltage across an external run/shutdown control input. Nominal voltage range is 0.7V current sense resistor to ground. It also injects a current to 1.9V. Forcing this pin below the shutdown threshold ramp that develops slope compensation voltage across (VITHSHDN) causes the LTC3803 to shut down. In shutdown an optional external programming resistor. 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 200kHz 1.2V CURRENT 2 OSCILLATOR RAMP SENSE 4 ITH/RUN 1 3803 BD 3803fc 6 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS BLOCK DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATIONS RELATED PARTS