Datasheet ADP1851 (Analog Devices) - 8

ADP1851 Data Sheet Pin No. Mnemonic Description
16 FREQ Internal Oscillator Frequency, fOSC. Sets the desired operating frequency between 200 kHz and 1.5 MHz with one resistor between FREQ and AGND. Connect FREQ to AGND for a preprogrammed 300 kHz, or tie FREQ to VCCO for 600 kHz operating frequency. EPAD (AGND) Exposed Pad, Analog Ground. The exposed pad is the AGND power input of the IC. Connect the exposed pad to the system AGND plane. Rev. B | Page 8 of 24 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION TYPICAL OPERATION CIRCUIT REVISION HISTORY SIMPLIFIED BLOCK DIAGRAM SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION CONTROL ARCHITECTURE OSCILLATOR FREQUENCY SYNCHRONIZATION PWM AND PULSE SKIP MODES OF OPERATION SYNCHRONOUS RECTIFIER AND DEAD TIME INPUT UNDERVOLTAGE LOCKOUT INTERNAL LINEAR REGULATOR OVERVOLTAGE PROTECTION POWER GOOD SHORT-CIRCUIT AND CURRENT-LIMIT PROTECTION ENABLE/DISABLE CONTROL THERMAL OVERLOAD PROTECTION APPLICATIONS INFORMATION ADIsimPower DESIGN TOOL SETTING THE OUTPUT VOLTAGE SOFT START SETTING THE CURRENT LIMIT ACCURATE CURRENT-LIMIT SENSING INPUT CAPACITOR SELECTION VIN PIN FILTER BOOST CAPACITOR SELECTION INDUCTOR SELECTION OUTPUT CAPACITOR SELECTION MOSFET SELECTION LOOP COMPENSATION—VOLTAGE MODE Type III Compensation LOOP COMPENSATION—CURRENT MODE Setting the Slope Compensation Setting the Current Sense Gain Type II Compensation SWITCHING NOISE AND OVERSHOOT REDUCTION VOLTAGE TRACKING Coincident Tracking Ratiometric Tracking PCB LAYOUT GUIDELINES TYPICAL OPERATING CIRCUITS OUTLINE DIMENSIONS ORDERING GUIDE