Maker : Fairchild Semiconductor
Part No. : RC5054

  Datasheet PDF : RC5054.pdf
  Cross Reference : RC5054 Cross Reference
  Buy Component : RC5054 Find Stock and Price

Shortcut : RC5051  RC5054  RC5054A  RC5057  RC5057M  RC5058 

Product Information

www.fairchildsemi.com RC5054A Programmable Synchronous DC-DC Converter Controller for Low Voltage Microprocessors Features • Drives Two N-Channel MOSFETs • Operates from +5V Power Input • Simple Single-Loop Control Design - Voltage-Mode PWM Control • Fast Transient Response - High-Bandwidth Error Amplifier - Full 0% to 100% Duty Ratio • Excellent Output Voltage Regulation • TTL Compatible 5 Bit Digital-to-Analog Output Voltage Selection - Wide Range - 1.3VDC to 3.5VDC - 0.1V Binary Steps from 2.1VDC to 3.5VDC - 0.05V Binary Steps from 1.3VDC to 2.1VDC • Power-Good Output Voltage Monitor • Over-Voltage and Over-Current Fault Monitors - Does Not Require Extra Current Sensing Element, Uses MOSFET’s RDS(ON) • Small Converter Size - Constant Frequency Operation - 200kHz Free-Running Oscillator Programmable from 50kHz to 1MHz Applications • Power Supply for Pentium®, Pentium Pro, PowerPC™ and Alpha™ Microprocessors • High-Power 5V to 3.xV DC-DC Regulators • Low-Voltage Distributed Power Supplies Description The RC5054A provides complete control and protection for a DC-DC converter optimized for high-performance microprocessor applications. It is designed to drive two N-Channel MOSFETs in a synchronous-rectified buck topology. The RC5054A integrates all of the control, output adjustment, monitoring and protection functions into a single package. The output voltage of the converter is easily adjusted and precisely regulated. The RC5054A includes a 5-input digitalto-analog converter (DAC) that adjusts the output voltage from 2.1VDC to 3.5VDC in 0.1V increments and from 1.3VDC to 2.1VDC in 0.05V steps. The RC5054A provides simple, single feedback loop, volt- Block Diagram VCC VSEN 110% + POWER-ON RESET (POR) - PGOOD 90% + 115% + OVERVOLTAGE 10µA OVP SOFTSTART OVERCURRENT 4V SS BOOT UGATE PHASE VID0 VID1 VID2 VID3 VID4 FB COMP GND RT OSCILLATOR D/A CONVERTER (DAC) DACOUT + PWM COMPARATOR GATE CONTROL LOGIC LGATE PGND - + OCSET REFERENCE 200µA - + INHIBIT PWM - ERROR AMP Rev. 1.0.2 Alpha is a trademark of Digital Equipment Corporation. Pentium is a registered trademark of Intel Corporation. PowerPC is a trademark of IBM Corporation. RC5054A PRODUCT SPECIFICATION age-mode control with fast transient response. It includes a 200KHz free-running triangle-wave oscillator that is adjustable from 50KHz to 1MHz. The error amplifier features a 15MHz gain-bandwidth product and 6V/µs slew rate which enables high converter bandwidth for fast transient performance. The resulting PWM duty ratio ranges from 0% to 100%. The RC5054A monitors the output voltage with a window comparator that tracks the DAC output and issues a Power Good signal when the output is within ±10%. The RC5054A protects against over-current conditions by inhibiting PWM operation. Built-in over-voltage protection triggers an external SCR to crowbar the input supply. The RC5054A monitors the current by using the RDS(ON) of the upper MOSFET which eliminates the need for a current sensing resistor. Pin Assignments RC5054 (SOIC) TOP VIEW VSEN OCSET SS VID0 VID1 VID2 VID3 VID4 COMP FB 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 RT OVP VCC LGATE PGND BOOT UGATE PHASE PGOOD GND Pin Definitions Pin Number Pin Names 1 VSEN Pin Function Description This pin is connected to the converter’s output voltage. The PGOOD and OVP comparator circuits use this signal to report output voltage status and for overvoltage protection. Connect a resistor (ROCSET) from this pin to the drain of the upper MOSFET. ROCSET, an internal 200µA current source (IOCS), and the upper MOSFET onresistance (RDS(ON)) set the converter over-current (OC) trip point according to the following equation: I OCS • R OCSET I PEAK = --------------------------------------R DS ( ON ) 2 OCSET An over-current trip cycles the soft-start function. 3 4-8 SS VID0-VID4 Connect a capacitor from this pin to ground. This capacitor, along with an internal 10µA current so...

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