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Microchip MCP1603L

2.0 MHz, 500 mA Synchronous Buck Regulator


TopologyBuck Converter
Input voltage2.7-5.5 V
Switching frequency1500-2800 kHz
Output 11.2 V / 0.5 A
Output 24.5 V
Output 32.5 V / 0.5 A
Output 41.8 V / 0.5 A
Output 51.5 V / 0.5 A
Output 63.3 V / 0.5 A
IC revisionB


The MCP1603/B/L is a high-efficiency, fully-integrated 500 mA synchronous buck regulator whose 2.7V to 5.5V input voltage range makes it ideally suited for applications powered from 1-cell Li-Ion or 2-cell/3-cell NiMH/NiCd batteries.At heavy loads, the MCP1603/B/L operates in the 2.0 MHz fixed frequency pulse-width modulation (PWM) mode, which provides a low noise, low-output ripple, small-size solution. When the load is reduced to light levels, the MCP1603/L automatically changesoperation to a Pulse Frequency Modulation (PFM)mode to minimize quiescent current draw from thebattery. No intervention is necessary for a smoothtransition from one mode to another. These two modesof operation allow the MCP1603/L to achieve thehighest efficiency over the entire operating currentrange.The MCP1603B device disables the PFM modeswitching, and operates only in normal PWM modeover the entire load range (without skipping).MCP1603B is for applications that cannot tolerate thelow-frequency output ripple associated with PFMswitching.The MCP1603/B/L family is available with either anadjustable or fixed-output voltage. The available fixedoutput voltage options for MCP1603/L are 1.2V, 1.5V,1.8V, 2.5V and 3.3V, and for MCP1603B are 1.8 and3.3V. When a fixed option is used, only three additionalsmall external components are needed to form acomplete solution. Couple this with the low profile,small-foot print packages and the entire systemsolution is achieved with minimal size.Additional protection features include: UVLO,overtemperature and overcurrent protection


  • Over 90% Typical Efficiency
  • Output Current Up To 500 mA
  • Low PFM Quiescent Current = 45 μA, typical(MCP1603/L)
  • Low Shutdown Current = 0.1 μA, typical
  • Adjustable Output Voltage:
  • 0.8V to 4.5V
  • Fixed Output Voltage:
  • 1.2V, 1.5V, 1.8V, 2.5V, 3.3V (MCP1603/L)
  • 1.8V, 3.3V (MCP1603B)
  • 2.0 MHz Fixed-Frequency PWM (Heavy Load)
  • Automatic PWM-to-PFM ModeTransition(MCP1603/L)
  • PWM Mode Only Option (MCP1603B)
  • 100% Duty Cycle Operation
  • Internally Compensated
  • Undervoltage Lockout (UVLO)
  • Overtemperature Protection
  • Space Saving Packages:
  • 5-Lead TSOT, Two Pinout Types (MCP1603/L)
  • 8-Lead 2 x 3 DFN

Typical applications

  • +5V or +3.3V Distributed Systems
  • Organizers / PDAs
  • Digital Cameras
  • Headsets
  • Portable Equipment
  • Portable Computers
  • Cellular Telephones
  • USB Powered Devices