MIC2267YML TR Microchip

MIC2267 Input Current Limiting Synchronous Buck Regulator USB Power Maximizer General Description Features Input voltage range: 3.0V to 5.5V The MIC2267 is a USB Power Maximizer which transfers the maximum power from the limited USB current Output voltage adjustable down to 1.0V source by shaping the input current limit profile. It Up to 96% efficiency at 500mA output incorporates a high efficiency, integrated synchronous step Efficiency >90% across a broad load range down regulator. Internal 150m switches and adjustable Fast transient response operating frequency allows the MIC2267 to achieve greater than 90% efficiency across a broad load range. It Adjustable frequency from 400kHz to 1.5MHz replaces the USB current limit switch, 5V buck regulator Adjustable input current limiting 100mA to over 1A and minimizes capacitance for many USB applications. 100% maximum duty cycle The adjustable frequency control can be utilized to move Fully integrated MOSFET switches harmonics away from sensitive frequency bands. Micropower shutdown The MIC2267 allows the input current limit profile to be Thermal shutdown and output current limit protection shaped for various applications. With a current mode control with external compensation, the MIC2267 transient 12-pin 3mm x 3mm MLF response can be optimized over load and output Junction temperature range: 40C to +125C capacitance making it highly flexible for many applications. Additional features include 1A shutdown current, output Applications current limit and thermal shutdown protection. The USB power MIC2267 is available in a 12-pin 3mm x 3mm MLF with a Wireless router cards junction operating range from 40C to +125C. General buck converter applications Datasheets and support documentation can be found on Micrels web site at: www.micrel.com. Typical Application Efficiency vs. Output Current 100 V = 4.2V IN 95 90 V = 5.5V IN 85 80 75 70 65 60 V = 3.3V OUT 55 50 00.5 11.5 2 OUTPUT CURRENT (A) MIC2267 USB Input Current Limiting Synchronous Buck Regulator Efficiency 5V to 3.3V IN OUT USB Power Maximizer is a trademark of Micrel, Inc. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel Inc. MIC2267 Ordering Information (1) Part Number Voltage Mark Code Temperature Range Package MIC2267YML Adjustable 2267 40C to +125C 12-Pin 3mm x 3mm MLF Note: 1. Package is GREEN RoHS compliant. Lead finish is NiPdAu. Mold compound is halogen free. Pin Configuration 12-Pin 3mm x 3mm MLF (ML) (Top View) Pin Description Pin Number Pin Name Pin Function 1 Analog Ground: The ground return for the low power blocks of the MIC2267. AGND Feedback (Input): Input to the error amplifier. Connect a resistor divider between VOUT and 2 FB ground to adjust the output voltage. Compensation Pin: Output of the internal gm error amplifier. Place a series connected, 3 COMP Resistor and Capacitor to GND for external compensation. Power Good (Output): Open drain of an N-Channel MOSFET. Connect a resistor to VIN or 4 PGOOD VOUT for power good signalling. 5 SW Switch (Output): Internal power MOSFET output switches. 6 PGND Power Ground: The ground return for the switching currents. 7 VIN Power Supply Voltage (Input): Requires bypass capacitor to GND Enable/Delay (Input): Apply a Logic High to start the device. Apply Logic Low to stop the 8 EN device placing it in a low quiescent current mode. Input Current Limit Filter: Place a capacitor to VIN to adjust the time constant for the input 9 FILTER current limit filter. Input Current Limit: Place a resistor to ground to adjust the average current limit from the input 10 LIMIT supply. 11 Slope Compensation: Sets current mode slope compensation SLOPEC Frequency Control: The switching frequency is adjusted from 400kHz to 1.5MHz with a resistor 12 FREQ from this pin to ground. Exposed Heatsink Pad: Thermal connection between die and external ground plane. A solid ePAD connection to a large ground plane is required for full output power. This pad must be HS Pad connected to ground. M9999-011711-A January 2011 2