MIC2203 High Efficiency 1MHz Synchronous Buck Regulator General Description Features The Micrel MIC2203 is a high efficiency 1MHz PWM Input voltage range: 2.3V to 5.5V synchronous buck switching regulator. The MIC2203 Output voltage adjustable down to 0.5V features low noise constant frequency PWM 300mA output current operation with a low dynamic supply current of Constant 1MHz PWM switching frequency <1mA. The low noise and efficient operation both make the MIC2203 well suited for sensitive RF, and > 95% efficiency audio power applications. < 1mA switching supply current The MIC2203 operates from 2.3V to 5.5V input and < 350A static quiescent current can supply over 300mA of output current with output < 1A shutdown current voltages down to 0.5V. Additionally, the MIC2203 All-ceramic capacitors can be synchronized to an external clock, or multiple Easily synchronized to external clock MIC2203s can easily be daisy-chained with the SYNCLOCK feature. SYNCLOCK feature to daisy chain multiple devices The MIC2203 has a high loop bandwidth with corresponding ultra fast transient response times. Thermal shutdown and current limit protection This reduces the output capacitor size, and is very 10 pin MSOP, and 3mm x 3mm MLF-10L package useful when powering applications that require fast options dynamic response such as CPU cores and RF 40C to +125C junction temperature range circuitry in high performance cellular phones and PDAs. Applications The MIC2203 is available in 10-pin MSOP and 802.11 WLAN modules 3mm x 3mm MLF-10L package options with an MD players operating junction temperature range from 40C to MP3 players 125C. Typical Application 10H 1.8V 300mA MIC2203BMM 1 10 2.3V to 5.5V R1 2 9 10k SYNC IN 2.2F 3 8 1F SYNC OUT 4 7 10nF EN 5 6 R2 3.83k High Efficiency Buck Regulator MicroLead Frame and MLF are trademarks of Amkor Technologies. Micrel, Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax +1 (408) 474-1000 Micrel, Inc. MIC2203 Ordering Information Part Number Output Voltage Junction Temperature Package Range Standard Pb-Free MIC2203BMM MIC2203YMM Adjustable -40C to +125C MSOP-10L MIC2203BML MIC2203YML Adjustable -40C to +125C 3mm x 3mm MLF-10L Pin Configuration MLF-10 (ML) MSOP-10 (MM) Top View Pin Description Pin Number Pin Name Pin Function 1 SW Switch (Output): Internal power MOSFET output switches. 2 VIN Supply Voltage (Input): Requires a bypass capacitor to GND. 3 SYNC IN SYNC IN for the MIC2203, Sync the main switching frequency to a external clock. Should be tied to ground when not in use. 4 SYNC OUT SYNC OUT a 50ns wide sync pulse to feed into SYNC IN on MIC2203. Can be left open or tied to ground when not used. 5 EN A low level EN will power down the device, reducing the quiescent current to under 1A. 6 FB Input to the error amplifier, connect to the external resistor divider network to set the output voltage. 7 BIAS Internal circuit bias supply, nominally 2.3V. Must be de-coupled to signal ground and can have a minimum of external DC loading. 8,9,10 GND Ground EP GND Exposed backside pad, connect to Ground (MLF option only) M9999-120604 December 2004 2 (408) 955-1690