MIC2224YML-EV Microchip

MIC2224 High Efficiency 2MHz PWM Buck Converter with DAC Input and 40m Bypass Switch General Description Features The MIC2224 is a high efficiency 2MHz PWM synchronous 2.7V to 5.5V input voltage range buck switching regulator optimized for powering 2.5G and DAC-adjustable output voltage down to 0.3V 3G CDMA RF Power Amplifiers. The output voltage of 600mA output current in PWM mode MIC2224 can be dynamically adjusted with an external Internally protected 40m bypass switch DAC to maximize PA efficiency versus required output power. When the PA requires the highest power, the DAC Allows direct connection of battery to load can be used to enable a low on-resistance, 40m , bypass Over 95% efficient switch that powers the PA directly from the battery. Fully integrated MOSFET switches The 2MHz PWM operation of MIC2224 allows the smallest Constant 2MHz PWM operation possible components. It also allows the device to easily Internal soft-start meet stringent W-CDMA V response specifications. OUT 1% line and load regulation The MIC2224 operates from a 2.7V to 5.5V input, making <1A shutdown current it ideal for single cell Li-Ion applications. The device features built-in power MOSFETs that can supply up to Under-voltage lockout 600mA of output current in PWM mode, or over 1A in Thermal shutdown and current limit protection bypass mode. The MIC2224 can operate with a maximum 40C to +125C junction temperature range duty cycle of 100% for use in low-dropout conditions. The MIC2224 has a junction temperature range of Applications 40C to +125C and is available in a 10-pin 3mm x 3mm Cellular phones MLF package. PDAs Data sheets and support documentation can be found on Micrels web site at www.micrel.com. Typical Application L1 MIC2224 4.7H 5.4 V 2.6V to 5.5V V IN 2, 3 1 OUT V =4.2V IN 4.8 VIN SW 5 8, 9 4.2 AVIN VOUT Bypass 3.6 4 Mode C1 C2 ENABLE 1F 1F 3.0 6 DAC DAC 2.4 1.8 AGND PGND 1.2 710 GND GND 0.6 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2MHz PWM Converter with DAC Input V (V) DAC and 40m Bypass Switch MLF and MicroLeadFrame are registered trademarks or Amkor Technology, Inc. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC2224 (1) Ordering Information Part Number Output Junction Package Lead Finish Voltage Temp. Range MIC2224YML Adj. 40C to +125C 10-Pin 3mm x 3mm MLF Pb-Free Pin Configuration SW 1 10 PGND VIN 2 9 VOUT VIN 3 8 VOUT EN 4 7 AGND AVIN56EP DAC 10-Pin MLF (ML) Pin Description Pin Number Pin Name Pin Function 1 SW Switch (Output): Internal power MOSFET output switches. 2, 3 VIN Supply Voltage (Input): Requires bypass capacitor to GND. 4 EN A low level EN will power down the device, reducing the quiescent current to under 5A (typ 1A). 5 AVIN Supply Voltage (Input): Requires bypass capacitor to GND. 6 DAC DAC Control Input. Provides control of output voltage. The output voltage is 3 X the DAC voltage. (Ex. 0.5VDAC = 1.5V ). Bypass mode is enabled when the DAC OUT voltage exceeds 1.2V. 7 AGND Signal Ground of chip. 8, 9 VOUT Source of Internal P-Channel MOSFET and Feedback of internal PWM regulator. 10 PGND Power Ground of chip. EP Exposed Pad Connect to ground. M9999-091106 September 2006 2