Microchip Technology MIC2224YML

Description
The MIC2224 is a high-efficiency 2MHz PWM synchronous buck switching regulator designed for powering 2.5G and 3G CDMA RF Power Amplifiers. Its output voltage can be dynamically adjusted with an external DAC to optimize PA efficiency based on required output power. When the PA demands maximum power, the DAC can activate a low on-resistance, 40mΩ bypass switch, connecting the PA directly to the battery.
The 2MHz PWM operation enables the use of smaller components and facilitates compliance with stringent W-CDMA Vout response specifications. The MIC2224 operates within a 2.7V to 5.5V input range, making it suitable for single-cell Li-ion applications. It features integrated power MOSFETs capable of delivering up to 600mA of output current in PWM mode or over 1A in bypass mode. The device can operate with a maximum duty cycle of 100% for low-dropout conditions.

Features
Input voltage range: 2.7V to 5.5V
DAC-adjustable output voltage down to 0.3V
600mA output current in PWM mode
Internally protected 40mΩ bypass switch
Direct battery-to-load connection capability
Over 95% efficiency
Fully integrated MOSFET switches
Constant 2MHz PWM operation
Internal soft-start
1% line and load regulation
<1μA shutdown current
Under-voltage lockout
Thermal shutdown and current limit protection
Junction temperature range: -40°C to 125°C

Applications
Cellular phones
PDAs