TPS40222

www.ti.com TPS40222 SLUS642A – OCTOBER 2005 – REVISED JANUARY 2006 1.6-A, 1.25-MHz BUCK CONVERTER IN A 3 mm × 3 mm SON PACKAGE FEATURES Input Voltage Range 4.5 VDC to 8 VDC Output Voltage (0.8 V to 90% VIN) 0 A to 1.6 A Current Capability Fixed 1.25-MHz Switching Frequency Reference 0.8 V ±1% Internal 250 mΩ N-Channel MOSFET Switch Current Mode Control with Internal Slope Compensation Internal Soft-Start Internal Loop Compensation Short Circuit Protection Thermal Shutdown High Efficiency Up to 92% Small 3 mm × 3 mm SON Package η − Efficiency − % 100 VIN = 5 V 95 TYPICAL EFFICIENCY vs LOAD CURRENT 90 85 VOUT = 3.3 V 80 75 70 VOUT = 1.25 V 65 APPLICATIONS Disk Drives Set Top Box Point of Load Power ASIC Power Supplies DESCRIPTION The TPS40222 is a fixed-frequency, current-mode, non-synchronous buck converter optimized for applications powered by a 5-V distributed source. With internally determined operating frequency, soft-start time, and control loop compensation, the TPS40222 provides many features with a minimum of external components. The TPS40222 operates at 1.25 MHz and supports up to 1.6-A output loads. The output voltage can be programmed to as low as 0.8 V. The TPS40222 utilizes pulse-by-pulse current limit as well as frequency foldback to protect the converter during a catastrophic short circuited output condition. SIMPLIFIED APPLICATION DIAGRAM VIN C1 6 5 4 BOOST AVIN PVIN TPS40222 FB GND SW 1 2 3 C2 L1 VOUT ...