ACT4088

Rev PrA, 24-Jul-07 Advanced Product Information – All Information Subject to Change ACT4088 28V, 1.5A, 1.4MHz Step-Down DC/DC Converter in SOT23-6 FEATURES            Wide 4.5V to 28V Input Voltage Range 1.5A Output Current (12VIN to 5VOUT) Output Adjustable Down to 0.81V 0.3Ω Internal Power MOSFET Up to 92% Efficiency Stable with Low ESR Ceramic Output Capacitors Fixed 1.4MHz Operating Frequency Internal Soft-Start Function Over Current Protection with Hiccup-Mode Thermal Shutdown Available in a SOT23-6 Package GENERAL DESCRIPTION The ACT4088 is a current-mode step-down DC/DC converter that supplies up to 1.5A into 5V from a 12V input. 1.4MHz switching frequency allows the use of tiny external components, and internal loop compensation provides simple, stable power supplies with a minimum of external components. Optimized for use with ceramic input and output capacitors, the ACT4088 provides a very compact 1.5A power supply for space constrained mobile and consumer applications. The ACT4088 operates over a wide input voltage range and utilizes current-mode operation to provide excellent line and load transient response while requiring no external compensation components. Fault protection includes cycle-by-cycle current limiting, frequency fold-back, hiccup mode, and thermal shutdown. Internal soft-start provides a controlled startup with no overshoot, even at light loads. The ACT4088 is available in a tiny SOT23-6 package and requires very few external componen...