MILPITAS, CA - October 29, 2009 - Linear Technology announces the LTC3606B, a 2.25MHz, synchronous buck regulator with programmable average input current limit. It can deliver up to 800mA of continuous output current with efficiencies as high as 96%. Using a constant frequency and current mode architecture, the LTC3606B operates from an input voltage range of 2.5V to 5.5V, making it ideal for single-cell Li-Ion and USB applications. It can generate output voltages as low as 0.6V, enabling it to power the latest generation of low voltage DSPs and microcontrollers. The LTC3606B uses a switching frequency of 2.25MHz, allowing the use of tiny, low cost ceramic capacitors and inductors less than 1 mm in height. The combination of high switching frequency, tiny externals and a 3mm x 3mm DFN package make the LTC3606B a highly compact synchronous step-down solution.

The LTC3606B offers a programmable average input current limit that can be programmed between 200mA and 800mA, with ±5% accuracy via a single resistor. This makes the LTC3606B ideal for USB applications, supercapacitor charging and point-of-load power supplies. Combined with a supercapacitor, the LTC3606B enables its output to deliver high peak load currents of up to 2A without collapsing the input supply for applications such as GSM amplifiers. It also utilizes low dropout 100% duty cycle operation to allow output voltages equal to V_IN, further extending battery run time. The LTC3606B uses a pulse skipping mode to optimize light load efficiency while minimizing switching interference in applications that require the lowest possible noise. Other features include independent soft-start and power good indication, short-circuit protection and internal compensation. The LTC3606B is an ideal solution for handheld applications, which require input current limiting, outputs of up to 800mA, high efficiency and a very small solution footprint.

The LTC3606BEDD is available from stock in a 3mm x 3mm DFN-8. Pricing starts at $2.10 each for 1,000-piece quantities. An industrial grade version, the LTC3606BIDD, is tested and guaranteed to operate over a -40ºC to 125ºC operating junction temperature range and is priced at $2.47 each in 1,000-piece quantities. All versions are available from stock. For more information, visit www.linear.com.

Summary of Features: LTC3606B Programmable Average Input Current Limit: ±5% Accuracy Up to 96% Efficiency Very Low Noise Operation Input Voltage Range: 2.5V to 5.5V Output Voltage Range: 0.6V to 5V 2.25MHz Constant-Frequency Operation Power Good Output Voltage Monitor Low Dropout Operation: 100% Duty Cycle Internal Soft-Start Current Mode Operation for Excellent Line & Load Transient Response ±2% Output Voltage Accuracy Short-Circuit Protected Shutdown Current ≤ 1µA Available in Small 3mm × 3mm DFN Packages

800mA Synchronous Step-Down DC/DC Converter with Input Current Limit Click Photo for High-Res Image