Linear Technology Launches Step-Down DC/DC Controller with Wide Input Voltage Range
Operating junction temperature range of -55°C to 150°C

July 14, 2011 – Linear Technology Korea (CEO Hong Sa-kwak, www.linear.com ) announced the release of H and MP grade versions of its synchronous step-down DC/DC controller (product name: LTC3851A), which features a wide input voltage range (4V to 38V) suitable for a wide range of applications, including most intermediate bus voltages and chemical batteries. This powerful onboard MOSFET gate driver utilizes high-power external MOSFETs to generate up to 25A of output current over an output voltage range of 0.8V to 5.5V, making it ideal for point-of-load (POL) requirements. The performance of these H and MP grade versions is guaranteed through testing over operating junction temperature ranges of -40°C to 150°C and -55°C to 150°C, respectively. Key applications include automotive systems, industrial, medical, datacom, and telecom.

The constant frequency current mode architecture allows for a selection of fixed or phase-locked loop (PLL) frequencies ranging from 250 kHz to 750 kHz. Output current sensing can be achieved by measuring the voltage drop (DCR) at the output inductor or using an optional sensing resistor. Current foldback limits MOSFET heat dissipation during short circuits and overload conditions. Selectable continuous, pulse skip, or Burst Mode® operation can be user-controlled to optimize light-load efficiency. With a duty cycle of up to 99%, the LTC3851A/-1 provides a very low dropout voltage, a feature useful for extending operating time in battery-powered applications. Additional features include tracking and adjustable soft start. The difference between the LTC3851A-1 and the LTC3851A is that the LTC3851A-1 has a Power Good signal instead of an adjustable current limit.

The LTC3851AH/-1 and LTC3851AMP/-1 are available in a thermally enhanced MSOP-16 package. Pricing starts at $2.24 per unit for H-class devices and $5.29 per unit for MP-class devices, based on a 1,000-unit order. For more information, please refer to www.linear.com/product/LTC3851A .

Photo Caption: Step-down DC/DC controller with a dynamic temperature range of -55°C to 150°C

Product Features: LTC3851A/-1

• VIN in the range of 4V to 38V
• Powerful onboard N-channel MOSFET driver
• Current mode control
• DCR or RSENSE current sensing option
• Programmable current limit threshold voltage
• PLL synchronization
• Adjustable soft start or tracking
• Power Good Signal
• Fixed operating frequency or synchronizable in the 250kHz to 750kHz range