Buck converter delivers high efficiency in a small package

By Gina Roos, editor-in-chief

Analog Devices Inc. (ADI) introduced the Power by Linear LTC3310S , a 5-V, 10-A low-EMI monolithic synchronous buck converter that uses the company’s Silent Switcher 2 architecture with integrated hot loop bypass capacitors. The result: a highly efficient and small buck converter at frequencies up to 5 MHz with excellent EMI performance.

The fixed-frequency peak-current mode architecture of the device is well-suited for high-stepdown-ratio applications that require fast transient response, according to ADI. Another key feature is the multiphase operation that enables direct paralleling of multiple devices for higher current.

Thanks to a wide voltage input range of 2.25 V to 5.5 V, the LTC3310S can be used in a variety of applications, including most intermediate bus voltages. Integrated low on-resistance MOSFETs provide continuous load currents as high as 10 A with minimal thermal derating, and output voltages ranging from 0.5 V to VIN make the devices suited for point-of-load applications such as high-current/low-voltage DSP/FPGA/GPU/ASIC reference designs. Other key applications include optical networking, telecom/datacom and automotive systems, distributed power architectures, and general medium- to high-power-density systems.

The device’s low 35-ns minimum on-time enables a high-stepdown-ratio power supply at high frequency, and 100% duty cycle operation delivers low dropout performance. The operating frequency can be synchronized to an external clock, said ADI. The total reference voltage accuracy is ±1% over the –40°C to 125°C operating junction temperature range.

Key specs:

• High efficiency: 4.5-mΩ NMOS and 16-mΩ PMOS
• VIN range: 2.25 V to 5.5 V
• VOUT range: 0.5 V to VIN
• VOUT accuracy: ±1%
• 35-ns minimum on-time
• Programmable frequency to 5 MHz
• Shutdown current: 1 µA
• Precision 400-mV enable threshold

Other features include a power good signal when the output is in regulation, precision enable threshold, output overvoltage protection, thermal shutdown, die temperature monitor, clock synchronization, mode selection, and output short-circuit protection.

The LTC3310S is available in a thermally enhanced 18-lead 3 × 3 × 0.94-mm LQFN package. The E- and I- grades are specified from –40°C to 125°C operating junction temperature range. Available from stock, pricing for the LTC3310S starts at $2.60.