Low-EMI synchronous buck converter suits high-power-density applications that require fast transient response

By Gina Roos,

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.