January 8, 2013 – Linear Technology Korea (CEO Hong Sa-kwak) announced the launch of a synchronous buck converter (product name: LTC3646) capable of handling a 40V input. This product can provide a continuous output current of up to 1A in a 3mm x 4mm DFN-14 (or thermally enhanced MSOP16) package. Operating over an input voltage range of 4V to 40V, it is ideal for automotive and industrial applications requiring high-voltage input performance, high efficiency, and high-speed switching frequencies, targeting a small solution footprint.

The LTC3646 utilizes a proprietary controlled on-time architecture capable of stepping down from 36V to 3.3V even when the switching frequency is set above 2MHz, ensuring that switching noise does not affect critical frequency bands such as AM radio. Furthermore, it can provide a very fast transient response even at duty cycles of less than 10%. The built-in synchronous rectification offers high efficiency of 95% and requires only 140µA of standby current, maximizing battery operating time. The combination of a 3mm x 4mm DFN package (or MSOP-16E) and small external components provides a very compact solution footprint for a wide range of high-voltage applications.

The LTC3646 provides a high-efficiency output of up to 1A using an integrated high-side and synchronous power switch. The built-in switching frequency can be programmed between 200kHz and 3.0MHz or synchronized with an external clock. The combination of high efficiency and a standby current of only 140µA achieves high efficiency characteristics over a very wide load range. For noise-sensitive applications, the LTC3646 can be used in a forced continuous operation mode to minimize voltage ripple.

The standard LTC3646 provides an output range of 2.0V to 30V, while the LTC3646-1 provides an output of 0.6V to 15V. Both versions offer additional features, including built-in soft start, built-in compensation circuitry, and robust short-circuit protection.

The LTC3646EDE/-1 and LTC3646EMSE/-1 are available for $2.85 each for two packages. The extended temperature versions (Rate I), the LTC3646IDE/-1 and LTC3646IMSE/-1, are supplied for $3.14 each. Finally, the high temperature (Rate H) options, the LTC3646HDE/-1 and LTC3646HMSE/-1, are available for $3.39 each. All prices are based on a quantity of 1,000, and all versions are available immediately.

For details, refer to www.linear.com/product/LTC3646. Photo caption : 40V, 1A synchronous buck converter providing 95% efficiency.

Product Features: LTC3646/-1
• Wide input voltage range: 4.0V ~ 40V (absolute maximum of 45V)
• 1A output current guarantee
• High efficiency: Up to 95%
• Wide output voltage range
o LTC3646: 2.0V ~ 30V
o LTC3646-1: 0.6V ~ 15V
• 2 MHz constant frequency operation at a minimum 6% duty cycle
• +1% accurate reference voltage
• Internal or external compensation
• Adjustable switching frequency & synchronization range: 200kHz ~ 3MHz
• Selectable High-Efficiency Burst® Operation or Forced Continuous Mode
• 14-pin 3mm × 4mm DFN or thermally enhanced 16-pin MSOP package