Linear Technology Launches Dual Output Synchronous DC/DC Controller
Provides excellent channel-to-channel current sharing, boosting power, and reliability.

March 14, 2011 – Linear Technology Korea (CEO Hong Sa-kwak, www.linear.com ) announced the release of the dual-output, high-efficiency (up to 95%) synchronous step-down DC/DC controller (LTC3869/-2), which provides highly balanced current sharing between channels in parallel connection. Due to its low sensing voltage maximum mismatch of 2mV, this controller can maintain a current mismatch of +/-4% or less between channels during sustained and transient conditions when the two outputs are connected in parallel. The device offers an input range of 4V to 38V and can be used in a wide variety of applications, including most intermediate bus voltages and battery applications. A powerful 1.1Ω onboard gate driver minimizes switching losses, enabling the use of high-power external MOSFETs to generate up to 25A of output current per channel, along with an output voltage range of 0.6V to 12.5V. This device maintains excellent jitter attenuation performance even during phase-to-phase switching edge crossings, making it ideal for use in requirements that are particularly sensitive to noise. Key applications include ASIC and FPGA supplies, power distribution, network servers, and automotive power systems.

The LTC3869/-2 is ideal for high-frequency applications with high step-down ratios where a small solution size is required, thanks to its self-contained current mode control and a minimum on-time of 90ns. Tracking and sequencing functions optimize the driving and stopping of multiple power rails. This device operates with all N-channel MOSFETs and generates output voltages with ±1% accuracy over a wide operating temperature range of -40°C to 125°C. The output current is sensed via voltage drop-over-output (DCR) monitoring or through the use of a sensing resistor to provide high efficiency. The fixed operating frequency is programmable in the range of 250 kHz to 780 kHz, or can be synchronized with an external clock of the internal phase-locked loop (PLL). Additional features include an onboard LDO for IC power, programmable soft start, a power good signal, and external VCC control.

The LTC3869 is pin-compatible with the LTC3850 in both package options. The LTC3869 is currently available in a 4mm x 5mm QFN package, while the LTC3869-2 is available in SSOP-28. Pricing starts at $2.65 per unit for orders of 1,000.