Linear Technology Introduces Synchronous Step-Down DC/DC Controller

Photocoupler

Linear Technology Corporation has launched the LTC3869/-2, a dual-output high-efficiency synchronous step-down DC/DC controller that achieves up to 95% efficiency. This device is designed to deliver an excellent balance of current when operating in parallel channels. With a very low 2mV detection voltage, it ensures a maximum mismatch of less than ±4% between channels under both steady-state and transient conditions. The wide input voltage range of 4V to 38V makes it suitable for a variety of applications, including intermediate bus voltages and various battery chemistries.

The LTC3869/-2 features a powerful 1.1Ω internal gate driver that reduces switching losses, enabling high-power external MOSFETs to deliver up to 25A per channel from 0.6V to 12.5V. It maintains exceptional jitter-free performance even when the switching pulse edges span across phases, making it ideal for noise-sensitive environments. Applications include power supplies for ASICs and FPGAs, power distribution systems, network servers, and automotive power solutions.

Thanks to its current-mode control and a minimum turn-on time of just 90ns, the LTC3869/-2 is well-suited for high-frequency, high-step-down ratio applications where a compact design is required. The controller also supports tracking and sequencing, which helps optimize the power-up and power-down sequences for multiple power rails. It operates using full N-channel MOSFETs and provides output voltage accuracy of ±1% over a wide temperature range from -40°C to 125°C.

The output current can be sensed either by monitoring the voltage drop across the output inductor (DCR) for maximum efficiency or through a sense resistor. The fixed operating frequency can be set between 250kHz and 780kHz, or synchronized to an external clock via an internal PLL. Additional features include a built-in LDO for IC power, programmable soft-start, power-good signals, and external VCC control.

The LTC3869 is available in a 4mm x 5mm QFN package, while the LTC3869-2 comes in a SSOP-28 package. Both versions are pin-compatible with the LTC3850, offering flexibility for system designers. The unit price for 1,000 pieces is $2.65 each, and both variants are available in stock. Whether you're working on high-performance computing, industrial power systems, or automotive electronics, the LTC3869/-2 offers a reliable and efficient solution for your next project.