Milpitas, Calif—"Digital power" is a hot topic, and can take two forms: an all-digital control/regulation loop, or a more-conventional analog closed loop but supplemented with digital control of key setpoints and parameters. The LTC3880 falls into the latter camp, providing a dual-output synchronous DC/DC controller combined with digital management via the I2C/PMBus and internal EEPROM.
This allows users to program, change, and monitor power-control performance in real time, using a GUI-based development package which the vendor also provides. Target applications include point-of-load (PoL) converters for high-end, higher-power situations, such as datacom/telecom centers, networking, storage centers, and medical/industrial systems.
The basic controller provides a polyphase (up to six phases can be controlled in conjunction with multiple ICs) step-down control with an input voltage range of 4.5 to 24V and output range of 9.5 to 5.5V, with ±5% output voltage accuracy over the operating temperature range, and the controller includes a differential amplifier to enhance remote output-voltage sensing. Efficiency can be as high as 92% for this IC, which also includes N-channel gate drivers for the user-supplied external MOSFETs.
Using the digital interface, the user can set the output voltage; start-up characteristics including sequencing, tracking, timing delays, and ramp up/ramp down; protection aspects such as under/overvoltage and current limits; actions to be taken when faults occur; margining; and switching frequency.
In the reporting direction, the controller can report input and output voltage and current; faults; historical record; and more. Key set-up and operating data is stored in internal EEPROM, and digital interface is via I2C, PMBus, VID (voltage ID), and other protocols. An internal low dropout regulator (LDO) supports the controller and gate-driver power circuitry; the LTC3880-1 variant allows the user to provide an external bias voltage to improve efficiency.
Pricing, packaging, and availability: The LTC3880 and LTC3880-1 are available now, and are offered in a thermally enhanced 6 x 6 mm QFN-40 package, in several temperature ranges, up to -40°C to +125°C. Pricing starts at $5.35 each, in 1000-part lots.
For more information, go to http://www.linear.com/3880.