Dual Output Synchronous Step-Down DC/DC Controller Launched
Provides digital power system management functions via I2C/PMBus interface and onboard EEPROM

January 25, 2011 – Linear Technology Korea (CEO Hong Sa-kwak, www.linear.com ) announced the release of a high-efficiency dual-output synchronous step-down DC/DC controller (product name: LTC3880/-1) with an I2C-based PMBus interface for digital power system management. This device integrates analog switching regulator performance with precision mixed-signal data conversion for easy power system design and management, and is supported by the easy-to-use graphical user interface (GUI) LtpowerPlay software development system.

The LTC3880/-1 enables digital programming and readback for real-time control and monitoring of critical POL converter functions. Programmable control parameters include output voltage, gain and current limits, input and output monitoring limits, drive sequencing and tracking, switching frequency, and verifiable and traceable data. The on-chip precision data converter and EEPROM enable the capture and non-volatile storage of regulator settings and telemetry variables, as well as input/output voltage and current, duty cycle, temperature, and error logging.

The LTC3880/-1 can be configured to regulate two independent outputs or provide a single two-phase output. Additionally, it can be inserted and parallel-connected in up to six phases for precise sharing among multiple ICs, minimizing input/output filtering requirements for high-current and/or multi-output applications. The integrated amplifier provides full differential remote output voltage sensing, enabling high-accuracy regulation regardless of board IR voltage drop. The main applications of this product include high-current ASICs, telecom FPGAs and processor supplies, datacom, computing, and storage markets.

The LTC3880/-1 can be configured via the device's I2C serial interface using Linear Technology's LTpowerPlay GUI-based development software and can be easily stored in the internal EEPROM. The controller can operate independently with on-chip settings without burdening the host processor. The default settings allow for the free configuration of output voltage, switching frequency, phase, and device additions via an external resistor divider.

Designs can be easily calibrated and configured in firmware for single hardware design optimization for multiple applications. Since the converter loop gain does not change when power supply parameters are changed, compensation maintains an optimal state for multiple configurations.

The LTC3880 features a high-current integrated gate driver for driving all N-channel power MOSFETs from inputs ranging from 4.5V to 24V. It generates a maximum output current of 30A per phase across the entire operating temperature range and an accurate output voltage of ±0.50% in the 0.5V to 5.5V range. Maximum efficiency can be achieved through voltage DCR sensing for current sensing, or an external sensing resistor can be used freely. Programmable DCR temperature compensation can cancel the TC of the copper inductor to maintain accurate and continuous current limiting over a wide temperature range. The LTC3880/-1 features a minimum device on-time of 90 nanoseconds, making it ideal for ultra-small applications with high frequency and step-down ratios.

In addition, it can optimize the operation and stoppage of complex multi-rail systems by providing accurate timing in multiple chips and event-based squeezing. Additional features include constant frequency current mode control for cycle-to-cycle current limiting, configurable soft start, synchronizable switching frequency, and programmable GPIO pins that provide component status indication and self-recovery from errors.