Linear Technology announces new synchronous step-down DC-DC controller

Date
09/16/2012

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LTC3883/-1 combines current-mode switching-regulator performance with precision mixed-signal data acquisition

Click image to enlarge: Linear Technology LTC3883.

Linear Technology's new LTC3883/-1, synchronous step-down DC-DC controller comes with an I2C-based PMBus interface for managing digital power systems. The device combines current-mode switching-regulator performance with precision mixed-signal data acquisition for unsurpassed ease of power-system design and management. The controller is supported by the LTpowerPlay software-development system through an easy-to-use graphical user interface (GUI). The LTC3883 allows for digital programming and read back for real-time control and monitoring of critical point-of-load converter functions. Programmable control parameters include output voltage, margining, and current limits, input and output supervisory limits, switching frequency and tracking. On-chip precision data converters and EEPROM enable capture and nonvolatile storage of regulator-configuration settings and telemetry variables, including input voltage and current, output voltage and current, duty cycle, temperature, and fault logging. Configurations for the LTC3883 are easily saved to the internal EEPROM over the device's I2C serial interface, using Linear Technology's LTpowerPlay GUI-based development software. With configurations stored on-chip, the controller can power-up autonomously without burdening the host processor. Default settings can be optionally configured by external resistor dividers for output voltage, switching frequency, phase, and device address. Multiple designs can be easily calibrated and configured in firmware to optimize a single hardware design for a range of applications. The LTC3883 can be configured for up to 6 phases that can be interleaved and paralleled for accurate sharing among multiple ICs, minimizing input and output filtering requirements for high current and multiple output requirements. Applications include high current ASIC, FPGA, and processor supplies in telecom, datacom, computing, and storage markets. The LTC3883 features high-current integrated gate drivers to drive N-channel power MOSFETs from input voltages ranging from 4.5V to 24V. It can produce 0.5% accurate output voltages from 0.5V to 5.5V with output currents up to 30 A per phase over the full operating temperature range. An integrated amplifier provides true differential remote output-voltage sensing, enabling high accuracy regulation, independent of board IR voltage drops. Highest efficiency is achieved by sensing current using the voltage drop across the output inductor (DCR), or an external sense resistor can be optionally used. Programmable DCR temperature compensation maintains an accurate and constant current limit over a broad temperature range. The device's minimum on-time of just 90 ns makes the LTC3883/-1 well suited for compact high-frequency, high step-down-ratio applications. Accurate timing across multiple chips and event-based or time-based sequencing allow the optimization of power-up and power-down of complex, multiple rail systems. Additional features include storage of identification and traceability data, cycle-by-cycle current limit, adjustable soft start, a synchronizable switching frequency, and programmable GPIO pins to indicate part status and to provide autonomous recovery from faults. The LTC3883 features an onboard LDO for controller and gate-drive power, and the LTC3883-1 allows for an external bias voltage for highest efficiency. Both parts are available in a thermally enhanced 5 x 5 mm QFN-32 package. The extended temperature range grade is specified over a -40 to 105 °C operating junction temperature range. The industrial grade part is specified over a -40 to 125 °C operating junction temperature range. Pricing starts at $4.82 each in 1000-piece quantities and both versions are available from stock. Linear Technology LTC3883 product deeplink

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