March 31, 2015 – Linear Technology Korea (CEO Hong Sa-kwak) announced the launch of the LTC3887, a dual-output synchronous step-down DC/DC controller with an I2C-based PMBus interface suitable for digital power system management. The LTC3887 offers faster power-up time of 70ms and higher output voltage performance, while featuring an advanced function set including an 8ms update rate per parameter and high-speed ADC mode, differentiating it from the previously announced LTC3880. Additionally, the LTC3887 shares a common board footprint with the LTC3880. The LTC3887 integrates best-in-class analog switching regulator performance and precision mixed-signal data conversion capabilities for exceptionally easy power system design and management. The product is supported by the LTpowerPlay™ software development system featuring an easy-to-use GUI (graphical user interface).

The LTC3887 enables digital programming and read-back functionality for real-time control and monitoring of essential point-of-load (PoL) converter functions. Programmable control parameters include output voltage, margining and current limiting, input and output supervision limits, power-up sequencing and tracking, switching frequency, identification and traceability data. An on-chip precision data converter and EEPROM capture telemetry variables including regulator configuration, input and output voltage/current, duty cycle, temperature and fault logging, storing them non-volatilely.

The LTC3887 can regulate two independent outputs or be configured as two-phase single output. Up to six phases can be interleaved or paralleled across multiple ICs for precise current sharing. A highly integrated amplifier provides true differential remote output voltage sensing, achieving high-precision regulation independent of board IR voltage drop. Applications include high-current ASIC, FPGA and processor power supplies for telecom, datacom, computing and storage markets.

Configuration of the LTC3887 is easily stored in the internal EEPROM through the device's I2C interface using Linear Technology's LTpowerPlay GUI-based development software. Thanks to on-chip stored configuration, the controller can power up automatically without burdening the host processor. Default settings can be optionally configured with external resistor dividers suitable for output voltage, switching frequency, phase and device address. Since firmware allows easy compensation of various designs for configuration, a single hardware design can be optimized for diverse applications. As power supply parameters change, the converter loop gain does not change. Therefore, compensation remains optimal for various configurations.

The LTC3887 features high-current, highly integrated gate drivers to drive all N-channel power MOSFETs across an input voltage range of 4.5V to 24V. The product generates precision output voltage of ±0.50% across a 0.5V to 5.5V range using output current up to 30A per phase across the full operating temperature range. Best-in-class efficiency is achieved by sensing voltage drop across the DCR (output inductor) for current sensing, or external sense resistor can optionally be used. Programmable DCR temperature compensation cancels the temperature coefficient of copper inductors to maintain accurate and stable current limiting across a wide temperature range.

With a minimum on-time of only 90nsec, the LTC3887 is ideal for compact, high-frequency/high step-down ratio applications. Precise timing across multiple chips and event-based sequencing can optimize power-up and power-down of complex multi-rail systems. Additional features include fixed-frequency current-mode control with cycle-by-cycle current limiting, adjustable soft-start, synchronizable switching frequency, and programmable GPIOs that indicate device status and provide automatic recovery from default.

The LTC3887 is available in a 40-pin 6mm x 6mm QFN package operating over a junction temperature range of –40ºC to 125ºC. It is offered at $5.47 per unit based on 1,000-unit quantity. For more information, refer to www.linear.com/product/LTC3887.

I2C/PMBus Dual Synchronous Step-Down DC/DC Controller

Product Features: LTC3887

• Dual-output synchronous DC/DC controller

• Powerful on-board N-channel MOSFET driver

• I2C/PMBus-compatible serial interface

• Integrated non-volatile EEPROM memory

• Programmable parameters include VOUT, ILIM, sequencing, margining, OV/UV levels & switching frequency

• System management telemetry variables include VIN, IIN, VOUT, IOUT, duty cycle, temperature & fault status logging

• VIN range: 4.5V to 24V

• VOUT range: 0.5V to 5.5V

• ±0.5%: Maximum DC output voltage error across full operating junction temperature range

• 70ms power-up time

• High-speed ADC mode updates selectable parameters once every 8ms

• Temperature-compensated DCR or RSENSE current sensing

• PolyPhase® for up to six-phase operation

• Fixed frequency with phase-lock capability ranging from 250kHz to 1MHz

USA list pricing information is for approximate budgeting purposes, and international pricing may vary depending on regional tariffs, taxes, fees and exchange rates.