Electronic Design

DC/DC Controller Adds PWM Signals for Digital Power System Management

Linear Technology introduced the LTC3887-1, a dual-output synchronous step-down dc/dc controller. Unlike the LTC3887 that was released earlier this year, the new controller includes pulse-width modulation to drive power blocks or stages. It is designed for FPGAs and other high-current processors used in communications.

The LTC3887-1 supports a power management bus serial interface for digital power management, which enables it to function as a development tool for high-current systems. Equipped with external configuration resistors, it is capable of programming a wide range of control parameters, including output voltage and switching frequency.

This ensures accurate and constant-current limit within complex, multiple-output systems. These configurations are captured using the digital interface or stored in nonvolatile EEPROM memory, providing data characterizations throughout the design or management process. 

The LTC3887-1 features a 70-ms power-up time and analog-to-digital converter (ADC) mode that provides an 8-ms update rate for a single system parameter. In the standard configuration, the device regulates two independent outputs, but it can also support a two-phase single output from 0.5V to 5.5V.

For accurate sharing of information over multiple integrated circuits, the controller can interleave and parallel up to six phases, while minimizing input and output filtering requirements. In addition, the device is compatible with LTpowerPlay development software with a graphical user interface (GUI).

Operating over 4.5V to 24V input voltage range, the LTC3887-1 produces ±0.50% accurate output voltages from 0.5V to 5.5V with output current up to 40A per phase over the full operating temperature. An integrated power amplifier provides true differential remote output voltage setting. This enables high-accuracy regulation in spite of board IR voltage drops. The full data sheet is available from Linear Technology.

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