Current Mode Control, Sub-milliohm DCR Sensing, I2C/PMBus Interface & Programmable Loop Compensation Function

Linear Technology Korea (CEO Hong Sa-kwak) announced the launch of a dual-output current-mode synchronous step-down DC/DC controller (product name: LTC3884) featuring programmable loop compensation and I2C-based PMBus interface.

This device improves the signal-to-noise ratio of the current sensing signal to enable the use of very low DCR power inductors (0.3 milliohm), maximizing converter efficiency and increasing power density.

The LTC3884 operates over an input voltage range of 4.5V to 38V and generates output voltages up to 5.5V. Up to 6 phases can be arranged in parallel, and by clocking the phases differently, input and output filtering can be minimized. When two outputs are connected in parallel, the LTC3884 provides current mismatch of less than ±5% between phases.

Uses Very Low DCR Power Inductor (0.3 milliohm)

Alternatively, the LTC3884 can be used with the LTC3874 phase extender, making it ideal for high current requirements up to 240A. An on-board differential amplifier provides remote output voltage sensing for both outputs. Applications include power distribution, redundant (n+1) power supplies, FPGA, ASIC, and processor power.

The LTC3884 can select a fixed operating frequency in the range of 200kHz to 1MHz or can be synchronized to an external clock. Robust 1.1Ω on-board all N-channel gate drivers minimize MOSFET switching losses.

The LTC3884's adjustable precision current limit threshold can be configured for very low sense voltages in the range of 10mV to 30mV, further reducing power loss. Additional features include input current sensing, two power good output signals, programmable soft start, and programmable fault recovery techniques.

The LTC3884 is supported by the GUI-based LTpowerPlay™ software development tool. Through a serial I2C-based interface, system designers and telecom operators can command and monitor the system's power conditions and consumption. The ability to digitally change power supply parameters shortens time-to-market and system down time, and eliminates situations requiring physical hardware, circuit, or system BOM changes. The LTC3884 simplifies system characterization, optimization, and data mining during prototyping, deployment, and field operation periods.

Beyond supplying power to the point-of-load (PoL), the LTC3884 provides configuration and telemetry functions for monitoring power and power management elements in PMBus, an open standard I²C-based digital serial interface protocol.

Through the LTC3884's two-wire serial interface, the output can be margined, regulated, and rise and fall with programmed slopes at successive delay times. Input and output voltage, current, and temperature readings are available. This device is composed of a fast analog control loop and precision mixed-signal circuits and EEPROM, and is packaged in a 7mm x 7mm QFN-48 package.

To evaluate the performance of the LTC3884, the LTpowerPlay GUI can be downloaded and used free of charge. A USB-to-PMBus converter and demo kit are also available. With features including ±0.5% maximum DC output error over the full operating temperature range, ±1.5% current readback accuracy, high-integration 16-bit delta-sigma ADC, and EEPROM, the LTC3884 integrates industry-leading analog switching regulator performance and precision mixed-signal data acquisition with non-volatile fault logging capabilities.

Channels can accurately share current in both steady-state and transient conditions. During operation, output voltage switching frequency and channel phase adjustment can be set by pin-strapping resistors or loaded from the embedded EEPROM. Priced at $6.35 per unit based on 1,000-unit quantities.