Digital interface enables accurate telemetry from 13A-100A µModule regulator

July 01, 2015 // By Graham Prophet
Offering detailed system boot time and power analysis the LTM4676A is a dual 13A or single 26A µModule (“micromodule”) step-down DC/DC regulator with PMBus that supports current sharing up to 100A, with a serial digital interface.

The digital interface enables system designers and remote operators to command and supervise a system’s power condition and consumption. The regulator has 70 msec power-up time, 8 msec ADC telemetry update rate and 400 kHz PMBus-compliant I²C serial interface. These improvements allow quicker system boot time and faster data collection of power in applications with maximum power-up time requirements, such as PCIe-based platforms. Examples of end products are optical transport systems, datacom and telecom switches and routers, industrial test equipment, robotics, and RAID and enterprise systems where the cost of electrical utilities, cooling and maintenance are critical and must be continuously and precisely measured.

The LTM4676A contains EEPROM, power MOSFETs, inductors and supporting components. It has fast, dual analogue control loops, precision mixed signal circuitry and is housed in a 16 x 16 mm x 5.01 mm BGA (ball grid array) package.

In addition to delivering power to a point-of-load, the LTM4676A features configurability and telemetry monitoring of power and power management parameters over the PMBus I²C-based digital serial interface protocol. The LTM4676A operates from a 4.5V to 17V input supply and steps down V IN to two outputs ranging from 0.5V up to 5.4V. Two channels can current share to provide up to 26A (i.e., 13A + 13A as one output). Up to four LTM4676A devices can be multiphased to share current up to 100A output.

To evaluate the performance of the LTM4676A, the LTpowerPlay GUI (free to download), USB-to-PMBus converter and demo kit (DC1811B-KIT) are available. With ±0.5% maximum DC output error over temperature, ±2.5% current read back accuracy, integrated 16-bit delta-sigma ADC and EEPROM, the LTM4676A combines analogue switching regulator performance with precision mixed signal data acquisition. At start-up, output voltages, switching frequency and channel phase angle assignments can be set by pin-strapping resistors.

The LTM4676A internal operating temperature range is from -40°C to 125°C; it is priced at $33.95 (1000).

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