PMBus Power System Manager Controls & Monitors 16 Power Supplies to ±0.25% Voltage Accuracy

The LTM2987 is a 16-channel Power System Manager used to sequence, trim (servo), margin, supervise, manage faults, provide telemetry and create fault logs. PMBus commands support power supply sequencing, precision point-of-load voltage adjustment and margining. DACs use a proprietary soft-connect algorithm to minimize supply disturbances. Supervisory functions include overvoltage and undervoltage threshold limits for sixteen power supply output channels and two power supply input channels, as well as over and under temperature limits. In conjunction with Arrow Electronics Ltd.

The LTM2987 from Linear Technology is a highly integrated 16-channel µModule® PMBus power system manager, which adds extensive digital control and monitoring to an analog power system. Software-based configuration and measurement of power system performance reduces time to market, enhances system reliability and enables finely optimized board energy consumption.

The device trims, margins and monitors supply outputs with best-in-class ±0.25% voltage accuracy, raising circuit board yields and long-term reliability. Supply sequencing (timed and tracking), supervision and EEPROM fault-logging are also built in while all basic passive components, low pass RC filters, bypass capacitance and pull-up resistors, are fully integrated.

The high functional and component integration reduces solution footprint, shortens the bill of materials and eases routing on large rail-count ASIC, DSP and FPGA boards in servers, network routers and industrial test equipment.

A 16-bit ADC in the LTM2987 measures supply output voltages, input voltage and device temperature. Fast under and overvoltage supervisors prevent system malfunction and damage. Faults trigger EEPROM black box recording, which simplifies failure analysis while providing insight into future system improvements.

Programmable fault responses can disable the power supplies with optional retry after a fault is detected. Faults that disable a power supply can automatically trigger black box EEPROM storage of fault status and associated telemetry. The internal 16-bit ADC monitors sixteen output voltages, two input voltages, and die temperature. In addition, odd numbered channels can be configured to measure the voltage across a current sense resistor.

A programmable watchdog timer monitors microprocessor activity for a stalled condition and resets the microprocessor if necessary. A single wire bus synchronizes power supplies across multiple LTC Power System Management (PSM) devices. Configuration EEPROM supports autonomous operation without additional software.

Multiple Power System Managers can be cascaded to sequence and fault-manage more than 16 rails. Over one hundred PMBus compatible commands are provided for flexible programming and data readback of the power system.

Register configuration is accomplished through the LTpowerPlay™ development environment, which supports all Linear Technology digital Power System Management (PSM) devices. Once programmed, no software coding is needed for autonomous operation.

Specified over the 0°C to 70°C commercial and -40°C to 105°C industrial temperature range, the LTM2987 is offered in a 144-pin 15mm x 15mm BGA (ball grid array) package. 1,000-piece pricing starts at $23.95 each. Device samples and evaluation circuit boards are available online or from your local Linear Technology sales office.

Typical applications include computers and network servers, industrial test and measurement, high reliability systems, medical imaging and video.

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