National Semiconductor Introduces Industry’s First PMBus System Power Management and Protection IC

National’s LM25066 integrates high-performance monitoring, protection and control blocks that precisely control and manage the electrical operating conditions of each blade in the chassis. It also provides accurate monitoring of critical system power consumption and fault conditions.

The LM25066 continuously supplies the system management host with real-time power, voltage, current, temperature and fault data for each blade subsystem. The LM25066’s system management bus (SMBus) communications interface delivers this data using the PMBus protocol. The host’s system diagnostic and optimization routines use the data to increase system reliability and minimize the data center’s total power consumption.

Key Features - LM25066 PMBus System Power Management and Protection IC

The LM25066 features a voltage input range of 2.9V to 17V and a selectable 25 mV/50 mV current limit threshold for addressing a wide range of intermediate bus voltages and load currents. The LM25066 monitoring block measures both current and voltage at 1,000 times per second with a current measurement accuracy of three percent over the full temperature range of -40 degrees C to 125 degrees C. Additionally, its simultaneous sampling of current and voltage provides a true power measurement of the server blade power consumption. The monitoring block also captures the peak current and peak power and computes the average of subsystem operating parameters (Vin, Iin, Pin and Vout).

A temperature monitoring block on the LM25066 interfaces with a low-cost external diode for monitoring the temperature of the external MOSFET or other critical temperature source. The LM25066 reports the status of all system parameters and fault conditions through the SMBus interface and offers individually programmable warning thresholds for all faults. This feature provides design flexibility and dynamic system protection.

The LM25066 control and protection blocks include National’s unique hot-swap architecture that provides both current and power limiting to protect sensitive circuitry during insertion of boards from a live system backplane or any other hot power source. The LM25066 protection block also provides adjustable under/overvoltage and hysteresis.

National supports the LM25066 with a suite of powerful development tools that simplify application design and system verification. System designers may also use these tools to create value-added features for their subsystems.