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LM87 Checks Processor Temperature, Monitors Supply Voltages and Controls Fan Speeds in CPU-based Systems to Ensure Best Performance and Reliability

Nov 23, 1999

November 23, 1999 - National Semiconductor Corporation (NYSE:NSM) today announced the LM87 that remotely and internally monitors temperature, senses supply voltages and controls fan speed to ensure the best performance in higher-end PCs, servers and workstations.

Combining and enhancing the features of the popular LM81 and LM84, the new LM87 has: Eight positive voltage inputs for an eight-channel ADC to directly monitor power supplies, two fan-speed monitoring inputs, two-channel remote diode temperature sensing, on-chip temperature sensing and an eight-bit DAC to control fan speeds. The device also features a chassis intrusion detector and compatibility with SMBus(tm) and I2C(tm) serial interfaces, and VID/IRQ monitoring inputs for different CPU power supplies.

"The need to include system hardware monitoring on the motherboard has become extremely critical for manufacturers supplying corporate desktop PCs, servers and workstations," said Zaryab Hamavand, product marketing manager for National. "The LM87 is a highly integrated data acquisition system for hardware monitoring of virtually any microprocessor-based system. Its main advantage is that it takes all of the key analog and digital functions and monitors them with respect to system limits."

This integration allows system designers to efficiently implement a variety of monitoring functions and interrupts, saving board space and design time compared with using separate parts. The LM87 monitors supply voltages, temperatures and fan speeds within pre-set limits, generating interrupts when critical conditions are exceeded. Designers can input interrupt limits into a fully-programmable WATCHDOG? interrupt system. Besides SMBus and I2C compatibility, the LM87 also complies with the Advanced Configuration and Power Interface? (ACPI) power management specification.

Pricing and Availability
Available now, the LM87CIMT is priced at $2.80 each in 1K unit quantities. The device is housed in a space-saving 24-pin TSSOP package. For more information on the LM87, visit National's web site at www.national.com/appinfo/tempsensors.

About National Semiconductor
National Semiconductor provides system-on-a-chip solutions for the information age. Combining real-world analog and state-of the-art digital technology, the company's chips lead many sectors of the personal computer, communications, and consumer markets. With headquarters in Santa Clara, California, National reported sales of $2 billion for its last fiscal year and currently has about 11,000 employees worldwide. Additional company and product information is available on the World Wide Web at www.national.com.