Part # LM94 datasheet

Part Manufacturer: National Semiconductor

National Semiconductor

Part Description: LM94 TruTherm• Hardware Monitor with PI Loop Fan Control for Server Management

Part Details:

LM94 May 2006 TruTherm LM94TruThermTM Hardware Monitor with PI Loop Fan Controlfor Server Management TM 1.0 General Description Hardware n 2 PWM fan speed control outputs n 4 fan tachometer inputs The LM94 hardware monitor has a two wire digital interface n Dual processor thermal throttling (PROCHOT) compatible with SMBus 2.0. Using a ADC, the LM94 monitoring measures the temperature of four remote diode connectedtransistors as well as its own die and 16 power supply n Dual dynamic VID monitoring (6/7 VIDs per processor) voltages. The LM94 has new TruTherm technology that sup- supports VRD10.2/11 ports precision thermal diode measurements of processors n 8 general purpose I/Os: Monitor on sub-micron processes. -- 4 can be configured as fan tachometer inputs-- 2 can be configured to connect to processor To set fan speed, the LM94 has two PWM outputs that are THERMTRIP each controlled by up to six temperature zones. The fan- -- 2 are standard GPIOs that could be used to monitor control algorithm can be based on a lookup table, PI IERR signal (proportional/integral) control loop, or a combination of both.The LM94 includes digital filters that can be invoked to n 2 general purpose inputs that can be used to monitor with smooth temperature readings for better control of fan speed the 7th VID signal for VRD11 such that acoustical noise is minimized. The LM94 has four n Limit register comparisons of all monitored values tachometer inputs to measure fan speed. Limit and status n 2-wire serial digital interface, SMBus 2.0 compliant PI registers for all measured values are included. -- Supports byte/block read and write The LM94 builds upon the functionality of previous mother- -- Selectable slave address (tri-level pin selects 1 of 3 Loop board server management ASICs, such as the LM93. It also possible addresses) adds measurement and control support for dynamic Vccp -- ALERT output supports interrupt or comparator monitoring for VRD10/11 and PROCHOT. It is designed to modes monitor a dual processor Xeon class motherboard with a n 2.5V reference voltage output Fan minimum of external components. n 56-pin TSSOP package n XOR-tree test mode

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LM94.pdf Datasheet