LM93  Product Folder

The LM93, hardware monitor, has a two wire digital interface compatible with SMBus 2.0. Using an 8-bit [Sigma][Delta] ADC, the LM93 measures the temperature of two remote diode connected transistors as well as its own die and 16 power supply voltages.

To set fan speed, the LM93 has two PWM outputs that are each controlled by up to four temperature zones. The fan-control algorithm is lookup table based. The LM93 includes a digital filter that can be invoked to smooth temperature readings for better control of fan speed. The LM93 has four tachometer inputs to measure fan speed. Limit and status registers for all measured values are included.

The LM93 builds upon the functionality of previous motherboard management ASICs and uses some of the LM85's features (i.e. smart tachometer mode). It also adds measurement and control support for dynamic Vccp monitoring and PROCHOT#. It is designed to monitor a dual processor Xeon class motherboard with a minimum of external components.

• 8-bit [Sigma][Delta] ADC
• Monitors 16 power supplies
• Monitors 2 remote thermal diodes
• Internal ambient temperature sensing
• Programmable autonomous fan control based on temperature readings with fan boost support
• Fan control based on 13-step lookup table
• Temperature reading digital filter
• 1.0°C digital temperature sensor resolution
• 0.5°C temperature resolution for fan control
• 2 PWM fan speed control outputs
• 4 fan tachometer inputs
• Dual processor thermal throttling (PROCHOT#) monitoring
• Dual dynamic VID monitoring (6 VIDs per processor)
• 8 general purpose I/Os:
  • 4 can be configured as fan tachometer inputs
  • 2 can be configured to connect to THERMTRIP# from a processor
  • 2 are standard GPIOs that could be used to monitor IERR# signal
• 2 general purpose inputs that can be used to monitor SCSI termination signals
• Limit register comparisons of all monitored values
• 2-wire, SMBus 2.0 compliant, serial digital interface
  • Supports byte/block read and write
  • Configurable slave address (tri-level pin selects 1 of 3 possible addresses)
• 2.5V reference voltage output
• 56-pin TSSOP package
• XOR-tree test mode

• LM93 Operational	0°C to +85°C
  Remote Temp Accuracy	0°C to +125°C

• Servers
• Workstations
• Multi-Microprocessor based equipment