GENERAL DESCRIPTION
The ADM1028 is a low-cost temperature monitor and fan controller for microprocessor-based systems. The temperature of a remote sensor diode may be measured, allowing monitoring of processor temperature in single processor systems. An on-chip temperature sensor monitors ambient system temperature.
Measured values can be read out via the System Management Bus, and values for limit comparisons can be programmed in over the same serial bus.
The ADM1028 also contains a DAC for fan speed control. An automatic hardware temperature trip point is provided and the fan will be driven to full speed if it is exceeded. A Ramp Rate Register is provided to control the rate with which fan speed is increased or decreased. This is to eliminate sudden changes in fan speed, thereby reducing fan acoustics and prolonging the fan’s life.

FEATURES
  On-Chip Temperature Sensor
  External Temperature Measurement with Remote Diode
  Interrupt and Over-Temperature Outputs
  Fault-Tolerant Fan Control with Auto Hardware Trip Point
  Remote Reset and Power-Down Functions
  LDCM Support
  System Management Bus (SMBus) Communications
  Standby Mode to Minimize Power Consumption
  Limit Comparison of all Monitored Values
  DAC Output for Linear Fan Speed Control
  Ramp Rate Register for Control of Rate of Change of Fan Speed, Reduction of Fan Acoustics

APPLICATIONS
  Network Servers and Personal Computers
  Microprocessor-Based Office Equipment
  Test Equipment and Measuring Instruments