DESCRIPTION
The LTC®1695 fan speed controller provides all the functions necessary for a power management microprocessor to regulate the speed of a 5V brushless DC fan via a 2-wire SMBus/I2C interface. Fan speed is controlled according to the system’s required temperature profile and permits lower fan power consumption, longer battery run time and lower acoustical generated noise versus systems that only provide simple on-off control for the fan.

FEATURES
■ Complete SMBus/I2CTM Brushless DC Fan Speed Control System in a 5-Pin SOT-23 package
■ 0.75Ω PMOS Linear Regulator with 180mA Output Current Rating
■ 0V to 4.922V Output Voltage Range Controlled by a 6-Bit DAC
■ Simple 2-Wire SMBus/I2C Interface
■ 250ms Internal Timer Ensures Fan Start-Up
■ Current Limit and Thermal Shutdown
■ Fault Status Indication via SMBus Host Readback

APPLICATIONS
■ Notebook Computers
■ Spot Cooling
■ Portable Instruments
■ Battery-Powered Systems
■ DC Motor Control
■ White LED Power Supplies
■ Programmable Low Dropout Regulator