General Description
The TC670 is an integrated fan speed sensor that predicts and/or detects fan failure, preventing thermal damage to systems with cooling fans. When the fan speed falls below a user-specified level, the TC670 asserts an ALERT signal. With this design, a critical minimum fan speed is determined by the user. The fan alert level is then set with a resistor divider on the THRESHOLD pin (Pin 1) of the TC670. When the minimum fan speed is reached, the ALERT pin (Pin 5) changes from a digital high to low. This failure detection works with all linear-controlled 2-wire fans. The TC670 eliminates the need for 3-wire fan solutions.

FEATUREs
• Fan Wear-Out Detection for 2-Wire Linear-Controlled Fans
• Replacement System for 3-Wire Fans
• Fan Alert Signal when Fan Speed is below Programmed Threshold
• CLEAR Capability for Eliminating False Alarm
• Low Operating Current, 90 µA (typ.)
• VDD Range 3.0V to 5.5V
• Available in a 6-Pin SOT-23 Package

APPLICATIONs
• Protection for Linear-Controlled Fans
• Power Supplies
• Industrial Equipment
• PCs and Notebooks
• Data Storage
• Data Communications Equipment
• Instrumentation