TC670ECHTR.

The TC670ECHTR is an integrated Fan Speed Sensor predicts or detects fan failure, preventing thermal damage to systems with cooling fans. When the fan speed falls below 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. A CLEAR option can be used to reset the ALERT signal, allowing the flexibility of connecting the ALERT output of the TC670 with other ALERT/FAULT interrupts in the system. This feature can be implemented so that false fan fault conditions do not initiate system shutdown.

• 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
• 90µA Typical low operating current