TC670ECHTR

Overview

The TC670ECHTR is a predictive fan failure detector manufactured by Microchip Technology. It operates within a supply voltage range of 3.0V to 5.5V and consumes a typical supply current of 90 µA. The device detects fan speed via the SENSE input, which has an internal resistance of 50 kΩ and a threshold voltage of 124 mV. The ALERT output is an open-drain digital signal capable of sinking 2.5 mA. The THRESHOLD pin accepts an analog input with a maximum voltage of 2.4 V and an input resistance of 100 MΩ. The CLEAR input resets the ALERT status. The component is housed in a 6-lead SOT-23 package and supports industrial temperature operation from -40°C to +85°C.

Feature Summary

• Predictive detection of fan wear-out for linear-controlled fans
• Configurable alert threshold using external resistor divider
• CLEAR capability to reset alerts and prevent false system shutdowns
• Low power consumption suitable for battery-operated systems

Applications

• Protection for linear-controlled fans
• Power supplies
• Industrial equipment
• PCs and notebooks
• Data storage and communications equipment

Procurement Notes

Verify that the ordering suffix CHTR corresponds to the tape and reel packaging format as specified in the product identification system. Confirm the E temperature grade matches the required industrial operating range of -40°C to +85°C. Ensure the 6-pin SOT-23 package dimensions align with the target PCB layout constraints. Cross-reference the datasheet revision D specifications against the specific manufacturing lot requirements.

Selection Notes

Select this component when monitoring linear-controlled 2-wire fans without requiring a dedicated tachometer wire. The device eliminates the need for 3-wire fan solutions by utilizing a sense resistor on the ground return leg. Consider the 124 mV input threshold at the SENSE pin when designing the sensing circuitry to avoid noise-induced false triggering. Evaluate the 90 µA typical supply current for low-power applications.

Part Context

The TC670ECHTR belongs to the TC670 family of tiny predictive fan failure detectors. It serves as a specialized integrated fan speed sensor designed to predict or detect fan failure, thereby preventing thermal damage to electronic systems. The device integrates frequency-to-voltage conversion logic internally to compare sensed fan pulses against a user-programmed threshold level.

Replacement Considerations

TC670ECH (Tube)

FAQ

How does the TC670ECHTR detect fan failure?

It senses voltage pulses generated by fan current flowing through a sense resistor. These pulses are converted to an analog voltage and compared against the DC voltage set at the THRESHOLD pin.

What is the function of the CLEAR input?

The CLEAR input allows the user to reset the ALERT pin status back to a high state, providing flexibility to connect with other system interrupts without initiating a shutdown due to false fault conditions.