Hardware Hacking

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 of the TC670. When the minimum fan speed is reached, the ALERT pin 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. The TC670 is specified to operate over the full industrial temperature range of -40°C to 85°C. The TC670 is offered in a SOT23-6 pin package and consumes 90uA (typ) during operation. The space saving package and low power consumption make this device an ideal choice for systems requiring fan speed monitoring. 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. The TC670 is a predictive fan failure detector that asserts a signal whenever the fan’s RPM falls below a user-programmable RPM level.
TC670 Vendor
Microchip
TC670 Categories
Fan Controllers

Parameter Value
Description Fan Manager
Typical Accuracy (°C) N/A
Maximum Accuracy @ 25°C N/A
Maximum Temperature Range (°C) -40 to +85
Vcc Range (V) +3.0 to +5.5
Max. Supply Current (µA) 150

The TC655 is a dual PWM mode fan speed controller with FanSense TM technology for use with brush-less DC motors. The device allows temperature proportional speed control and therefore accomplishes lower acoustic fan noise and longer fan life. The TC655 reads the voltage provided by an external ther-mistor (or voltage output temperature sensor) and adjusts a 30% to 100% PWM duty cycle output to the fan with respect to the input temperature voltage. The PWM duty cycle can also be programmed via SMBus to allow fan speed control without the need of an external thermistor.In normal fan operation, pulse trains are present at the SENSE pin. These pulses are used to calculate the fan RPM. The fan RPM data is used to detect a worn out, stalled, open or unconnected fan. An RPM level below the user-programmable threshold causes the TC655 to assert a logic low alert signal (FAULT). Thedefault value is 500RPM. The TC655 consumes only 0.3mA during operation and can also enter a low-power shutdown mode by setting the appropriate bit in the configuration register.
TC655 Vendor
Microchip
TC655 Categories
Fan Controllers

Parameter Value
Typical Accuracy (°C) Depends on external thermistor
Maximum Accuracy @ 25°C Depends on external thermistor
Maximum Temperature Range (°C) -40 to +85
Vcc Range (V) +3.0 to +5.5
Max. Supply Current (µA) 300

The TC664 is a single PWM mode fan speed controller with FanSense TM technology for use with brush-less DC motors. The device allows temperature proportional speed control and therefore accomplishes lower acoustic fan noise and longer fan life. The TC664 reads the voltage provided by an external ther-mistor (or voltage output temperature sensor) and adjusts a 30% to 100% PWM duty cycle output to the fan with respect to the input temperature voltage. The PWM duty cycle can also be programmed via SMBus to allow fan speed control without the need of an external thermistor.In normal fan operation, pulse trains are present at the SENSE pin. These pulses are used to calculate the fan RPM. The fan RPM data is used to detect a worn out, stalled, open or unconnected fan. An RPM level below the user-programmable threshold causes the TC664 to assert a logic low alert signal (FAULT). Thedefault value is 500RPM. The TC664 consumes only 0.3mA during operation and can also enter a low-power shutdown mode by setting the appropriate bit in the configuration register.
TC664 Vendor
Microchip
TC664 Categories
Fan Controllers

Parameter Value
Typical Accuracy (°C) Depends on external thermistor
Maximum Accuracy @ 25°C Depends on external thermistor
Maximum Temperature Range (°C) -40 to +85
Vcc Range (V) +3.0 to +5.5
Max. Supply Current (µA) 300

The TC655 is a dual PWM mode fan speed controller with FanSense TM technology for use with brush-less DC motors. The device allows temperature proportional speed control and therefore accomplishes lower acoustic fan noise and longer fan life. The TC655 reads the voltage provided by an external ther-mistor (or voltage output temperature sensor) and adjusts a 30% to 100% PWM duty cycle output to the fan with respect to the input temperature voltage. The PWM duty cycle can also be programmed via SMBus to allow fan speed control without the need of an external thermistor.In normal fan operation, pulse trains are present at the SENSE pin. These pulses are used to calculate the fan RPM. The fan RPM data is used to detect a worn out, stalled, open or unconnected fan. An RPM level below the user-programmable threshold causes the TC655 to assert a logic low alert signal (FAULT). Thedefault value is 500RPM. The TC655 consumes only 0.3mA during operation and can also enter a low-power shutdown mode by setting the appropriate bit in the configuration register.
TC655 Vendor
Microchip
TC655 Categories
Fan Controllers

Parameter Value
Typical Accuracy (°C) Depends on external thermistor
Maximum Accuracy @ 25°C Depends on external thermistor
Maximum Temperature Range (°C) -40 to +85
Vcc Range (V) +3.0 to +5.5
Max. Supply Current (µA) 300

The TC654 is a dual PWM mode fan speed controller with FanSense TM technology for use with brush-less DC motors. The device allows temperature proportional speed control and therefore accomplishes lower acoustic fan noise and longer fan life. The TC654 reads the voltage provided by an external ther-mistor (or voltage output temperature sensor) and adjusts a 30% to 100% PWM duty cycle output to the fan with respect to the input temperature voltage. The PWM duty cycle can also be programmed via SMBus to allow fan speed control without the need of an external thermistor.In normal fan operation, pulse trains are present at the SENSE pin. These pulses are used to calculate the fan RPM. The fan RPM data is used to detect a worn out, stalled, open or unconnected fan. An RPM level below the user-programmable threshold causes the TC654 to assert a logic low alert signal (FAULT). Thedefault value is 500RPM. The TC654 consumes only 0.3mA during operation and can also enter a low-power shutdown mode by setting the appropriate bit in the configuration register.
TC654 Vendor
Microchip
TC654 Categories
Fan Controllers

Parameter Value
Typical Accuracy (°C) Depends on external thermistor
Maximum Accuracy @ 25°C Depends on external thermistor
Maximum Temperature Range (°C) -40 to +85
Vcc Range (V) +3.0 to +5.5
Max. Supply Current (µA) 300