These devices can be used in conjunction with positive temperature coefficient (PTC) thermistors to detect overheating conditions within electronic systems so that countermeasures can be taken if necessary. They apply to a wide range of applications , including household appliances, mobile equipment, industrial equipment.
Thermoflagger devices provide an inexpensive, simple, low current consumption solution to interface to multiple PTC thermistors. By combining them with a general-purpose temperature sensor IC, an additional over-temperature protection solution can be implemented. They are TCTH021BE which has a non-latch function for the FLAG signal when an abnormal state is detected, and TCTH022BE which has a latch function for this signal.
The new TCTH021BE and TCTH022BE Thermoflagger products, both used in conjunction with PTC thermistors, have a built-in current source that increases its ohmic resistance value if a certain temperature level is exceeded. An increase in temperature close to any PTC will cause the voltage on the PTCO pin to increase, causing the FLAG signal to be asserted, thereby detecting an overheating condition. Overtemperature detection at multiple locations can be easily achieved by connecting multiple thermistors in series.
These products are housed in a small standard SOT-553 package measuring only 1.6x1.6x0.55mm. They have a low current consumption (IDD10U) of 11.3 μA (typ) and selectable PTCO output current. Typically, IPTCO is 10 μA with an accuracy of up to ±8%.
The operating supply voltage (VDD) can be in the range of 1.7-5.5V and the device can be operated from -40ºC to +125ºC.
Both products allow users to easily configure overheating detection for the entire electronic device without significantly impacting the size and power consumption of the device.
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