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The TPS3818xxx family of microprocessor supervisory circuitsmonitor system voltages from 0.4V to 5.0V, asserting an open-drain RESET signal when the SENSE voltage drops below a preset threshold or when the manual reset (MR) pin drops to a logic low. The RESET output remains low for the user-adjustable delay time after the SENSE voltage and manual reset (MR) return above the respective thresholds.

The TPS3818 uses a precision reference to achieve 0.5% threshold accuracy for V_IT ≤ 3.3V. The reset delay time can be set to 20ms by disconnecting the C_T pin, 300ms by connecting the C_T pin to V_DD using a resistor, or can be user-adjusted between 1.25ms and 10s by connecting the C_T pin to an external capacitor. When used with an external capacitor, the TPS3818xxx gives a more accurate delay time than the similar TPS3808xxx device. The TPS3818 has a very low typical quiescent current of 2.4µA so it is well-suited to battery-powered applications. It is available in either a small SOT23 and an ultra-small 2mm × 2mm QFN PowerPAD package, and is fully specified over a temperature range of -40°C to +125°C (T_J).