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 VIT ≤ 3.3V. The reset delay time can be set to 20ms by disconnecting the CT pin, 300ms by connecting the CT pin to VDD using a resistor, or can be user-adjusted between 1.25ms and 10s by connecting the CT 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 (TJ).

• Power-On Reset Generator withAdjustable Delay Time: 1.25ms to 10s
• Very Low Quiescent Current: 2.4µA typ
• High Threshold Accuracy: 0.5% typ
• Fixed Threshold Voltages for Standard Voltage Rails from 0.9V to 5V and Adjustable Voltage Down to 0.4V Are Available
• Manual Reset (MR) Input
• Open-Drain RESET Output
• Temperature Range: -40°C to +125°C
• Small SOT23 and 2mm × 2mm QFN Packages
• APPLICATIONS
  • DSP or Microcontroller Applications
  • Notebook/Desktop Computers
  • PDAs/Hand-Held Products
  • Portable/Battery-Powered Products
  • FPGA/ASIC Applications

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