The RT9818 is a micro-power voltage detector supervising the power supply voltage level for microprocessors (μP) or digital systems. It provides internally fixed threshold levels with 0.1V per step ranging from 1.2V to 5V, which covers most digital applications. It features low supply current of 3μA. The RT9818 performs supervisory function by sending out a reset signal whenever the VDD voltage falls below a preset threshold level. This reset signal will last the whole period before VDD recovering. Once VDD recovered upcrossing the threshold level, the reset signal will be released after a certain delay time. RT9818 is provided in SC-82, SC-70-3, SOT-23-3, SOT-23-5 and SOT-89 packages.


  • Computers
  • Controllers
  • Intelligent Instruments
  • Critical μP and μC Power Monitoring
  • Portable/Battery-Powered Equipment
Key Spec.
RT9818A RT9818B RT9818C RT9818D RT9818E RT9818F RT9818G
Status Active Active Active Active Active Active Active
Vin (min) (V) 0.9 0.9 0.9 0.9 0.9 0.9 0.9
Vin (max) (V) 6 6 6 6 6 6 6
VTH (min) (V) 1.2 1.2 1.2 1.2 1.2 1.2 1.2
VTH (max) (V) 5 5 5 5 5 5 5
Accuracy (±%) 1.5 1.5 1.5 1.5 1.5 1.5 1.5
Reset Active Type Low(Open Drain) Low Low Low High High High
Reset Time-out Period (typ) (ms) 0 55 220 450 0 55 220
Reset Delay Time (typ) (ms) 0.02 0.02 0.02 0.02 0.02 0.02 0.02
Package Type SOT-23;SOT-25;SC-70-3;SC-82;SOT-89 SOT-23;SOT-25;SC-70-3;SC-82;SOT-89 SOT-23;SOT-25;SC-70-3;SC-82;SOT-89 SOT-23;SOT-25;SC-70-3;SC-82;SOT-89 SOT-23;SOT-25;SC-70-3;SC-82;SOT-89 SOT-23;SOT-25;SC-70-3;SC-82;SOT-89 SOT-23;SOT-25;SC-70-3;SC-82;SOT-89
  • Internally Fixed Threshold 1.2V to 5V in 0.1V Step
  • High Accuracy ±1.5%
  • Low Supply Current 3μA
  • No External Components Required
  • Quick Reset within 20μs
  • Built-in Recovery Delay Include 0ms, 55ms, 220ms, 450ms Options
  • Low Functional Supply Voltage 0.9V
  • N-Channel Open-Drain Output
  • Small SC-82, SC-70-3, SOT-23-3, SOT-23-5, SOT-89 Packages
  • RoHS Compliant and 100% Lead (Pb)-Free
TitleLast UpdateShareDownload
Micro-Power Voltage Detectors2005/04/13
Title Last Update ShareDownload
Micro-Power Voltage Detectors 2015/05/19
Technical Documents
TitleLast UpdateShareDownload
Richtek Selection Guide [Oct., 2022]2022/10/01
Power Management for Video Doorbell2021/10/08
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT9818A-27GVSOT-233000 Request Not available
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RT9818D-27GVSOT-233000 Request Buy from Distributor
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