Diodes Incorporated

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3-Pin Micro Power Voltage Detector

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The APX809S/810S are used for microprocessor (µP) supervisory circuits to monitor the power supplies in µP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V, +3.3V, +3.0V and +2.5V powered circuits.

These circuits perform a single function: they assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 240ms after VCC has risen above the reset threshold. Reset thresholds suitable for operation with a variety of supply voltages are available. The APX809S/810S have push pull outputs. The APX809S have an active low output, while the APX810S has an active high RESET output. The reset comparator is designed to ignore fast transients on VCC, and the outputs are guaranteed to be in the correct logic state for VCC down to 1V. Low supply current makes the APX809S/810S ideal for use in portable equipment.

The APX809S/810S is available in a 3-pin SOT23 packages.


  • Precision Monitoring of +2.5V, +3V, +3.3V, and +5V Power-Supply Voltages
  • Fully Specified Over-temperature
  • Available in three Output Configurations
  • Push-Pull Active Low (APX809S)
  • Push-Pull RESET Active High (APX810S)
  • 200ms Typ Power-On Reset Pulse Width
  • 10µA Supply Current (Typ.)
  • Guaranteed Reset Valid to VCC = +1V
  • No External Components


  • Computers
  • Controllers
  • Intelligent Instruments
  • Critical µP and µC Power Monitoring
  • Portable/Battery Powered Equipment

Product Specifications

Product Parameters

Fixed Detect Voltages (V) 2.25, 2.63, 2.93, 3.08, 4, 4.38, 4.63 V
Adjustable Detect Voltage Reference Voltage (V) N/A V
Number of Channels N/A
Minimum Operating Voltage (V) 1 V
Maximum Input Voltage (V) 5.5 V
Quiescent Current (µA) 10 µA
Typical Time Delay (µs) 50, 1.7, 240 µs
Reset Period (ms) N/A ms
RESET Output (Active High) No (Active High)
RESET Output (Active Low) Yes (Active Low)
Manual RESET No
Watchdog No
Watchdog Time (s) None s
Power Fail Comparator Threshold (V) None V
Reset Output Topology Push-Pull
Ambient Temperature Range  (°C) -40 to 125 °C

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Technical Documents

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Additional Technical Documents are available upon request:
Application information, Evaluation board, and Other technical documents

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Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN # Issue Date Implementation Date Subject
PCN-2348 2018-07-19 2018-10-19 Additional Qualified Assembly/Test (A/T) Site for Select Devices