Diodes Incorporated

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The APX803S is 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 5.0V, 3.3V, 3.0V and 2.5V powered circuits.

These circuits perform a single function: they assert a reset signal on power up and whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for a fixed period of time after VCC has risen above the reset threshold. For the APX803S this period is a minimum of 1ms while for other APX803S variants it is at least 140ms. 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.

The APX803S is available with different reset thresholds suitable for operation with a variety of supply voltages. The APX803S has an open drain active low output and compliment Diodes APX809S/810S which have push-pull output stages. Low supply current makes the APX803S ideal for use in portable equipment. The APX803S is available in two pin out variants of the 3-pin SOT23 package.


  • Open-drain, Active Low
  • Power-On/Power Supply Glitch Reset Pulse
  • 10µA Supply Current (Typ.)
  • Guaranteed Reset Valid to VCC = 1V


  • 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 Open-Drain
Ambient Temperature Range  (°C) -40 to 85 °C

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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


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