ADM825:  Supervisory Circuit with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23

The ADM823/ADM824/ADM825 are supervisory circuits that monitor power supply voltage levels and code execution integrity in microprocessor-based systems. In addition to providing power-on reset ...More

ADM825:  Supervisory Circuit with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23

Product Description

The ADM823/ADM824/ADM825 are supervisory circuits that monitor power supply voltage levels and code execution integrity in microprocessor-based systems. In addition to providing power-on reset signals, an on-chip watchdog timer can reset the microprocessor if it fails to strobe within a preset timeout period. A reset signal can also be asserted by an external push-button, through a manual reset input. The three parts feature different combinations of watchdog input, manual reset input, and output stage configuration, as shown in Table 1.

These parts are available in a choice of seven reset threshold options ranging from 2.19 V to 4.63 V. The reset and watchdog timeout periods are fixed at 140 ms (minimum) and 1.6 sec (typical), respectively.

The ADM823/ADM824/ADM825 are available in 5-lead SC70 and SOT-23 packages and typically consume only 5 μA, making them suitable for use in low power, portable applications.

Applications

  • Microprocessor systems
  • Computers
  • Controllers
  • Intelligent instruments
  • Portable equipment

    • Data Sheet, Rev. B, 5/08

    Features

    • Precision 2.5 V to 5 V power supply monitor
    • 7 reset threshold options: 2.19 V to 4.63 V
    • 140 ms (minimum) reset timeout
    • Manual reset input (ADM823, ADM825)
    • Push-pull output stages
      RESET (ADM823)
      RESET, RESET (ADM824/ADM825)
    • Watchdog timer with 1.6 sec timeout (ADM823, ADM824)
    • Low power consumption (5 μA)
    • See Data Sheet for Additional Information

    Diagrams

    • Enlarge
    • Symbols and Footprints
    ADM825 Diagram
    Pin Configuration Diagram for ADM825

    Specifications

    # of Monitored Voltages 1
    Backup-Battery Switch No
    Manual Reset Capability Yes
    Package SC70,SOT
    Reset Threshold Summary 7 Options--2.19 to 4.63V
    Reset Output-Stage Active-High/Push-Pull,Active-Low/Push-Pull
    Min Reset Timeout (ms) 140
    Watchdog Timer No

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    Part# Reset Threshold Summary Min Reset Timeout (ms) Reset Output-Stage Manual Reset Capability Package Price* (1000-4999)
    ADM1810 4.35V & 4.62V 100 Active-Low/Push-Pull No SC70, SOT $0.46
    ADM1811 4.35V & 4.62V 100 Active-Low/Int-Pullup No SC70, SOT $0.46
    ADM1812 4.35V & 4.62V 100 Active-High/Push-Pull No SC70, SOT $0.46
    ADM1813 4.35V & 4.62V 100 Active-Low/Int-Pullup Yes SC70, SOT $0.39
    ADM1815 5 Options--2.18 to 3.06V 100 Active-High/Push-Pull No SC70, SOT $0.39
    ADM1816 5 Options--2.18 to 3.06V 100 Active-Low/Int-Pullup No SC70, SOT $0.46
    ADM1817 5 Options--2.18 to 3.06V 100 Active-High/Push-Pull No SC70, SOT $0.46
    ADM1818 5 Options--2.18 to 3.06V 100 Active-Low/Int-Pullup Yes SC70, SOT $0.45
    ADM6315 6 Options--2.63 to 4.63V 1, 1,120, 140, 20 Active-Low/Open-Drain Yes SOT $0.81
    ADM6319 26 Options--2.5 to 5V 1, 1,120, 140, 20 Active-High/Push-Pull, Active-Low/Push-Pull Yes SOT $0.50
    ADM6322 26 Options--2.5 to 5V 1, 1,200, 140, 20 Active-High/Push-Pull, Active-Low/Open-Drain Yes SOT $0.51
    ADM6384 31 Options--1.58 to 5.0V 1, 1,120, 140, 20 Active-Low/Push-Pull Yes SC70 $0.95
    ADM6711 6 Options--2.32 to 4.63V 140 Active-Low/Push-Pull Yes SC70 $0.26
    ADM6713 6 Options--2.32 to 4.63V 140 Active-Low/Open-Drain Yes SC70 $0.28
    ADM6825 9 Options--1.58 to 4.63V 140 Active-High/Push-Pull, Active-Low/Push-Pull Yes SOT -
    ADM698 4.65V 140 Active-High/Push-Pull, Active-Low/Push-Pull No DIP, SOIC $1.37
    ADM707 4.65V 160 Active-High/Push-Pull, Active-Low/Push-Pull Yes DIP, SOIC $0.97
    ADM708 4 Options--2.63 to 4.4V 160 Active-High/Push-Pull, Active-Low/Push-Pull Yes DIP, SOIC, SOP $0.85
    ADM709 5 Options--2.63 to 4.65V 140 Active-Low/Push-Pull No DIP, SOIC $0.71