ADM823:  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

ADM823:  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

    ADM823 Diagram
    Functional Block Diagram for ADM823

    Specifications

    Batt-Backup-Flg No
    Manual Reset Capability Yes
    Package SC70,SOT
    Power Fail Indicator No
    Reset Threshold Summary 7 Options--2.19 to 4.63V
    Reset Output-Stage Active-Low/Push-Pull
    Min Reset Timeout (ms) 140
    Typ Watchdog Timeout (ms) 1600
    Watchdog Timer Yes

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    Part# Reset Threshold Summary Min Reset Timeout (ms) Reset Output-Stage Manual Reset Capability Typ Watchdog Timeout (ms) Power Fail Indicator Package Product Description Price* (1000-4999)
    AD5100 Programmable Adj Active-Low/Push-Pull Yes adj. Yes SOP System-Mgmt IC with Programmable Quad Voltage Monitoring and Supervisory Functions $1.60
    ADM1232 4.37V & 4.62V 250 Active-High/Push-Pull, Active-Low/Open-Drain Yes 250, 500, 62.5 No DIP, SOIC, SOP Microprocessor Supervisory Circuit $0.95
    ADM13305 5 Options--0.6Adj to 4.55 140 Active-High/Push-Pull, Active-Low/Push-Pull Yes 1.6 - SOIC Dual Processor Supervisor with Watchdog $0.96
    ADM6316 26 Options--2.5 to 5V 1, 1,200, 140, 20 Active-Low/Push-Pull Yes 102, 1,600, 25,600, 6.3 No SOT Supervisory Ckt w/ Watchdog, Manual Reset & Active-Low, Push-Pull Reset Output in 5-Lead SOT-23 $0.51
    ADM6318 26 Options--2.5 to 5V 1, 1,200, 140, 20 Active-High/Push-Pull, Active-Low/Push-Pull No 102, 1,600, 25,600, 6.3 No SOT Supervisory Circuit with Watchdog and Dual Active-Low/Active-High Push-Pull Reset Outputs $0.50
    ADM6320 26 Options--2.5 to 5V 1, 1,200, 140, 20 Active-Low/Open-Drain Yes 102, 1,600, 25,600, 6.3 No SOT Supervisory Circuit with Watchdog, Manual Reset & Active-Low, Open-Drain Reset Output $0.51
    ADM6321 26 Options--2.5 to 5V 1, 1,200, 140, 20 Active-High/Push-Pull, Active-Low/Open-Drain No 102, 1,600, 25,600, 6.3 No SOT Supervisory Circuit with Watchdog and Dual Active-Low Open-Drain/Active-High Push-Pull Reset Outputs $0.51
    ADM6821 9 Options--1.58 to 4.63V 140 Active-High/Push-Pull Yes 1,600 No SOT Low Voltage Supervisory Circuit w/ Watchdog, Manual Reset and Active-High, Push-Pull Reset Output -
    ADM6822 9 Options--1.58 to 4.63V 140 Active-Low/Open-Drain Yes 1,600 No SOT Low Voltage Supervisory Circuit w/ Watchdog, Manual Reset and Open-Drain Reset Output -
    ADM6823 9 Options--1.58 to 4.63V 140 Active-Low/Push-Pull Yes 1,600 No SOT Low Voltage Supervisory Circuit w/ Watchdog, Manual Reset and Active-Low, Push-Pull Reset Output $0.76
    ADM6824 9 Options--1.58 to 4.63V 140 Active-High/Push-Pull, Active-Low/Push-Pull No 1,600 No SOT Low Voltage Supervisory Circuit w/ Watchdog, Manual Reset, Active-Hi & Low Push-Pull Reset Output -
    ADM699 4.65V 140 Active-High/Push-Pull, Active-Low/Push-Pull No 1,600 No DIP, SOIC µP Supv w/ Watchdog, 4.65V Trip Point, Low Supply Current and Active Low Reset Output $1.68
    ADM705 4.65V 160 Active-Low/Push-Pull Yes 1,600 Yes DIP, SOIC µP Supv w/ 4.65V Trip Voltage, Watchdog, Pwr Fail, Manual Reset & Active Low Reset Output $1.02
    ADM706 4.4V 160 Active-Low/Push-Pull Yes 1,600 Yes DIP, SOIC +3V, Voltage Monitoring µP Supervisory Circuit $1.70
    ADM823 7 Options--2.19 to 4.63V 140 Active-Low/Push-Pull Yes 1,600 No SC70, SOT