MAX6821:Low-Voltage SOT23 µP Supervisors with Manual Reset and Watchdog Timer

The MAX6821—MAX6825 are low-voltage microprocessor (µP) supervisory circuits that combine voltage monitoring, watchdog timer, and manual reset input functions in a 5-pin SOT23 package. Microprocessor supervisory circuits significantly improve system reliability and accuracy compared to separate ICs or discrete components. These devices assert a reset signal whenever the monitored voltage drops below its preset threshold, keeping it asserted for a minimum timeout period after VCC rises above the threshold. In addition, a watchdog timer monitors against code execution errors. A debounced manual reset is also available. The MAX6821—MAX6825 monitor voltages from +1.8V to +5.0V. These outputs are guaranteed to be in the correct state for VCC down to +1.0V. Nine preprogrammed reset threshold voltages are available (see the Threshold Suffix Guide). The MAX6821, MAX6822, and MAX6823 all have a manual reset input and a watchdog timer. The MAX6821 has push-pull RESET, the MAX6822 has open-drain active-low RESET, and the MAX6823 has push-pull active-low RESET. The MAX6824 has a watchdog timer and both push-pull active-low RESET and push-pull RESET. The MAX6825 has a manual reset input and both push-pull active-low RESET and push-pull RESET. The Selector Guide explains the functions offered in this series of parts.

Key Features
  • Monitors +1.8V, +2.5V, +3.0V, +3.3V, +5.0V Supplies
  • 140ms (min) Reset Timeout Delay
  • 1.6s Watchdog Timeout Period (MAX6821/MAX6822/MAX6823/MAX6824)
  • Manual Reset Input (MAX6821/MAX6822/MAX6823/MAX6825)
  • Three Reset Output Options
    • Push-Pull Active-Low RESET
    • Push-Pull RESET
    • Open-Drain Active-Low RESET
  • Guaranteed Reset Valid to VCC = +1.0V
  • Immune to Short Negative VCC Transients
  • No External Components
  • Small 5-Pin SOT23 Packages
MAX6821, MAX6822, MAX6823, MAX6824, MAX6825: Typical Operating Circuit
MAX6821, MAX6822, MAX6823, MAX6824, MAX6825: Typical Operating Circuit
Applications/Uses
  • Computers and Controllers
  • Critical µP Monitoring
  • Embedded Controllers
  • Intelligent Instruments
  • Portable Battery-Powered Equipment
  • Set-Top Boxes
DataSheet
titleDownload file
MAX6821-MAX6825 Data SheetMAX6821-MAX6825.pdf
Parametrics
Part NumberReset Thresh.
(V)
Reset OuttRESETWatchdog FeatureWatchdog TimeoutSupervisor FeaturesReset Thresh. Accur.
(%)
ICC
(µA)
Package/PinsBudgetary
Price
min@ +25°CmaxSee Notes
MAX68211.2 to 1.8
1.8 to 2.5
2.5 to 3.3
3.3 to 5.5
Active High
Push-Pull
85ms to 300msInput (WDI)1s to 2sManual Reset2.516SOT/5$1.55 @1k
MAX6822Active Low
Open Drain
Input (WDI)1s to 2sManual Reset16SOT/5$1.55 @1k
MAX6823Active Low
Push-Pull
Input (WDI)1s to 2sManual Reset16SOT/5$1.77 @1k
MAX6824Active High
Active Low
Push-Pull
Input (WDI)1s to 2s-16SOT/5$1.77 @1k
MAX6825Active High
Active Low
Push-Pull
No Watchdog-Manual Reset12SOT/5$1.55 @1k
Quality and Environmental Data
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX6821LUK-TNo Longer AvailableSOT,;5 pin;9 mm²-40°C to +125°CNo
MAX6821MUK-TNo Longer AvailableSOT,;5 pin;9 mm²-40°C to +125°CNo
MAX6821RUK+ActiveSOT,;5 pin;9 mm²-40°C to +125°CLead Free
MAX6821RUK+TActiveSOT,;5 pin;9 mm²-40°C to +125°CLead Free
MAX6821RUK-TNo Longer AvailableMAX6821RUK+TSOT,;5 pin;9 mm²-40°C to +125°CNo
MAX6821SUK+ActiveSOT,;5 pin;9 mm²-40°C to +125°CLead Free
MAX6821SUK+TActiveSOT,;5 pin;9 mm²-40°C to +125°CLead Free
MAX6821SUK-TNo Longer AvailableMAX6821SUK+TSOT,;5 pin;9 mm²-40°C to +125°CNo
MAX6821TUK-TNo Longer AvailableSOT,;5 pin;9 mm²-40°C to +125°CNo
MAX6821VUK-TNo Longer AvailableSOT,;5 pin;9 mm²-40°C to +125°CNo
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX6821WUK-TNo Longer AvailableSOT,;5 pin;9 mm²-40°C to +125°CNo
MAX6821YUK-TNo Longer AvailableSOT,;5 pin;9 mm²-40°C to +125°CNo
MAX6821ZUK-TNo Longer AvailableSOT,;5 pin;9 mm²-40°C to +125°CNo
MAX6821-MAX6825.pdf MAX6825
MAX6821.pdf MAX6821
典型工作电路 MAX6825