DS1814A, DS1814B, DS1814C:5 Volt and 3.3 Volt MicroMonitor

The DS1814 5-Volt MicroMonitor and the DS1819 3.3V MicroMonitor monitor three vital conditions for a microprocessor: power supply, software execution, and external override. First, a precision temperature-compensated reference and comparator circuit monitor the status of VCC. When an out-of-tolerance condition occurs, an internal power-fail signal is generated which forces the reset(s) to an active state. When VCC returns to an in-tolerance condition, the reset signal is kept in the active state for a minimum of 140ms to allow the power supply and processor to stabilize. The DS1814/DS1819 ‘A' and ‘C' perform pushbutton reset control. They debounce the pushbutton input and generate an active reset pulse width of 140ms minimum. The DS1814/9 'A' and 'B' versions perform a watchdog function. The watchdog is an internal timer that forces the reset signals to the active state if the strobe input does not change state every 1.12 seconds. The watchdog timer function can be disabled by leaving the watchdog strobe input disconnected.

Key Features
  • Halts and restarts an out-of-control microprocessor
  • Holds microprocessor in check during power transients
  • Automatically restarts microprocessor after power failure
  • Monitors pushbutton for external override
  • Accurate 5%, 10%, or 20% (3V only) microprocessor power monitoring
  • Eliminates the need for discrete components
  • 20% tolerance for use with 3.0V systems
  • Pin- and function-compatible with the MAX823/24/25 products
  • Low cost SOT-23-5 package
  • Industrial temperature range: -40°C to +85°C
DS1814, DS1819: Block Diagram
DS1814, DS1819: Block Diagram
DataSheet
titleDownload file
DS1814-DS1819C Data SheetDS1814-DS1819C.pdf
Parametrics
Part NumberReset Thresh.
(V)
Reset OuttRESETWatchdog FeatureWatchdog TimeoutSupervisor FeaturesReset Thresh. Accur.
(%)
ICC
(µA)
Package/PinsBudgetary
Price
min@ +25°CmaxSee Notes
DS1814A3.3 to 5.5Active Low
Push-Pull
85ms to 300msInput (WDI)1s to 2sManual Reset2.515SOT/5$0.72 @1k
DS1814B3.3 to 5.5Active High
Active Low
Push-Pull
Input (WDI)1s to 2s-15SOT/5$0.72 @1k
DS1814C3.3 to 5.5Active High
Active Low
Push-Pull
No Watchdog-Manual Reset15SOT/5$0.72 @1k
DS1819A2.5 to 3.3Active Low
Push-Pull
Input (WDI)1s to 2sManual Reset12SOT/5$2.17 @1k
DS1819B2.5 to 3.3Active High
Active Low
Push-Pull
Input (WDI)1s to 2s-12SOT/5$2.17 @1k
DS1819C2.5 to 3.3Active High
Active Low
Push-Pull
No Watchdog-Manual Reset12SOT/5$2.17 @1k
Ordering Information
Part NumberNotesStatusRecommended ReplacementPackageTempRoHS
DS1814AR-10-UNo Longer AvailableDS1814AR-10-U+SOT,;5 pin;9 mm²-40°C to +85°CNo
DS1814AR-10-U+ActiveSOT,;5 pin;9 mm²-40°C to +85°CLead Free
DS1814AR-10/T&R5V-10%No Longer AvailableDS1814AR-10+T&RSOT,;5 pin;9 mm²-40°C to +85°CNo
DS1814AR-5+T&R5V-5%ActiveSOT,;5 pin;9 mm²-40°C to +85°CLead Free
DS1814AR-5-UNo Longer AvailableDS1814AR-5-U+SOT,;5 pin;9 mm²-40°C to +85°CNo
DS1814AR-5-U+ActiveSOT,;5 pin;9 mm²-40°C to +85°CLead Free
DS1814AR-5/T&R5V-5%No Longer AvailableDS1814AR-5+T&RSOT,;5 pin;9 mm²-40°C to +85°CNo
DS1814-DS1819C.pdf DS1819C
Using the DS1814 MicroMonitor to Control Microprocessor Resets DS1814C
原理框图 DS1819