DS1231:Power Monitor

With precise, temperature-compensated comparators, the DS1231 Power Monitor Chip monitors input power and a 5V system power supply. If unsafe voltages are detected, a nonmaskable interrupt sends a warning signal to the processor in advance of power failure. Processing is unconditionally halted when power falls below a user-selectable 5% or 10% threshold level, with time to shutdown proportional to the available hold-up time of the power supply. Upon return of power, the DS1231 maintains reset until power conditions stabilize. The DS1231 enhances system reliability by closely monitoring both processor and upstream power levels, warning of impending failure, and automatically suspending and restarting processor operation. An input sense also supports a connection to switched inputs such as an opto-isolator for LED function. All external reset components (i.e., pull-up resistor and delay timing capacitor) are contained in one package, saving space and cost.

Key Features
  • Monitors input and power supply and warns of impending failure
  • Provides orderly shutdown
  • Initiates and holds processor reset until levels are unsafe
  • Tolerance threshold levels can be set for 5% or 10%
  • Automatically restarts processor on power-up
  • Pauses restart until system stabilizes
  • Operating range: 0°C to +70°C (DS1231 and DS1231S) -40°C to +85°C (DS1231-N and DS1231S-N)
  • Optional active-low NMI Hysteresis (200mV = "-20", 350mV = "-35", 500mV = "-50")
DS1231: Block Diagram
DS1231: Block Diagram
DataSheet
titleDownload file
DS1231 Data SheetDS1231.pdf
Parametrics
Part NumberReset Thresh.
(V)
Reset OuttRESETWatchdog FeatureSupervisor FeaturesReset Thresh. Accur.
(%)
ICC
(µA)
Package/PinsBudgetary
Price
min@ +25°CmaxSee Notes
DS12313.3 to 5.5Active Low
Open Drain
85ms to 300msNo WatchdogPower Fail Comparator/Low Battery Detect2.52000PDIP(N)/8
SOIC(W)/16
$3.65 @1k
Quality and Environmental Data
Ordering Information
Part NumberNotesStatusRecommended ReplacementPackageTempRoHS
DS1231-20200mV HysteresisNo Longer AvailableDS1231-20+PDIP(N),;8 pin;79.7 mm²0°C to +70°CNo
DS1231-20+200mV HysteresisActivePDIP(N),;8 pin;79.7 mm²0°C to +70°CLead Free
DS1231-20N200mV HysteresisNo Longer AvailableDS1231-20N+PDIP(N),;8 pin;79.7 mm²-40°C to +85°CNo
DS1231-20N+ActivePDIP(N),;8 pin;79.7 mm²-40°C to +85°CLead Free
DS1231-35350mV HysteresisNo Longer AvailableDS1231-35+PDIP(N),;8 pin;79.7 mm²0°C to +70°CNo
DS1231-35+ActivePDIP(N),;8 pin;79.7 mm²0°C to +70°CLead Free
DS1231-35N350mV HysteresisNo Longer AvailableDS1231-35N+PDIP(N),;8 pin;79.7 mm²-40°C to +85°CNo
DS1231-35N+ActivePDIP(N),;8 pin;79.7 mm²-40°C to +85°CLead Free
DS1231-50500mV HysteresisNo Longer AvailableDS1231-50+PDIP(N),;8 pin;79.7 mm²0°C to +70°CNo
DS1231-50+ActivePDIP(N),;8 pin;79.7 mm²0°C to +70°CLead Free
Part NumberNotesStatusRecommended ReplacementPackageTempRoHS
DS1231-50/GNo Longer AvailablePDIP(N),;8 pin;79.7 mm²0°C to +70°CNo
DS1231-50N500mV HysteresisNo Longer AvailableDS1231-50N+PDIP(N),;8 pin;79.7 mm²-40°C to +85°CNo
DS1231-50N+ActivePDIP(N),;8 pin;79.7 mm²-40°C to +85°CLead Free
DS1231S-20200mV HysteresisNo Longer AvailableDS1231S-20+SOIC(W),;16 pin;111.8 mm²0°C to +70°CNo
DS1231S-20+ActiveSOIC(W),;16 pin;111.8 mm²0°C to +70°CLead Free
DS1231S-20+T&RActiveSOIC(W),;16 pin;111.8 mm²0°C to +70°CLead Free
DS1231S-20/T&R200mV HysteresisNo Longer AvailableDS1231S-20+T&RSOIC(W),;16 pin;111.8 mm²0°C to +70°CNo
DS1231S-20N200mV HysteresisNo Longer AvailableDS1231S-20N+SOIC(W),;16 pin;111.8 mm²-40°C to +85°CNo
DS1231S-20N+ActiveSOIC(W),;16 pin;111.8 mm²-40°C to +85°CLead Free
DS1231S-35350mV HysteresisNo Longer AvailableDS1231S-35+SOIC(W),;16 pin;111.8 mm²0°C to +70°CNo
Part NumberNotesStatusRecommended ReplacementPackageTempRoHS
DS1231S-35+ActiveSOIC(W),;16 pin;111.8 mm²0°C to +70°CLead Free
DS1231S-35/T&R350mV HysteresisNo Longer AvailableDS1231S-35+T&RSOIC(W),;16 pin;111.8 mm²0°C to +70°CNo
DS1231S-35N/T&RActiveSOIC(W),;16 pin;111.8 mm²-40°C to +85°CNo
DS1231S-50500mV HysteresisNo Longer AvailableDS1231S-50+SOIC(W),;16 pin;111.8 mm²0°C to +70°CNo
DS1231S-50+ActiveSOIC(W),;16 pin;111.8 mm²0°C to +70°CLead Free
DS1231S-500+T&RActiveSOIC(W),;16 pin;111.8 mm²0°C to +70°CLead Free
DS1231S-500/T&RActiveDS1231S-20+T&RSOIC(W),;16 pin;111.8 mm²0°C to +70°CNo
DS1231S-50N500mV HysteresisNo Longer AvailableDS1231S-50+SOIC(W),;16 pin;111.8 mm²-40°C to +85°CNo
DS1231S-50N+No Longer AvailableSOIC(W),;16 pin;111.8 mm²-40°C to +85°CLead Free
DS1231S-50N/T&RActiveSOIC(W),;16 pin;111.8 mm²-40°C to +85°CNo
DS1231.pdf DS1231
DS1231.pdf DS1231
DS1231.pdf DS1231
Adding Hysteresis to CPU Supervisor Voltage Sense Inputs Monitoring Upstream Voltage Supplies for Power-Fail Warnings DS1831E
DS1231.pdf DS1231
原理框图 DS1231