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The X40430, X40431, X40434, X40435 combines power-on reset control, watchdog timer, supply voltage supervision, second and third voltage supervision, manual reset, and Block Lock™ protect serial EEPROM in one package. This combination lowers system cost, reduces board space requirements, and increases reliability.

Applying voltage to V_CC activates the power-on reset circuit which holds RESET/RESET active for a period of time. This allows the power supply and system oscillator to stabilize before the processor can execute code.

Low V_CC detection circuitry protects the user's system from low voltage conditions, resetting the system when V_CC falls below the minimum VTRIP1 point. RESET/RESET is active until V_CC returns to proper operating level and stabilizes. A second and third voltage monitor circuit tracks the unregulated supply to provide a power fail warning or monitors different power supply voltage. Three common low voltage combinations are available. However, Intersil's unique circuits allows the threshold for either voltage monitor to be reprogrammed to meet specific system level requirements or to fine-tune the threshold for applications requiring higher precision.

A manual reset input provides debounce circuitry for minimum reset component count.

The Watchdog Timer provides an independent protection mechanism for microcontrollers. When the microcontroller fails to restart a timer within a selectable time out interval, the device activates the WDO signal. The user selects the interval from three preset values. Once selected, the interval does not change, even after cycling the power.

The memory portion of the device is a CMOS Serial EEPROM array with Intersil's Block Lock protection. The array is internally organized as x 8. The device features a 2-wire interface and software protocol allowing operation on an I²C bus.

The device utilizes Intersil's proprietary Direct Write™ cell, providing a minimum endurance of 100,000 cycles and a minimum data retention of 100 years.

Key Features

• Monitoring voltages: 5V to 9V
• Independent core voltage monitor
• Triple voltage detection and reset assertion
  • Standard reset threshold settings. See selection table on page 2.
  • Adjust low voltage reset threshold voltages using special programming sequence
  • Reset signal valid to VCC = 1V
  • Monitor three separate voltages
• Fault detection register
• Selectable power-on reset timeout (0.05s, 0.2s, 0.4s, 0.8s)
• Selectable watchdog timer interval (25ms, 200ms, 1.4s or off)
• Debounced manual reset input
• Low power CMOS
  • 25µA typical standby current, watchdog on
  • 6µA typical standby current, watchdog off
• Memory security
• 4Kbits of EEPROM
  • 16 byte page write mode
  • 5ms write cycle time (typical)
• Built-in inadvertent write protection
  • Power-up/power-down protection circuitry
  • Block lock protect 0, or 1/2, of EEPROM
• 400kHz 2-wire interface
• 2.7V to 5.5V power supply operation
• Available packages
  • 14-lead SOIC, TSSOP

Applications

• Communication Equipment
  • Routers, Hubs, Switches
  • Disk Arrays, Network Storage
• Industrial Systems
  • Process Control
  • Intelligent Instrumentation
• Computer Systems
  • Computers
  • Network Servers