The X4043/45 combines four popular functions, Power-on Reset Control, Watchdog Timer, Supply Voltage Supervision, and Block Lock Protect Serial EEPROM Memory in one package. This combination lowers system cost, reduces board space requirements, and increases reliability.

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

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 RESET/RESET signal. The user selects the interval from three preset values. Once selected, the interval does not change, even after cycling the power.

The device's low V_CC detection circuitry protects the user's system from low voltage conditions, resetting the system when V_CC falls below the minimum V_CC trip point. RESET/RESET is asserted until V_CC returns to proper operating level and stabilizes. Five industry standard VTRIP thresholds are available, however, Intersil's unique circuits allow the threshold to be reprogrammed to meet custom requirements or to fine-tune the threshold for applications requiring higher precision.

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 an 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 1,000,000 cycles and a minimum data retention of 100 years.

• Selectable watchdog timer
• Low V_CC detection and reset assertion
  • Five standard reset threshold voltages
  • Adjust low V_CC reset threshold voltage using special programming sequence
  • Reset signal valid to V_CC = 1V
• Low power CMOS
  • <20ìA max standby current, watchdog on
  • <1ìA standby current, watchdog OFF
  • 3mA active current
• 4kbits of EEPROM
  • 16-byte page write mode
  • Self-timed write cycle
  • 5ms write cycle time (typical)
• Built-in inadvertent write protection
  • Power-up/power-down protection circuitry
  • Protect 0, 1/4, 1/2, all or 16, 32, 64 or 128 bytes of EEPROM array with Block Lock™ protection
• 400kHz 2-wire interface
• 2.7V to 5.5V power supply operation
• Available packages
  • 8 Ld SOIC
  • 8 Ld MSOP
  • 8 Ld PDIP
• Pb-free plus anneal available (RoHS compliant)