CPU Supervisor with 4kbit EEPROM

Product Status: Mass Production


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 VCC detection circuitry protects the user's system from low voltage conditions, resetting the system when VCC falls below the minimum VCC trip point. RESET /RESET is asserted until VCC 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 I2 C 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 VCC detection and reset assertion
  • Five standard reset threshold voltages
  • Adjust low VCC reset threshold voltage using special programming sequence
  • Reset signal valid to VCC = 1V
  • Low power CMOS
  • <20µA max standby current, watchdog on
  • <1µA 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)


 Block Diagram


Basic Information
Production Status
Mass Production
Supply Voltage Vs Range (V)
4.5 to 5.5, 4.5 to 5.5, 2.7 to 5.5, 2.7 to 5.5
Voltage Threshold 1 (V)
4.62 (2.6%), 4.38 (3%), 2.92 (2.4%), 2.62 (2.7%)
Reset Output Type
Active Low
Watchdog Timer
OFF, 0.6, 0.2, 1.4
Manual Reset
Bus/Output Interface
4 KBits
Battery Monitor and Switchover
Fault Detection Register
-4.5A, Blank, -2.7A, -2.7
POR (ms)
RTC Function
Qualification Level
Temperature Range
-40 to +85

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