OVERVIEW
The S42xxx are a precision power supervisory circuit. It automatically monitors the device’s VCC level and will generate a reset output on two complementary open drain outputs. In addition to the VCC monitoring, the S42xxx also provides a second voltage comparator input. This input has an independent open drain output that can be wire-OR’ed with the RESET I/O or it can be used as a system interrupt.
The S42xxx also has an integrated 4k/16k-bit nonvolatile memory. The memory conforms to the industry standard two-wire serial interface. In addition to the reset circuitry, the S42WD42/S42WD61 also has a watchdog timer.

FEATURES
• Precision Dual Voltage Monitor
   – VCC Supply Monitor
   - Dual reset outputs for complex
      microcontroller systems
   - Integrated memory write lockout function
   - No external components required
• Second Voltage Monitor Output
   – Separate VLOW output
   – Generates interrupt to MCU
   – Generates RESET for dual supply systems
   - Guaranteed output assertion to VCC - 1V
• Watchdog Timer (S42WD42, S42WD61)
   – 1.6s
• Memory Internally Organized 2 x8
• Extended Programmable Functions
   Available on SMS24
• High Reliability
   – Endurance: 100,000 erase/write cycles
   – Data retention: 100 years