CAT1021, CAT1022 and CAT1023 are complete memory and supervisory solutions microcontrollerbased systems. A 2K-bit serial EEPROM memory and system power monitoring with brownout protection are integrated in low-power CMOS technology. via a 400kHz I2C bus memory interface. The CAT1021 and CAT1023 provide an accurate VCC detection circuit and two open-drain outputs: (reset) drive high, and the other (reset) drive low when VCC falls below the reset threshold voltage. The CAT1022 is only a reset output and has no write-protected inputs. The CAT1021 also has a write protect input (WP). Connected to a logic high if WP is disabled for write operations. All supervisors have a 1.6 second watchdog timer circuit that resets the system to a known state and halts or "hangs" the system if a software or hardware failure occurs. For CAT1021 and CAT1022, the watchdog timer monitors the SDA signal. The CAT1023 has a separate watchdog timer interrupt input pin, "WDI". Power supply monitoring and reset circuits protect memory against power-up/power-down conditions and system controller power-down conditions. Five reset threshold voltages support 5V, 3.3V and 3V systems. If the supply voltage tolerant reset signal becomes active, preventing the system microcontroller, ASIC or peripheral from operating. The reset signal becomes inactive typically 200ms after the supply voltage exceeds the reset threshold level. Use With these two active high and low reset signals, the interface to microcontrollers and other ICs is very simple. In addition, RESET pin or separate input, MR can be used as push button input for manual reset function. On-chip, 2K-bit EEPROM memory Features a 16-byte page. In addition, hardware data protection provides a VCC detection circuit to prevent VCC from falling below the reset threshold when writing to memory, or until VCC reaches the reset threshold at power-on. Software packages available include an 8-pin DIP, 8-lead SOIC, 8-lead TSSOP, 8-lead TDFN and 8-lead MSOP. TDFN package thickness is 0.8mm max. TDFN package footprint options are 3x3mm.