onsemi CAT1023WI-30-GT3

The CAT1021, CAT1022, and CAT1023 are complete memory and supervisory solutions for microcontroller-based systems. A 2k-bit I²C EEPROM and a system power monitor with undervoltage protection are integrated in low-power CMOS technology. The memory interface operates via a 400 kHz I²C bus.

The CAT1021 and CAT1023 provide a precision VCC sensing circuit and two open-drain outputs: one (RESET) driven high and the other (RESET) driven low whenever VCC falls below the reset threshold voltage. The CAT1022 has only the RESET output and no write-protect input. The CAT1021 also includes a write-protect input (WP). When WP is connected to a logic high level, write operations are disabled.

All supervisors feature a 1.6-second watchdog timer circuit that resets the system to a known state if a software or hardware failure causes the system to halt or "hang." For the CAT1021 and CAT1022, the watchdog timer monitors the SDA signal. The CAT1023 has a dedicated watchdog timer interrupt input pin WDI.

The power monitor and reset circuit protect the memory and system controller during power-up/power-down and under undervoltage conditions. Five reset threshold voltages support 5 V, 3.3 V, and 3 V systems. If the supply voltage falls outside the tolerance range, the reset signal becomes active, preventing the system microcontroller, ASIC, or peripherals from operating. The reset signal typically becomes inactive 200 ms after the supply voltage exceeds the reset threshold level. The availability of both active-high and active-low reset signals simplifies interfacing with microcontrollers and other ICs. In addition, the RESET pin or a separate input MR can be used as a pushbutton input for manual reset functionality.

The on-chip 2k-bit EEPROM features 16-byte pages. Hardware data protection is provided by the VCC sensing circuit, which prevents writes to the memory when VCC falls below the reset threshold or when VCC reaches the reset threshold during power-up.

Available packages include surface-mount 8-pin SOIC, 8-pin TSSOP, 8-pin TDFN, and 8-pin MSOP. The TDFN package has a maximum thickness of 0.8 mm. The TDFN package pitch option is 3 x 3 mm.

• Memory and supervisory solutions for microcontroller systems
• Power supply voltage monitoring for 5 V, 3.3 V, and 3 V systems
• System power monitoring to prevent data corruption during power-up/power-down and undervoltage conditions
• Manual reset input
• Write-protect input (CAT1021)
• Industrial and extended temperature range
• 8-pin SOIC, TSSOP, MSOP, or TDFN (3 x 3 mm) package