CAT1021, CAT1022, CAT1023 Supervisory Circuits with 2 EEPROM Serial 2k-bit I C Manual Reset and www.onsemi.com Watchdog Timer Description The CAT1021, CAT1022 and CAT1023 are complete memory and supervisory solutions for microcontrollerbased systems. A EEPROM 2 Serial 2kbit I C memory and a system power supervisor with SOIC8 TSSOP8 brownout protection are integrated together in low power CMOS 2 CASE 751BD CASE 948S technology. Memory interface is via a 400 kHz I C bus. The CAT1021 and CAT1023 provide a precision VCC sense circuit and two open drain outputs: one (RESET) drives high and the other (RESET) drives low whenever VCC falls below the reset threshold voltage. The CAT1022 has only a RESET output and does not have a MSOP8 TDFN8 Write Protect input. The CAT1021 also has a Write Protect input CASE 846AD CASE 511AL (WP). Write operations are disabled if WP is connected to a logic high. All supervisors have a 1.6 second watchdog timer circuit that resets a system to a known state if software or a hardware glitch halts or hangs the system. For the CAT1021 and CAT1022, the watchdog ORDERING INFORMATION timer monitors the SDA signal. The CAT1023 has a separate watchdog For Ordering Information details, see page 13. timer interrupt input pin, WDI. The power supply monitor and reset circuit protect memory and system controllers during power up/down and against brownout conditions. Five reset threshold voltages support 5 V, 3.3 V and 3 V systems. If power supply voltages are out of tolerance reset signals become active, preventing the system microcontroller, ASIC or peripherals from operating. Reset signals become inactive typically 200 ms after the supply voltage exceeds the reset threshold level. With both active high and low reset signals, interface to microcontrollers and other ICs is simple. In addition, the RESET pin or a separate input, MR, can be used as an input for pushbutton manual reset capability. The onchip, 2kbit EEPROM memory features a 16byte page. In addition, hardware data protection is provided by a VCC sense circuit that prevents writes to memory whenever VCC falls below the reset threshold or until VCC reaches the reset threshold during power up. Available packages include an surface mount 8pin SOIC, 8 pin TSSOP, 8 pin TDFN and 8pin MSOP packages. The TDFN package thickness is 0.8 mm maximum. TDFN footprint options are 3 x 3 mm. Features Precision Power Supply Voltage Monitor Builtin Inadvertent Write Protection 5 V, 3.3 V and 3 V Systems WP Pin (CAT1021) Five Threshold Voltage Options 1,000,000 Program/Erase Cycles Watchdog Timer Manual Reset Input Active High or Low Reset 100 Year Data Retention Valid Reset Guaranteed at VCC = 1 V Industrial and Extended Temperature Ranges 2 400 kHz I C Bus 8pin SOIC, TSSOP, MSOP or TDFN (3 x 3 mm 2.7 V to 5.5 V Operation Footprint) Packages Low Power CMOS Technology TDFN Max Height is 0.8 mm 16Byte Page Write Buffer These Devices are PbFree, Halogen Free/BFR Free and are RoHS Compliant Semiconductor Components Industries, LLC, 2011 1 Publication Order Number: May, 2018 Rev. 19 CAT1021/DCAT1021, CAT1022, CAT1023 Table 1. THRESHOLD VOLTAGE OPTION Part Dash Minimum Maximum Number Threshold Threshold 45 4.50 4.75 42 4.25 4.50 30 3.00 3.15 28 2.85 3.00 25 2.55 2.70 BLOCK DIAGRAM EXTERNAL LOAD SENSEAMPS D OUT SHIFT REGISTERS ACK V CC WORDADDRESS COLUMN V SS BUFFERS DECODERS START/STOP SDA LOGIC 2kbit EEPROM XDEC CONTROL WP LOGIC ( AT1021)C DATA IN STORAGE HIGHVOLTAGE/ TIMING CONTROL RESET Controller STATE COUNTERS SCL Precision SLAVE MR ADDRESS Vcc Monitor COMPARATORS WDI RESET (CAT1023) (CAT1021/23) RESET www.onsemi.com 2