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CAT1021, CAT1022, CAT1023 2 Supervisory Circuits with I C Serial 2k-bit CMOS EEPROM, Manual Reset and Watchdog Timer FEATURES DESCRIPTION Precision Power Supply Voltage Monitor The CAT1021, CAT1022 and CAT1023 are complete memory and supervisory solutions for microcontroller- 5 V, 3.3 V and 3 V systems based systems. A 2k-bit serial EEPROM memory and a Five threshold voltage options system power supervisor with brown-out protection are Watchdog Timer integrated together in low power CMOS technology. 2 Memory interface is via a 400 kHz I C bus. Active High or Low Reset Valid reset guaranteed at V = 1 V The CAT1021 and CAT1023 provide a precision V CC CC 2 sense circuit and two open drain outputs: one (RESET) 400 kHz I C Bus drives high and the other (RESET) drives low whenever 2.7 V to 5.5 V Operation V falls below the reset threshold voltage. The CC Low power CMOS technology CAT1022 has only a RESET output and does not have a Write Protect input. The CAT1021 also has a Write 16-Byte Page Write Buffer Protect input (WP). Write operations are disabled if WP Built-in inadvertent write protection is connected to a logic high. WP pin (CAT1021) All supervisors have a 1.6 second watchdog timer circuit 1,000,000 Program/Erase cycles that resets a system to a known state if software or a Manual Reset Input hardware glitch halts or hangs the system. For the CAT1021 and CAT1022, the watchdog timer monitors 100 year data retention the SDA signal. The CAT1023 has a separate watchdog Industrial and extended temperature ranges timer interrupt input pin, WDI. 8-pin DIP, SOIC, TSSOP, MSOP or TDFN The power supply monitor and reset circuit protect (3 x 3 mm foot-print) packages memory and system controllers during power up/down TDFN max height is 0.8 mm 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 push- button manual reset capability. For Ordering Information details, see page 19. The on-chip, 2k-bit EEPROM memory features a 16-byte page. In addition, hardware data protection is provided by a V sense circuit that prevents writes to memory CC whenever V falls below the reset threshold or until V CC CC reaches the reset threshold during power up. Available packages include an 8-pin DIP and surface mount 8-pin SO, 8-pin TSSOP, 8-pin TDFN and 8-pin MSOP packages. The TDFN package thickness is 0.8mm maximum. TDFN footprint options are 3 x 3mm. 2009 SCILLC. All rights reserved. 1 Doc. No. MD-3009 Rev. P Characteristics subject to change without notice