Supervisory Circuits with I2C Serial 2k-bit CMOS EEPROM and Manual Reset FEATURES
s Precision power supply voltage monitor s 16-Byte page write buffer
s 1,000,000 Program/Erase cycles s Manual reset input s 100 year data retention s 8-pin DIP, SOIC, TSSOP, MSOP & TDFNDESCRIPTION
voltages support 5V, 3.3V and 3V 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 The CAT1025 provides a precision VCC sense circuit RESET pin or a separate input, MR, can be used as an input and two open drain outputs: one (RESET) drives high for push-button manual reset capability. and the other (RESET) drives low whenever VCC falls below the reset threshold voltage. The CAT1025 also The CAT1024/25 memory features a 16-byte page. In has a Write Protect input (WP). Write operations are addition, hardware data protection is provided by a VCC sense circuit that prevents writes to memory whenever VCC disabled WP is connected to a logic high. falls below the reset threshold or until VCC reaches the reset The CAT1024 also provides a precision VCC sense threshold during power up. circuit, but has only a RESET output and does not have Available packages include an 8-pin DIP and a surface a Write Protect input. mount 8-pin SO, 8-pin TSSOP, 8-pin TDFN and 8-pin MSOP The power supply monitor and reset circuit protect packages. The TDFN package thickness is 0.8mm maximum. memory and system controllers during power up/down TDFN footprint options are or 3x4.9mm (MSOP pad and against brownout conditions. Five reset threshold layout). The CAT1024 and CAT1025 are complete memory and supervisory solutions for microcontroller-based systems. A 2k-bit serial EEPROM memory and a system power supervisor with brown-out protection are integrated together in low power CMOS technology. Memory interface is via 400kHz I2C bus.DIP Package (P, L) SOIC Package (S, V) TSSOP Package (U, Y) MSOP Package (R, Z)
(Bottom View) (Bottom View) TDFN Package: x 3mm TDFN Package: 4.9mm 0.8mm maximum height ZD2) 0.8mm maximum height (RD4, ZD4)2004 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice
EXTERNAL LOAD DOUT ACK VCC VSS WORD ADDRESS BUFFERS COLUMN DECODERS SENSE AMPS SHIFT REGISTERS
HIGH VOLTAGE/ TIMING CONTROL RESET Controller Precision MR
No Connect Active Low Reset Input/Output Ground Serial Data/Address Clock Input Active High Reset Output (CAT1025 only) Power Supply Write Protect (CAT1025 only) Manual Reset Input
RESET/RESET: RESET OUTPUTS (RESET CAT1025 Only) These are open drain pins and RESET can be used as a manual reset trigger input. By forcing a reset condition on the pin the device will initiate and maintain a reset condition. The RESET pin must be connected through a pull-down resistor, and the RESET pin must be connected through a pull-up resistor. SDA: SERIAL DATA ADDRESS The bidirectional serial data/address pin is used to transfer all data into and out of the device. The SDA pin is an open drain output and can be wire-ORed with other open drain or open collector outputs. SCL: SERIAL CLOCK Serial clock input. MR: MANUAL RESET INPUT Manual Reset input is a debounced input that can be connected to an external source for Manual Reset. Pulling the MR input low will generate a Reset condition. Reset outputs are active while MR input is low and for the reset timeout period after MR returns to high. The input has an internal pull-up resistor. WP (CAT1025 Only): WRITE PROTECT INPUT When tied to VSS or left unconnected write operations to the entire array are allowed. When tied to VCC, the entire array is protected. This input has an internal pull down resistor.
Device Manual Reset Input Pin Watchdog Monitor Pin SDA WDI Write Protection Pin Independent Auxiliary Voltage Sense RESET: Active High and LOW EEPROM
For supervisory circuits with embedded 16k EEPROM, please refer to the CAT1161, CAT1162 and CAT1163 data sheets.