Features: `Precision power supply voltage monitor
- 5V, 3.3V and 3V systems
- Five threshold voltage options
` Watchdog timer
` Active high or low reset
- Valid reset guaranteed at VCC = 1 V
` 400kHz I2C bus
`3.0V to 5.5V operation
`Low power CMOS technology
`16-Byte page write buffer
` Built-in inadvertent write protection
- WP pin (CAT1021)
` 1,000,000 Program/Erase cycles
`Manual reset input
` 100 year data retention
`8-pin DIP, SOIC, TSSOP, MSOP or TDFN (3 x 3 mm foot-print) packages
- TDFN max height is 0.8mm
`Industrial and extended temperature rangesPinout
SpecificationsTemperature Under Bias ...................... 55 to +125
Storage Temperature .......................... 65 to +150
Voltage on any Pin with
Respect to Ground(1) ................. 2.0 V to VCC + 2.0 V
VCC with Respect to Ground ................. 2.0V to 7.0 V
Package Power Dissipation
Capability (TA = 25) .......................................... 1.0 W
Lead Soldering Temperature (10 secs) ............... 300
Output Short Circuit Current(2) ........................ 100 mA
Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions outside of those listed in the operational sections of this specification is not implied. Exposure to any absolute maximum rating for extended periods may affect device performance and reliability.
Note:
(1) The minimum DC input voltage is 0.5V. During transitions, inputs may undershoot to 2.0V for periods of less than 20 ns. Maximum DC voltage on output pins is VCC +0.5V, which may overshoot to VCC +2.0V for periods of less than 20 ns.
(2) Output shorted for no more than one second. No more than
one output shorted at a time.Description
The CAT1021 is a complete memory and supervisory solution 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 a 400kHz I²C bus.
The CAT1021 provides 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 CAT1021 also has a Write Protect input (WP). Write operations are disabled if WP is connected to a logic high.
The supervisor CAT1021 has 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. The watchdog timer monitors the SDA signal.
The power supply monitor and reset circuitCAT1021 protect memory and system controllers during power up/down and against brownout conditions. Five reset threshold voltages support 5V, 3.3V and 3V systems. If power supply voltages CAT1021 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.
The on-chip, 2k-bit EEPROM memory features a 16-byte page. In addition,CAT1021 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.
CAT1021 Available packages include an 8-pin DIP, 8-pin SOIC, 8-pin TSSOP, 8-pin TDFN and 8-pin MSOP. The TDFN package thickness is 0.8mm maximum. TDFN footprint options are 3x3mm.
The CAT1021, CAT1022 and CAT1023 are complete memory and supervisory solutions for microcontrollerbased systems. A 2k-bit serial EEPROM memory and a system power supervisor with brown-out protection are integrated together in low power CMOS technology.
CAT1021 Memory interface is via a 400kHz I2C 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 VCCfalls below the reset threshold voltage. The CAT1022 has only a RESET output and does not have a Write Protect input. The CAT1021 also has a Write Protect input (WP). Write operations are disabled if WP is connected to a logic high.
All supervisors CAT1021 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 timer monitors the SDA signal. The CAT1023 has a separate watchdog timer interrupt input pin, WDI.
The power supply monitor and reset circuitCAT1021 protect memory and system controllers during power up/down and against brownout conditions. Five reset threshold 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 RESET pin or a separate input, MR, can be used as an input for push-button manual reset capability.
The on-chip, 2k-bit EEPROM memory features a 16-byte 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 8-pin DIP, 8-pin SOIC, 8-pin TSSOP, 8-pin TDFN and 8-pin MSOP. The CAT1021 TDFN package thickness is 0.8mm maximum. TDFN footprint options are 3x3mm.
CAT1021 Data Sheet
