Overview

The Cypress CY14C256I/CY14B256I/CY14E256I combines a 256-Kbit nvSRAM

[1] with a full-featured RTC in a monolithic integrated circuit with serial I2C interface. The memory is organized as 64 K words of 8 bits each. The embedded nonvolatile elements incorporate the QuantumTrap technology, creating the world’s most reliable nonvolatile memory. The SRAM provides infinite readand write cycles, while the QuantumTrap cells provide highly reliable nonvolatile storage of data. Data transfers from SRAM to the nonvolatile elements

(STORE operation) takes place automatically at power-down. On power-up, data is restored to the SRAM from the nonvolatile memory (RECALL operation). The STORE and RECALL operations can also be initiated by the user through I2C commands.

Features

■256-Kbit nonvolatile static random access memory (nvSRAM)

❐Internally organized as 32 K × 8

❐STORE to QuantumTrap nonvolatile elements initiated

automatically on power-down (AutoStore) or by using I2C command (Software STORE) or HSBpin (Hardware STORE)

❐RECALL to SRAM initiated on power-up (Power-Up RECALL) or by I2C command (Software RECALL)

❐Automatic STORE on power-down with a small capacitor

■High reliability

❐Infinite read, write, and RECALL cycles

❐1 million STORE cycles to QuantumTrap

❐Data retention: 20 years at 85 °C

■Real Time Clock (RTC)

❐Full-featured RTC

❐Watchdog timer

❐Clock alarm with programmable interrupts

❐Backup power fail indication

❐Square wave output with programmable frequency (1 Hz, 512 Hz, 4096 Hz, 32.768 kHz)

❐Capacitor or battery backup for RTC

❐Backup current of 0.45 µA (typical)

■High-speed I2C interface

❐Industry standard 100 kHz and 400 kHz speed

❐Fast mode Plus 1 MHz speed

❐High speed: 3.4 MHz

❐Zero cycle delay reads and writes

■Write protection

❐Hardware protection using Write Protect (WP) pin

❐Software block protection for one-quarter, one-half, or entire array

■I2C access to special functions

❐Nonvolatile STORE/RECALL

❐8-byte serial number

❐Manufacturer ID and Product ID

❐Sleep mode

■Low power consumption

❐Average active current of 1 mA at 3.4 MHz operation

❐Average standby mode current of 250 µA

❐Sleep mode current of 8 µA

■Industry standard configurations

❐Operating voltages:

• CY14C256I: VCC= 2.4 V to 2.6 V

• CY14B256I: VCC= 2.7 V to 3.6 V

• CY14E256I: VCC= 4.5 V to 5.5 V

❐Industrial temperature

❐16-pin small outline integrated circuit (SOIC) package

❐Restriction of hazardous substances (RoHS) compliant