U635H64 Datasheet | Simtek

Features - - - - - - - - - - - - - - - - High-performance CMOS nonvolatile static RAM 8192 x 8 bits 25, 35 and 45 ns Access Times 12, 20 and 25 ns Output Enable Access Times ICC = 15 m A at 200 ns Cycle Time Automatic STORE to EEPROM on Power Down using system capacitance Software initiated STORE (STORE Cycle Time < 10 ms) Automatic STORE Timing 105 STORE cycles to EEPROM 10 years data retention in EEPROM Automatic RECALL on Power Up Software RECALL Initiation (RECALL Cycle Time < 20 μs) Unlimited RECALL cycles from EEPROM Single 5 V ± 10 % Operation Operating temperature ranges: 0 to 70 °C -40 to 85 °C QS 9000 Quality Standard ESD characterization according MIL STD 883C M3015.7-HBM (classification see IC Code Numbers) - - Ro HS pliance and Pb- free Packages: PDIP28 (600 mil) SOP28 (330 mil) Description The U635H64 has two separate modes of operation: SRAM mode and nonvolatile mode. In SRAM mode, the memory operates as an ordinary static RAM. In nonvolatile operation, data is transferred in parallel from SRAM to EEPROM or from EEPROM to SRAM. In this mode SRAM functions are disabled. The U635H64 is a fast static RAM (25, 35, 45 ns), with a nonvolatile electrically erasable PROM (EEPROM) element incorporated in each static memory cell. The SRAM can be read and written an unlimited number of times, while independent nonvolatile data resides in EEPROM. Data transfers from the SRAM to the EEPROM (the STORE operation) take place automatically upon power down using charge stored in system capacitance. Transfers from the EEPROM to the SRAM (the RECALL operation) take place automatically on power up. The U635H64 bines the high performance and ease of use of a fast SRAM with nonvolatile data integrity. STORE cycles also may be initiated under user control via a software sequence. Once a STORE cycle is initiated, further input or output are disabled until the cycle is pleted. Because a sequence of addresses is used for STORE initiation, it is important that no other read...