DS1249W

DS1249W 3.3V 2048kb Nonvolatile SRAM www.maxim-ic.com FEATURES § § § § § § § § 10 years minimum data retention in the absence of external power Data is automatically protected during power loss Unlimited write cycles Low-power CMOS operation Read and write access times as fast as 100ns Lithium energy source is electrically disconnected to retain freshness until power is applied for the first time Optional industrial (IND) temperature range of -40°C to +85°C JEDEC standard 32-pin DIP package PIN ASSIGNMENT NC A16 A14 A12 A7 A6 A5 A4 A3 A2 A1 A0 DQ0 DQ1 DQ2 GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 VCC A15 A17 WE A13 A8 A9 A11 OE A10 CE DQ7 DQ6 DQ5 DQ4 DQ3 32-Pin Encapsulated Package 740mil Extended PIN DESCRIPTION A0–A17 DQ0–DQ7 CE WE OE VCC GND NC - Address Inputs - Data In/Data Out - Chip Enable - Write Enable - Output Enable - Power (+3.3V) - Ground - No Connect DESCRIPTION The DS1249W 2048kb nonvolatile (NV) SRAMs are 2,097,152-bit, fully static, NV SRAMs organized as 262,144 words by 8 bits. Each NV SRAM has a self-contained lithium energy source and control circuitry that constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent data corruption. There is no limit on the number of write cycles that can be executed, and no additional support circuitry is required for micropro...