BQ4024

www.DataSheet4U.com bq4024/bq4024Y 128Kx16 Nonvolatile SRAM Features ® Data retention in the absence of power ® Automatic write-protection during power-up/power-down cycles ® Industry-standard 40-pin 128K x 16 pinout ® Conventional SRAM operation; unlimited write cycles ® 10-year minimum data retention in absence of power ® Battery internally isolated until power is applied General Description The CMOS bq4024 is a nonvolatile 2,097,152-bit static RAM organized as 131,072 words by 16 bits. The integral control circuitry and lithium energy source provide reliable nonvolatility coupled with the unlimited write cycles of standard SRAM. The control circuitry constantly monitors the single 5V supply for an out-of-tolerance condition. When VCC falls out of tolerance, the SRAM is unconditionally writeprotected to prevent an inadvertent write operation. At this time the integral energy source is switched on to sustain the memory until after VCC returns valid. The bq4024 uses extremely low standby current CMOS SRAMs, coupled with small lithium coin cells to provide nonvolatility without long write-cycle times and the write-cycle limitations associated with EEPROM. The bq4024 requires no external circuitry and is compatible with the industry-standard 2Mb SRAM pinout. Pin Connections NC CE DQ15 DQ14 DQ13 DQ12 DQ11 DQ10 DQ9 DQ8 VSS DQ7 DQ6 DQ5 DQ4 DQ3 DQ2 DQ1 DQ0 OE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 VCC WE A1...