BQ4017_14 Datasheet, PDF (1/14 Pages) Texas Instruments – 2048Kx8 Nonvolatile SRAM

Not Recommended for new Designs
bq4017/bq4017Y
2048Kx8 Nonvolatile SRAM
Features
➤ Data retention in the absence of
power
➤ Automatic write-protection dur-
ing power-up/power-down cycles
➤ Conventional SRAM operation;
unlimited write cycles
➤ 5-year minimum data retention
in absence of power
➤ Battery internally isolated until
power is applied
General Description
The CMOS bq4017 is a nonvolatile
16,777,216-bit static RAM organized
as 2,097,152 words by 8 bits. The
integral control circuitry and lith-
ium energy source provide reliable
nonvolatility coupled with the un-
limited 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 write-protected to
prevent an inadvertent write opera-
tion.
At this time the integral energy
source is switched on to sustain the
memory until after VCC returns valid.
The bq4017 uses extremely low
standby current CMOS SRAMs, cou-
pled with small lithium coin cells to
provide nonvolatility without long
write-cycle times and the write-cycle
limitations associated with EE-
PROM.
The bq4017 has the same interface
as industry-standard SRAMs and
requires no external circuitry.
Pin Connections
NC 1
A20 2
A18 3
A16 4
A14 5
A12 6
A7 7
A6 8
A5 9
A4 10
A3 11
A2 12
A1 13
A0 14
DQ0 15
DQ1 16
DQ2 17
VSS 18
36 VCC
35 A19
34 NC
33 A15
32 ^A17
31 WE
30 ^A13
29 ^A8
28 A9
27 ^A11
26 OE
25 ^A10
24 CE
23 DQ7
22 DQ6
21 DQ5
20 DQ4
19 DQ3
36-Pin DIP Module
PN401701.eps
Pin Names
A0–A20 Address inputs
DQ0–DQ7 Data input/output
CE
Chip enable input
OE
Output enable input
WE
Write enable input
VCC
Supply voltage input
VSS
Ground
NC
No connect
Block Diagram
Selection Guide
Part
Number
bq4017MC -70
Maximum
Access
Time (ns)
70
Negative
Supply
Tolerance
-5%
Part
Number
bq4017YMC -70
Maximum
Access
Time (ns)
70
Negative
Supply
Tolerance
-10%
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