bq4011/bq4011Y
32Kx8 Nonvolatile SRAM
At t his tim e t he integr a l ener gy
Features
➤ Data retention in the absence of
General Description
source is switched on to sustain the
memory until after VCC returns valid.
The CMOS bq4011 is a nonvolatile
262,144-bit static RAM organized as
32,768 words by 8 bits. The integral
control circuitry and lithium energy
source provide reliable nonvolatility
coupled with th e unlim ited write
cycles of standard SRAM.
power
The bq4011 uses an extremely low
s t a n dby cu r r en t CMOS SRAM,
coupled with a small lithium coin cell
to provide nonvolatility without long
write-cycle times and the write-cycle
limitations associated with EEPROM.
➤ Automatic write-protection
during power-up/power-down
cycles
➤ Industry-standard 28-pin 32K x
8 pinout
Th e con tr ol cir cu it r y con s ta n t ly
monitors the single 5V supply for an
ou t -of-t oler a n ce con dit ion . Wh en
VCC falls out of tolerance, the SRAM
is unconditionally write-protected to
prevent inadvertent write operation.
The bq4011 requires no external cir-
cuitry and is socket-compatible with
industry-standard SRAMs and most
EPROMs and EEPROMs.
➤ Conventional SRAM operation;
unlimited write cycles
➤ 10-year minimum data retention
in absence of power
➤ Battery internally isolated until
power is applied
Pin Connections
Pin Names
Block Diagram
A0 –A14
Address inputs
DQ0–DQ7 Data input/output
CE
Chip enable input
Output enable input
Write enable input
+5 volt supply input
Ground
OE
WE
VCC
VSS
Selection Guide
Maximum
Access
Negative
Supply
Maximum
Access
Negative
Supply
Part
Part
Number
Time (ns)
Tolerance
Number
Time (ns)
Tolerance
bq4011Y-70
70
-10%
-10%
-10%
-10%
bq4011 -100
bq4011Y -100
bq4011Y -150
bq4011Y -200
100
150
200
-5%
-5%
-5%
100
150
200
bq4011 -150
bq4011 -200
Aug. 1993 C
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