BQ2205LYPWR Datasheet, PDF (1/14 Pages) Texas Instruments – POWER MONITORING AND SWITCHING CONTROLLER FOR 3.3-V SRAM

bq2205LY
SLUS581 − FEBRUARY 2004
POWER MONITORING AND SWITCHING CONTROLLER
FOR 3.3ĆV SRAM
FEATURES
D Power Monitoring and Switching for
Non-Volatile Control of SRAMs
D Input Decoder Allows Control of 1 or 2 Banks
of SRAM
D Write-Protect Control
D 3-V Primary Cell Input
D 3.3-V Operation
D Reset Output for System Power-On Reset
D Less than 20-ns Chip Enable Propagation
Delay
D Small 16-Lead TSSOP Package
APPLICATIONS
D NVSRAM Modules
D Point-of-Sale Systems
D Facsimile, Printers and Photocopiers
D Internet Appliances
D Servers
D Medical Instrumentation and Industrial
Products
DESCRIPTION
The CMOS bq2205 SRAM non-volatile controller
with reset provides all the necessary functions for
converting one or two banks of standard CMOS
SRAM into non-volatile read/write memory.
A precision comparator monitors the 3.3-V VCC
input for an out-of-tolerance condition. When
out-of-tolerance is detected, the two conditioned
chip-enable outputs are forced inactive to
write-protect both banks of SRAM.
Power for the external SRAMs, VOUT, is switched
from the VCC supply to the battery-backup supply
as VCC decays. On a subsequent power-up, the
VOUT supply is automatically switched from the
backup supply to the VCC supply. The external
SRAMs are write-protected until a power-valid
condition exists. The reset output provides
power-fail and power-on resets for the system.
During power-valid operation, the input decoder, A,
selects one of two banks of SRAM.
Main Supply
VDC
GND
Backup Supply
VDC
GND
From Address
Selector
bq2205LYPW
12 VCC
BW 15
1A
RST 16
11 CE
VOUT 13
9 BCP
4 VSS
5 VSS
8 ^VSS
CECON1 ₁₀
CECON2 ₁₄
VCC
To Microprocessor
VCC
VCC
CE
SRAM Bank 1
VCC
VCC
CE
SRAM Bank 2
Pushbutton
Reset
(Optional)
UDG−03129
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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Copyright  2004, Texas Instruments Incorporated
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