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參數(shù)資料
| 型號： | BQ4015YMB-85 |
| 英文描述： | Avalanche Bridge Rectifiers |
| 中文描述： | NVRAM中（基于電池） |
| 文件頁數(shù)： | 2/13頁 |
| 文件大?。?/td> | 450K |
| 代理商： | BQ4015YMB-85 |
Functional Description
When power is valid, the bq4013/Y operates as a stan-
dard CMOS SRAM. During power-down and power-up
cycles, the bq4013/Y acts as a nonvolatile memory, auto-
matically protecting and preserving the memory con-
tents.
Power-down/power-up control circuitry constantly moni-
tors the V
CC
supply for a power-fail-detect threshold
V
PFD
. The bq4013 monitors for V
PFD
= 4.62V typical for
use in systems with 5% supply tolerance. The bq4013Y
monitors for V
PFD
= 4.37V typical for use in systems
with 10% supply tolerance.
When V
CC
falls below the V
PFD
threshold, the SRAM au-
tomatically write-protects the data. All outputs become
high impedance, and all inputs are treated as “don’t
care.”
If a valid access is in process at the time of
power-fail detection, the memory cycle continues to com-
pletion. If the memory cycle fails to terminate within
time t
WPT
,write-protection takes place.
As V
CC
falls past V
PFD
and approaches 3V, the control
circuitry switches to the internal lithium backup supply,
which provides data retention until valid V
CC
is applied.
When V
CC
returns to a level above the internal backup
cell voltage, the supply is switched back to V
CC
. After
V
CC
ramps above the V
PFD
threshold, write-protection
continues for a time t
CER
(120ms maximum) to allow for
processor stabilization. Normal memory operation may
resume after this time.
The internal coin cell used by the bq4013/Y has an ex-
tremely long shelf life and provides data retention for
more than 10 years in the absence of system power.
As shipped from Unitrode, the integral lithium cell of
the MA-type module is electrically isolated from the
memory. (Self-discharge in this condition is approxi-
mately 0.5% per year.) Following the first application of
V
CC
, this isolation is broken, and the lithium backup cell
provides data retention on subsequent power-downs.
2
bq4013/Y
OE
CE
BD-42
WE
Power
Lithium
Cell
Power-Fail
Control
128K x 8
SRAM
Block
CE
CON
V
CC
A
0
–A
16
DQ
0
–DQ
7
Block Diagram
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| BQ4845P | Fast Recovery Glass Passivated Rectifier Diodes |
| BQ4845S | Fast Recovery Glass Passivated Rectifier Diodes |
| BQ4845YP | Fast Recovery Glass Passivated Rectifier Diodes |
| BQ4845YS | Fast Recovery Glass Passivated Rectifier Diodes |
| BQ4847Y | Fast Recovery Glass Passivated Rectifier Diodes |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| BQ4015YMB-85N | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:NVRAM (Battery Based) |
| BQ4015YMS-120 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:512Kx8 Nonvolatile SRAM |
| BQ4015YMS-120N | 制造商:TI 制造商全稱:Texas Instruments 功能描述:512Kx8 Nonvolatile SRAM |
| BQ4015YMS-70 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:512Kx8 Nonvolatile SRAM |
| BQ4015YMS-70N | 制造商:TI 制造商全稱:Texas Instruments 功能描述:512Kx8 Nonvolatile SRAM |
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