DS1345W Datasheet, PDF (1/12 Pages) Dallas Semiconductor – 3.3V 1024k Nonvolatile SRAM with Battery Monitor

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DS1345W
3.3V 1024k Nonvolatile SRAM
with Battery Monitor
FEATURES
§ 10 years minimum data retention in the
absence of external power
§ Data is automatically protected during power
loss
§ Power supply monitor resets processor when
V_CC power loss occurs and holds processor in
reset during V_CC ramp-up
§ Battery monitor checks remaining capacity
daily
§ Read and write access times as fast as 100 ns
§ Unlimited write cycle endurance
§ Typical standby current 50 µA
§ Upgrade for 128k x 8 SRAM, EEPROM or
Flash
§ Lithium battery is electrically disconnected to
retain freshness until power is applied for the
first time
§ Optional industrial temperature range of
-40°C to +85°C, designated IND
§ PowerCap Module (PCM) package
- Directly surface-mountable module
- Replaceable snap-on PowerCap provides
lithium backup battery
- Standardized pinout for all nonvolatile
SRAM products
- Detachment feature on PowerCap allows
easy removal using a regular screwdriver
PIN ASSIGNMENT
BW
1
A15
2
A16
3
RST
4
VCC
5
WE
6
OE
7
CE
8
DQ7
9
DQ6
10
DQ5
11
DQ4
12
DQ3
13
DQ2
14
DQ1
15
DQ0
16
GND
17
GND VBAT
34
NC
33
NC
32
A14
31
A13
30
A12
29
A11
28
A10
27
A9
26
A8
25
A7
24
A6
23
A5
22
A4
21
A3
20
A2
19
A1
18
A0
34-Pin PowerCap Module (PCM)
(Uses DS9034PC PowerCap)
PIN DESCRIPTION
A0-A16
- Address Inputs
DQ0-DQ7
- Data In/Data Out
CE
- Chip Enable
WE
- Write Enable
OE
- Output Enable
RST
- Reset Output
BW
- Battery Warning Output
V_CC
GND
- Power (+3.3 Volts)
- Ground
NC
- No Connect
DESCRIPTION
The DS1345W 3.3V 1024k Nonvolatile SRAM is a 1,048,576-bit, fully static, nonvolatile SRAM
organized as 131,072 words by 8 bits. Each NV SRAM has a self-contained lithium energy source and
control circuitry, which constantly monitors V_CC for an out-of-tolerance condition. When such a condition
occurs, the lithium energy source is automatically switched on and write protection is unconditionally
enabled to prevent data corruption. Additionally, the DS1345W has dedicated circuitry for monitoring the
status of V_CC and the status of the internal lithium battery. DS1345W devices in the PowerCap Module
package are directly surface mountable and are normally paired with a DS9034PC PowerCap to form a
complete Nonvolatile SRAM module. The devices can be used in place of 128k x 8 SRAM, EEPROM or
Flash components.
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