DS1345W
3.3V 1024k Nonvolatile SRAM
with Battery Monitor
www.maxim-ic.com
FEATURES
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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
A15
A16
RST
V
CC
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
GND V
BAT
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
NC
NC
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
34-Pin PowerCap Module (PCM)
(Uses DS9034PC PowerCap)
PIN DESCRIPTION
A0-A16
DQ0-DQ7
CE
WE
OE
RST
BW
V
CC
GND
NC
- Address Inputs
- Data In/Data Out
- Chip Enable
- Write Enable
- Output Enable
- Reset Output
- Battery Warning Output
- Power (+3.3 Volts)
- Ground
- 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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DALLAS [ DALLAS SEMICONDUCTOR ]
