Unlimited write cycles
Low-power CMOS
Read and write access times as fast as 70 ns
Lithium energy source is electrically
disconnected to retain freshness until power is
applied for the first time
Full ±10% VCC operating range (DS1230Y)
Optional ±5% VCC operating range
(DS1230AB)
Optional industrial temperature range of
-40°C to +85°C, designated IND
JEDEC standard 28-pin DIP package
New 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
NC
NC
NC
NC
V
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
GND
A14
A12
DQ0
DQ1
DQ2
GND
28-Pin ENCAPSULATED PACKAGE
CC
34-Pin POWERCAP MODULE (PCM)
1
2
A7
3
4
A6
A5
5
A4
6
A3
7
A2
8
A1
9
10
A0
11
12
13
14
740-mil EXTENDED
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
(USES DS9034PC POWERCAP)
GND
28
V
27
WE
26
25
24
23
22
21
20
19
18
17
16
15
V
BAT
8
9
11
OE
10
CE
DQ7
DQ6
DQ5
DQ4
DQ3
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
NC
NC
14
12
10
8
5
4
3
1
0
PIN DESCRIPTION
A0 - A14- Address Inputs
DQ0 - DQ7 - Data In/Data Out
CE - Chip Enable
WE - Write Enable
OE - Output Enable
V
- Power (+5V)
CC
GND - Ground
NC - No Connect
1 of 12111899
DS1230Y/AB
DESCRIPTION
The DS1230 256k Nonvolatile SRAMs are 262,144-bit, fully static, nonvolatile SRAMs organized as
32,768 words by 8 bits. Each NV SRAM has a self-contained lithium energy source and control circuitry
which constantly monitors VCC 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. DIP-package DS1230 devices can be used in place of existing 32k x 8 static
RAMs directly conforming to the popular bytewide 28-pin DIP standard. The DIP devices also match the
pinout of 28256 EEPROMs, allowing direct substitution while enhancing performance. DS1230 devices
in the Low Profile Module package are specifically designed for surface-mount applications. There is no
limit on the number of write cycles that can be executed and no additional support circuitry is required for
microprocessor interfacing.
READ MODE
The DS1230 devices execute a read cycle whenever WE (Write Enable) is inactive (high) and CE (Chip
Enable) and OE (Output Enable) are active (low). The unique address specified by the 15 address inputs
(A0 - A14) defines which of the 32,768 bytes of data is to be accessed. Valid data will be available to the
eight data output drivers within t
that CE and OE (Output Enable) access times are also satisfied. If OE and CE access times are not
satisfied, then data access must be measured from the later-occurring signal (CE or OE ) and the limiting
parameter is either tCO for CE or tOE for OE rather than address access.
(Access Time) after the last address input signal is stable, providin g
ACC
WRITE MODE
The DS1230 devices execute a write cycle whenever the WE and CE signals are active (low) after
address inputs are stable. The later-occurring falling edge of CE or WE will determine the start of the
write cycle. The write cycle is terminated by the earlier rising edge of CE or WE . All address inputs must
be kept valid throughout the write cycle. WE must return to the high state for a minimum recovery time
(tWR) before another cycle can be initiated. The OE control signal should be kept inactive (high) during
write cycles to avoid bus contention. However, if the output drivers are enabled (CE and OE active) then
WE will disable the outputs in t
from its falling edge.
ODW
DATA RETENTION MODE
The DS1230AB provides full functional capability for VCC greater than 4.75 volts and write protects by
4.5 volts. The DS1230Y provides full functional capability for V
protects by 4.25 volts. Data is maintained in the absence of VCC without any additional support circuitry.
The nonvolatile static RAMs constantly monitor VCC. Should the supply voltage decay, the NV SRAMs
automatically write protect themselves, all inputs become “don’t care,” and all outputs become highimpedance. As V
falls below approximately 3.0 volts, a power switching circuit connects the lithium
CC
energy source to RAM to retain data. During power-up, when VCC rises above approximately 3.0 volts
the power switching circuit connects external VCC to RAM and disconnects the lithium energy source.
Normal RAM operation can resume after V
exceeds 4.75 volts for the DS1230AB and 4.5 volts for the
CC
DS1230Y.
greater than 4.5 volts and write
CC
FRESHNESS SEAL
Each DS1230 device is shipped from Dallas Semiconductor with its lithium energy source disconnected,
guaranteeing full energy capacit y. When V
energy source is enabled for battery back-up operation.
is first applied at a level greater than 4.25 volts, the lithium
CC
2 of 12
DS1230Y/AB
PACKAGES
The DS1230 devices are available in two packages: 28-pin DIP and 34-pin PowerCap Module (PCM).
The 28-pin DIP integrates a lithium battery, an SRAM memory and a nonvolatile control function into a
single package with a JEDEC-standard, 600-mil DIP pinout. The 34-pin PowerCap Module integrates
SRAM memory and nonvolatile control along with contacts for connection to the lithium battery in the
DS9034PC PowerCap. The PowerCap Module package design allows a DS1230 PCM device to be
surface mounted without subjecting its lithium backup battery to destructive high-temperature reflow
soldering. After a DS1230 PCM is reflow soldered, a DS9034PC PowerCap is snapped on top of the
PCM to form a complete Nonvolatile SRAM module. The DS9034PC is keyed to prevent improper
attachment. DS1230 PowerCap Modules and DS9034PC PowerCaps are ordered separately and shipped
in separate containers. See the DS9034PC data sheet for further information.
ABSOLUTE MAXIMUM RATINGS*
Voltage on Any Pin Relative to Ground -0.3V to +7.0V
Operating Temperature 0°C to 70°C, -40°C to +85°C for IND parts
Storage Temperature -40°C to +70°C, -40°C to +85°C for IND parts
Soldering Temperature 260°C for 10 seconds
* This is a stress rating only and functional operation of the device at these or any other conditions
above those indicated in the operation sections of this specification is not implied. Exposure to
absolute maximum rating conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS (tA: See Note 10)
PARAMETERSYMBOLMINTYPMAXUNITSNOTES
DS1230AB Power Supply VoltageV
DS1230Y Power Supply VoltageV
Logic 1V
Logic 0V
CC
CC
IH
IL
4.755.05.25V
4.55.05.5V
2.2V
CC
V
0.00.8V
DC ELECTRICAL (VCC=5V ±=5% for DS1230AB)
CHARACTERISTICS (t
PARAMETERSYMBOLMINTYPMAXUNITSNOTES
Input Leakage CurrentI
I/O Leakage Current CE ≥ VIH ≤ V
Output Current @ 2.4VI
Output Current @ 0.4VI
Standby Current CE =2.2V
Standby Current CE =VCC-0.5V
CC
: See Note 10) (VCC=5V ±=10% for DS1230Y)
A
I
I
CCS1
I
CCS2
IL
IO
OH
OL
-1.0+1.0
-1.0+1.0
-1.0mA
2.0mA
5.010.0mA
3.05.0mA
µA
µA
Operating CurrentI
Write Protection Voltage (DS1230AB)V
Write Protection Voltage (DS1230Y)V
CCO1
TP
TP
3 of 12
85mA
4.504.624.75V
4.254.374.5V
DS1230Y/AB
CAPACITANCE (tA=25°C)
PARAMETERSYMBOLMINTYPMAXUNITSNOTES
Input CapacitanceC
Input/Output CapacitanceC
IN
I/O
510pF
510pF
AC ELECTRICAL (VCC=5V ±=5% for DS1230AB)
CHARACTERISTICS (t
DS1230AB-70
PARAMETERSYMBOL
Read Cycle
t
RC
Time
Access Timet
OE to Output
ACC
t
OE
Valid
CE to Output
t
CO
Valid
OE or CE to
t
COE
Output Active
Output High Z
t
OD
from
Deselection
DS1230Y-70
MINMAXMINMAXMINMAX
7085100ns
555 ns5
: See Note 10) (VCC=5V ±=10% for DS1230Y)
A
DS1230AB-85
DS1230Y-85
DS1230AB-100
DS1230Y-100
UNITSNOTES
7085100ns
354550ns
7085100ns
253035ns5
Output Hold
from Address
Change
Write Cycle
Time
Write Pulse
Width
Address Setup
Time
Write Recovery
Time
Output High Z
from WE
Output Active
from WE
Data Setup
Time
Data Hold
Time
t
t
WC
t
WP
t
AW
t
WR1
t
WR2
t
ODW
t
OEW
t
t
DH1
t
DH2
OH
DS
555 ns
7085100ns
556575ns3
000 ns
5
15
5
15
5
15
ns12
13
253035ns5
555 ns5
303540ns4
0
10
0
10
0
10
ns12
13
4 of 12
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