—Store Cycles: 1,000,000
—Data Retention: 100 Years
• Low Power Consumption
—Active: 40mA Max.
—Standby: 100µA Max.
• Infinite Array Recall, RAM Read and Write Cycles
• Nonvolatile Store Inhibit: V
= 3.5V Typical
CC
• Fully TTL and CMOS Compatible
• JEDEC Standard 18-Pin 300-mil DIP
• 100% Compatible with X2212
DESCRIPTION
The X22C12 is a 256 x 4 CMOS NOVRAM featuring a
high-speed static RAM overlaid bit-for-bit with a nonvolatile E2PROM. The NOVRAM design allows data to
be easily transferred from RAM to E2PROM (STORE)
and from E2PROM to RAM (RECALL). The STORE
operation is completed within 5ms or less and the
RECALL is completed within 1µs.
Xicor NOVRAMs are designed for unlimited write operations to the RAM, either RECALLs from E2PROM or
writes from the host. The X22C12 will reliably endure
1,000,000 STORE cycles. Inherent data retention is
greater than 100 years.
PIN DESCRIPTIONS AND DEVICE OPERATION
Addresses (A0–A7)
The address inputs select a 4-bit memory location
during a read or write operation.
Chip Select (CS)
The Chip Select input must be LOW to enable read or
write operations with the RAM array. CS HIGH will place
the I/O pins in the high impedance state.
Write Enable (WE)
The Write Enable input controls the I/O buffers, determining whether a RAM read or write operation is enabled. When CS is LOW and WE is HIGH, the I/O pins
will output data from the selected RAM address locations. When both CS and WE are LOW, data presented
at the I/O pins will be written to the selected address
location.
Data In/Data Out (I/O1–I/O4)
Data is written to or read from the X22C12 through the
I/O pins. The I/O pins are placed in the high impedance
state when either CS is HIGH or during either a store or
recall operation.
STORE
The STORE input, when LOW, will initiate the transfer of
the entire contents of the RAM array to the E2PROM
array. The WE and RECALL inputs are inhibited during
the store cycle. The store operation is completed in 5ms
or less.
A store operation has priority over RAM read/write
operations. If STORE is asserted during a read operation, the read will be discontinued. If STORE is asserted
during a RAM write operation, the write will be immediately terminated and the store performed. The data at
the RAM address that was being written will be unknown
in both the RAM and E2PROM arrays.
RECALL
The RECALL input, when LOW, will initiate the transfer
of the entire contents of the E2PROM array to the RAM
array. The transfer of data will be completed in 1µs or
less.
An array recall has priority over RAM read/write operations and will terminate both operations when RECALL
is asserted. RECALL LOW will also inhibit the STORE
input.
Automatic Recall
Upon power-up the X22C12 will automatically recall
data from the E2PROM array into the RAM array.
Write Protection
The X22C12 has three write protect features that are
employed to protect the contents of the nonvolatile
memory.
•VCC Sense—All functions are inhibited when VCC is
<3.5V typical.
• Write Inhibit—Holding either STORE HIGH or
RECALL LOW during power-up or power-down will
prevent an inadvertent store operation and E2PROM
data integrity will be maintained.
• Noise Protection—A STORE pulse of typically less
than 20ns will not initiate a store cycle.
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only and the functional operation of
the device at these or any other conditions above those
indicated in the operational sections of this specification is
not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
LHHHOutput DataRead RAM
LLHHInput Data HighWrite “1” RAM
LLHHInput Data LowWrite “0” RAM
XHLHOutput High ZArray Recall
HXLHOutput High ZArray Recall
XHHLOutput High ZNonvolatile Store
HXHLOutput High ZNonvolatile Store
ENDURANCE AND DATA RETENTION
ParameterMin.Units
Endurance100,000Data Changes Per Bit
Store Cycles1,000,000Store Cycles
Data Retention100Years
(3)
(4)
(4)
3817 PGM T05.1
3817 PGM T06
POWER-UP TIMING
SymbolParameterMax.Units
(5)
t
PUR
(5)
t
PUW
EQUIVALENT A.C. LOAD CIRCUIT
Power-up to Read Operation100µs
Power-up to Write or Store Operation5ms
A.C. CONDITIONS OF TEST
5V
Input Pulse Levels0V to 3V
Input Rise and
Fall Times10ns
919Ω
OUTPUT
497Ω
Notes: (3) Chip is deselected but may be automatically completing a store cycle.
(4) STORE = LOW is required only to initiate the store cycle, after which the store cycle will be automatically completed
(e.g. STORE = X).
(5) t
and t
PUR
parameters are periodically sampled and not 100% tested.
are the delays required from the time VCC is stable until the specified operation can be initiated. These
PUW
100pF
3815 FHD F09.1
Input and Output
Timing Levels1.5V
3817 PGM T07
3817 PGM T04.1
4
Page 5
X22C12
CS
ADDRESS
t
RC
t
CO
t
A
t
HZ
t
LZ
DATA I/O
t
OH
DATA VALID
A.C. CHARACTERISTICS (Over the recommended operating conditions, unless otherwise specified.)
Read Cycle Limits
SymbolParameterMin.Max.Units
t
RC
t
AA
t
CO
t
OH
(6)
t
LZ
(6)
t
HZ
Read Cycle
Read Cycle Time150ns
Access Time150ns
Chip Select to Output Valid150ns
Output Hold from Address Change0ns
Chip Select to Output in Low Z0ns
Chip Deselect to Output in High Z50ns
3817 PGM T08
Note: (6) tLZ min. and tHZ min. are periodically sampled and not 100% tested.
3817 FHD F03
5
Page 6
X22C12
Write Cycle Limits
SymbolParameterMin.Max.Units
t
WC
t
CW
t
AS
t
WP
t
WR
t
DW
t
DH
t
WZ
t
OW
Write Cycle
ADDRESS
CS
WE
DATA IN
Write Cycle Time150ns
Chip Select to End of Write90ns
Address Setup Time0ns
Write Pulse Width90ns
Write Recovery Time0ns
Data Valid to End of Write40ns
Data Hold Time0ns
Write Enable to Output in High Z50ns
Output Active from End of Write0ns
3817 PGM T09.1
t
WC
t
CW
t
AS
t
WP
t
DW
DATA VALID
t
DH
t
WR
DATA OUT
Early Write Cycle
ADDRESS
CS
WE
DATA IN
DATA OUT
t
DH
t
OW
t
3817 FHD F04
WR
3817 FHD F05
t
WZ
t
WC
t
CW
t
AS
HIGH Z
t
WP
t
DW
DATA VALID
6
Page 7
X22C12
Recall Cycle Limits
SymbolParameterMin.Max.Units
t
RCC
(7)
t
RCP
t
RCZ
t
ORC
t
ARC
Recall Cycle
ADDRESS
RECALL
CS
DATA I/O
Array Recall Time1µs
Recall Pulse Width90ns
Recall to Output in High Z50ns
Output Active from End of Recall0ns
Recalled Data Access Time from End of Recall120ns
3817 PGM T10
t
RCC
t
RCP
t
RCZ
t
ORC
t
ARC
3817 FHD F06
Note: (7) RECALL rise time must be less than 1µs.
7
Page 8
X22C12
Store Cycle Limits
SymbolParameterMin.Max.Units
t
STC
t
STP
t
STZ
t
OST
Store Cycle Limits
STORE
DATA I/O
Internal Store Time5ms
Store Pulse Width90ns
Store to Output in High Z50ns
Output Active from End of Store0ns
3817 PGM T11
t
STC
t
STP
t
STZ
HI Z
t
OST
3817 FHD F07
SYMBOL TABLE
WAVEFORM
INPUTS
OUTPUTS
Must be
steady
May change
from LOW
to HIGH
May change
from HIGH
to LOW
Don’t Care:
Changes
Allowed
N/A
Will be
steady
Will change
from LOW
to HIGH
Will change
from HIGH
to LOW
Changing:
State Not
Known
Center Line
is High
Impedance
8
Page 9
X22C12
PIN 1 INDEX
18-LEAD PLASTIC DUAL IN-LINE PACKAGE TYPE P
0.915 (23.24)
0.894 (22.71)
0.270 (6.86)
0.250 (6.35)
PIN 1
0.800 (20.32)
REF.
0.060 (1.52)
0.050 (1.27)
SEATING
PLANE
0.140 (3.56)
0.120 (3.05)
0.110 (2.79)
0.090 (2.29)
TYP. 0.010 (0.25)
0.070 (1.78)
0.050 (1.27)
0.325 (8.26)
0.300 (7.62)
0.020 (0.51)
0.016 (0.41)
0°
15°
NOTE:
1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
2. PACKAGE DIMENSIONS EXCLUDE MOLDING FLASH
0.165 (4.19)
0.130 (3.30)
0.025 (0.51)
0.005 (0.13)
3926 FHD F02
9
Page 10
X22C12
18-LEAD HERMETIC DUAL IN-LINE PACKAGE TYPE D
0.960 (24.38)
––
0.310 (7.87)
0.220 (5.59)
SEATING
PLANE
0.150 (3.81) MIN.
PIN 1
0.200 (5.08)
0.125 (3.18)
0.110 (2.79)
0.090 (2.29)
TYP. 0.100 (2.54)
0.015 (0.38)
0.008 (0.20)
0.800 (20.32)
REF.
0.065 (1.65)
0.038 (0.97)
TYP. 0.060 (1.52)
0.320 (8.13)
0.290 (7.37)
TYP. 0.311 (7.90)
0.005 (0.13) MIN.
0.098 (2.49)
––
0.200 (5.08)
––
0.070 (1.78)
0.015 (0.38)
0.023 (0.58)
0.014 (0.36)
TYP. 0.018 (0.46)
0°
15°
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
3926 FHD F06
10
Page 11
X22C12
20-LEAD PLASTIC SMALL OUTLINE GULL WING PACKAGE TYPE S
0° – 8°
PIN 1 INDEX
(4X) 7°
0.050 (1.27)
0.010 (0.25)
0.020 (0.50)
PIN 1
0.015 (0.40)
0.050 (1.27)
X 45°
0.014 (0.35)
0.020 (0.50)
0.496 (12.60)
0.508 (12.90)
0.007 (0.18)
0.011 (0.28)
0.420"
0.290 (7.37)
0.299 (7.60)
0.003 (0.10)
0.012 (0.30)
0.050" Typical
0.393 (10.00)
0.420 (10.65)
0.092 (2.35)
0.105 (2.65)
0.050"
Typical
0.030" Typical
FOOTPRINT
20 Places
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
3926 FHD F23
11
Page 12
X22C12
ORDERING INFORMATION
X22C12XX
Device
Store Cycles
Blank = 1,000,000
Temperature Range
Blank = Commercial = 0°C to +70°C
I = Industrial = –40°C to +85°C
M = Military = –55°C to +125°C
MB = MIL-STD-883
Package
P = 18-Lead Plastic DIP
D = 18-Lead Cerdip
S = 20-Lead Plastic SOIC (300 mil)
LIMITED WARRANTY
Devices sold by Xicor, Inc. are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. Xicor, Inc. makes no warranty,
express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement.
Xicor, Inc. makes no warranty of merchantability or fitness for any purpose. Xicor, Inc. reserves the right to discontinue production and change specifications and
prices at any time and without notice.
Xicor, Inc. assumes no responsibility for the use of any circuitry other than circuitry embodied in a Xicor, Inc. product. No other circuits, patents, licenses are
implied.
U.S. PATENTS
Xicor products are covered by one or more of the following U.S. Patents: 4,263,664; 4,274,012; 4,300,212; 4,314,265; 4,326,134; 4,393,481; 4,404,475;
4,450,402; 4,486,769; 4,488,060; 4,520,461; 4,533,846; 4,599,706; 4,617,652; 4,668,932; 4,752,912; 4,829, 482; 4,874, 967; 4,883, 976. Foreign patents and
additional patents pending.
LIFE RELATED POLICY
In situations where semiconductor component failure may endanger life, system designers using this product should design the system with appropriate error
detection and correction, redundancy and back-up features to prevent such an occurence.
Xicor’s products are not authorized for use in critical components in life support devices or systems.
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose
failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant
injury to the user.
2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life
support device or system, or to affect its safety or effectiveness.
12
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