Features
•
Write Protect Pin for Hardware Data Protection
•
– Utilizes Different Array Protection Compared to the AT24C02/04/08
Low Voltage and Standard Voltage Operation
– 5.0 (V
CC
= 4.5V to 5.5V)
– 2.7 (V
CC
= 2.7V to 5.5V)
– 2.5 (V
CC
= 2.5V to 5.5V)
– 1.8 (V
CC
= 1.8V to 5.5V)
Internally Organized 256 x 8 (2K), 512 x 8 (4K) or 1024 x 8 (8K)
2-Wire Serial Interface
Schmitt Trigger, Filtered Inputs for Noise Supperssion
Bidirectional Data Transfer Protocol
100 kHz (1.8V, 2.5V, 2.7V) and 400 kHz (5V) Compatibility
8-Byte Page (2K), 16-Byte Page (4K, 8K) Write Modes
Partial Page Writes Are Allowed
Self-Timed Write Cycle (10 ms max)
High Reliability
– Endurance: 1 Million Write Cycles
– Data Retention: 100 Years
– ESD Protection: >3000V
Automotive Grade and Extended Temperature Devices Available
8-Pin and 14-Pin JEDEC SOIC, 8-Pin PDIP, and 8-Pin TSSOP Packages
•
•
•
•
•
•
•
•
•
2-Wire Serial
EEPROM
2K (256 x 8)
4K (512 x 8)
8K (1024 x 8)
•
•
Description
The AT24C02A/04A/08A provides 2048/4096/8192 bits of serial electrically erasable
and programmable read only memory (EEPROM) organized as 256/512/1024 words
of 8 bits each. The device is optimized for use in many industrial and commercial
applications where low power and low voltage operation are essential. The
AT24C02A/04A/08A is available in space saving 8-pin PDIP, 8-pin and 14-pin JEDEC
SOIC, and 8-pin TSSOP packages and is accessed via a 2-wire serial interface. In
addition, the entire family is available in 5.0V (4.5V to 5.5V), 2.7V (2.7V to 5.5V), 2.5V
(2.5V to 5.5V) and 1.8V (1.8V to 5.5V) versions.
AT24C02A
AT24C04A
AT24C08A
Pin Configurations
Pin Name
A0 - A2
SDA
SCL
WP
NC
Function
Address Inputs
Serial Data
Serial Clock Input
Write Protect
No Connect
A0
A1
A2
GND
NC
VCC
WP
NC
SCL
SDA
NC
A0
A1
A2
GND
8-Pin PDIP
1
2
3
4
8
7
6
5
VCC
WP
SCL
SDA
AT24C02A/04A/
08A
8-Pin SOIC
1
2
3
4
8
7
6
5
VCC
WP
SCL
SDA
14-Pin SOIC
NC
A0
A1
NC
A2
GND
NC
1
2
3
4
5
6
7
14
13
12
11
10
9
8
8-Pin TSSOP
A0
A1
A2
GND
1
2
3
4
8
7
6
5
VCC
WP
SCL
SDA
Rev. 0976B–07/98
1
Absolute Maximum Ratings*
Operating Temperature .................................. -55°C to +125°C
Storage Temperature ..................................... -65°C to +150°C
Voltage on Any Pin
with Respect to Ground .....................................-1.0V to +7.0V
Maximum Operating Voltage........................................... 6.25V
DC Output Current........................................................ 5.0 mA
*NOTICE:
Stresses beyond those listed under “Absolute
Maximum Ratings” may cause permanent dam-
age to the device. This is a stress rating only and
functional operation of the device at these or any
other conditions beyond 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.
Block Diagram
Pin Description
SERIAL CLOCK (SCL):
The SCL input is used to positive
edge clock data into each EEPROM device and negative
edge clock data out of each device.
SERIAL DATA (SDA):
The SDA pin is bidirectional for
serial data transfer. This pin is open-drain driven and may
be wire-ORed with any number of other open-drain or open
collector devices.
DEVICE/PAGE ADDRESSES (A2, A1, A0):
The A2, A1
and A0 pins are device address inputs that are hard wired
for the AT24C02A. As many as eight 2K devices may be
addressed on a single bus system (device addressing is
discussed in detail under the Device Addressing section).
The AT24C04A uses the A2 and A1 inputs for hard wire
addressing and a total of four 4K devices may be
addressed on a single bus system. The A0 pin is a no con-
nect.
The AT24C08A only uses the A2 input for hardwire
addr es si ng a nd a total of two 8K de vi ces ma y be
addressed on a single bus system. The A0 and A1 pins are
no connects.
WRITE PROTECT (WP):
The AT24C02A/04A/08A has a
Write Protect pin that provides hardware data protection.
The Write Protect pin allows normal read/write operations
when connected to ground (GND). When the Write Protect
2
AT24C02A/04A/08A
AT24C02A/04A/08A
pin is connected to V
CC
, the write protection feature is
enabled and operates as shown in the following table.
Memory Organization
AT24C02A, 2K SERIAL EEPROM:
Internally organized
with 256 pages of 1-byte each, the 2K requires an 8 bit
data word address for random word addressing.
AT24C04A, 4K SERIAL EEPROM:
The 4K is internally
organized with 256 pages of 2-bytes each. Random word
addressing requires a 9 bit data word address.
AT24C08A, 8K SERIAL EEPROM:
The 8K is internally
organized with 4 blocks of 256 pages of 4-bytes each.
Random word addressing requires a 10 bit data word
address.
WP Pin
Status
At V
CC
At GND
Part of the Array Protected
24C02A
Upper Half
(1K) Array
24C04A
Upper Half
(2K) Array
24C08A
Full (8K)
Array
Normal Read/Write Operations
Pin Capacitance
Applicable over recommended operating range from T
A
= 25°C, f = 1.0 MHz, V
CC
= +1.8V.
Symbol
C
I/O
C
IN
Note:
Test Condition
Input/Output Capacitance (SDA)
Input Capacitance (A
0
, A
1
, A
2
, SCL)
1. This parameter is characterized and is not 100% tested.
Max
8
6
Units
pF
pF
Conditions
V
I/O
= 0V
V
IN
= 0V
DC Characteristics
Applicable over recommended operating range from: T
AI
= -40°C to +85°C, V
CC
= +1.8V to +5.5V, T
AC
= 0°C to +70°C,
V
CC
= +1.8V to +5.5V (unless otherwise noted).
Symbol
V
CC1
V
CC2
V
CC3
V
CC4
I
CC
I
CC
I
SB1
I
SB2
I
SB3
I
SB4
I
LI
I
LO
V
IL
V
IH
V
OL2
V
OL1
Note:
Parameter
Supply Voltage
Supply Voltage
Supply Voltage
Supply Voltage
Supply Current V
CC
= 5.0V
Supply Current V
CC
= 5.0V
Standby Current V
CC
= 1.8V
Standby Current V
CC
= 2.5V
Standby Current V
CC
= 2.7V
Standby Current V
CC
= 5.0V
Input Leakage Current
Output Leakage Current
Input Low Level
(1)
Input High Level
(1)
Output Low Level V
CC
= 3.0V
Output Low Level V
CC
= 1.8V
I
OL
= 2.1 mA
I
OL
= 0.15 mA
READ at 100 kHz
WRITE at 100 kHz
V
IN
= V
CC
or V
SS
V
IN
= V
CC
or V
SS
V
IN
= V
CC
or V
SS
V
IN
= V
CC
or V
SS
V
IN
= V
CC
or V
SS
V
OUT
= V
CC
or V
SS
-0.6
V
CC
x 0.7
Test Condition
Min
1.8
2.5
2.7
4.5
0.4
2.0
0.6
1.4
1.6
8.0
0.10
0.05
Typ
Max
5.5
5.5
5.5
5.5
1.0
3.0
3.0
4.0
4.0
18.0
3.0
3.0
V
CC
x 0.3
V
CC
+ 0.5
0.4
0.2
Units
V
V
V
V
mA
mA
µA
µA
µA
µA
µA
µA
V
V
V
V
1. V
IL
min and V
IH
max are reference only and are not tested.
3
AC Characteristics
Applicable over recommended operating range from T
A
= -40°C to +85°C, V
CC
= +1.8V to +5.5V, CL = 1 TTL Gate and
100 pF (unless otherwise noted).
2.7-, 2.5-, 1.8-volt
Symbol
f
SCL
t
LOW
t
HIGH
t
I
t
AA
t
BUF
t
HD.STA
t
SU.STA
t
HD.DAT
t
SU.DAT
t
R
t
F
t
SU.STO
t
DH
t
WR
Endurance
(1)
Note:
Parameter
Clock Frequency, SCL
Clock Pulse Width Low
Clock Pulse Width High
Noise Suppression Time
(1)
Clock Low to Data Out Valid
Time the bus must be free before
a new transmission can start
(1)
Start Hold Time
Start Set-up Time
Data In Hold Time
Data In Set-up Time
Inputs Rise Time
(1)
Inputs Fall Time
(1)
Stop Set-up Time
Data Out Hold Time
Write Cycle Time
5.0V, 25°C, Page Mode
1M
4.7
100
10
1M
0.1
4.7
4.0
4.7
0
200
1.0
300
0.6
50
10
4.7
4.0
100
4.5
0.1
1.2
0.6
0.6
0
100
0.3
300
Min
Max
100
1.2
0.6
50
0.9
5.0-volt
Min
Max
400
Units
kHz
µs
µs
ns
µs
µs
µs
µs
µs
ns
µs
ns
µs
ns
ms
Write
Cycles
1. This parameter is characterized and is not 100% tested.
Device Operation
CLOCK and DATA TRANSITIONS:
The SDA pin is nor-
mally pulled high with an external device. Data on the SDA
pin may change only during SCL low time periods (refer to
Data Validity timing diagram). Data changes during SCL
high periods will indicate a start or stop condition as
defined below.
START CONDITION:
A high-to-low transition of SDA with
SCL high is a start condition which must precede any other
command (refer to Start and Stop Definition timing dia-
gram).
STOP CONDITION:
A low-to-high transition of SDA with
SCL high is a stop condition. After a read sequence, the
stop command will place the EEPROM in a standby power
mode (refer to Start and Stop Definition timing diagram).
ACKNOWLEDGE:
All addresses and data words are seri-
ally transmitted to and from the EEPROM in 8 bit words
.
The EEPROM sends a zero to acknowledge that it has
received each word. This happens during the ninth clock
cycle.
STANDBY MODE:
The AT24C02A/04A/08A features a low
power standby mode which is enabled: (a) upon power-up
and (b) after the receipt of the STOP bit and the completion
of any internal operations.
MEMORY RESET:
After an interruption in protocol, power
loss or system reset, any 2-wire part can be reset by follow-
ing these steps:(a) Clock up to 9 cycles, (b) look for SDA
high in each cycle while SCL is high and then (c) create a
start condition as SDA is high.
4
AT24C02A/04A/08A
AT24C02A/04A/08A
Bus Timing (SCL: Serial Clock, SDA: Serial Data I/O)
Write Cycle Timing (SCL: Serial Clock, SDA: Serial Data I/O)
SCL
SDA
8th BIT
WORD n
ACK
t
WR(1)
STOP
CONDITION
START
CONDITION
Note:
1.
The write cycle time t
WR
is the time from a valid stop condition of a write sequence to the end of the interval
clear/write cycle.
5
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