This X24C01 device has been acquired by
IC Microsystems from Xicor, Inc.
ICmic
IC MICROSYSTEMS
TM
1K
X24C01
Serial E PROM
2
128 x 8 Bit
FEATURES
DESCRIPTION
The X24C01 is a CMOS 1024 bit serial E PROM,
internally organized as 128 x 8. The X24C01 features a
serial interface and software protocol allowing operation
on a simple two wire bus.
2
•
2.7V to 5.5V Power Supply
•
Low Power CMOS
—Active Current Less Than 1 mA
—Standby Current Less Than 50 µA
•
Internally Organized 128 x 8
•
2 Wire Serial Interface
•
Four Byte Page Write Mode
•
Self Timed Write Cycle
—Bidirectional Data Transfer Protocol
Xicor E PROMs are designed and tested for applica-
tions requiring extended endurance. Inherent data
2
retention is greater than 100 years.
—Typical Write Cycle Time of 5 ms
•
High Reliability
—Endurance: 100,000 Cycles
—Data Retention: 100 Years
•
8-Pin Mini-DIP, 8-PIN MSOP, and 8-PIN SOIC
Packages
FUNCTIONAL DIAGRAM
(8) V CC
(4) V SS
START CYCLE
H.V. GENERATION
TIMING
& CONTROL
(5) SDA
START
STOP
LOGIC
CONTROL
LOGIC
XDEC
E PROM
32 X 32
2
(6) SCL
LOAD
INC
WORD
ADDRESS
COUNTER
R/W
YDEC
8
CK
PIN
DATA REGISTER
D
OUT
D
OUT
ACK
3837 FHD F01
© Xicor, 1991 Patents Pending
3837-1.2 7/28/97 T1/C0/D0 SH
1
Characteristics subject to change without notice
X24C01
PIN DESCRIPTIONS
Serial Clock (SCL)
The SCL input is used to clock all data into and out of
the device.
Serial Data (SDA)
SDA is a bidirectional pin used to transfer data into and
out of the device. It is an open drain output and may be
wire-ORed with any number of open drain or open
collector outputs.
An open drain output requires the use of a pull-up
resistor. For selecting typical values, refer to the Guide-
lines for Calculating Typical Values of Bus Pull-Up
Resistors graph.
SOIC/MSOP
1
2
3
4
X24C01
8
7
6
5
V
CC
NC
PIN CONFIGURATION
DIP
PLASTIC
1
2
3
4
X24C01
8
7
6
5
NC
NC
V
CC
NC
NC
V
SS
SCL
SDA
3837 FHD F02
PIN NAMES
Symbol
NC
V
SS
V
CC
SDA
SCL
A.C. CONDITIONS OF TEST
Input Pulse Levels
Input Rise and
Fall Times
Input and Output
Timing Levels
NC
NC
Description
No Connect
Ground
Supply Voltage
Serial Data
Serial Clock
3837 PGM T01
NC
V
SS
SCL
SDA
3837 FHD F03
EQUIVALENT A.C. LOAD CIRCUIT
5V
2190Ο
V
CC
x 0.1 to V
CC
x 0.9
10 ns
OUTPUT
V
CC
x 0.5
3837 PGM T02
100pF
3837 FHD F16
2
X24C01
DEVICE OPERATION
The X24C01 supports a bidirectional bus oriented pro-
tocol. The protocol defines any device that sends data
onto the bus as a transmitter and the receiving device as
the receiver. The device controlling the transfer is a
master and the device being controlled is the slave. The
master will always initiate data transfers and provide the
Clock and Data Conventions
Data states on the SDA line can change only during SCL
LOW. SDA state changes during SCL HIGH are re-
served for indicating start and stop conditions. Refer to
Figures 1 and 2.
Start Condition
All commands are preceded by the start condition,
which is a HIGH to LOW transition of SDA when SCL is
HIGH. The X24C01 continuously monitors the SDA and
SCL lines for the start condition and will not respond to
clock for both transmit and receive operations. There-
fore, the X24C01 will be considered a slave in all
applications.
any command until this condition has been met.
Figure 1. Data Validity
SCL
SDA
DATA STABLE
DATA
CHANGE
3837 FHD F06
3
X24C01
The X24C01 will respond with an acknowledge after
recognition of a start condition, a seven bit word address
and a R/W bit. If a write operation has been selected, the
X24C01 will respond with an acknowledge after each
Stop Condition
All communications must be terminated by a stop con-
dition, which is a LOW to HIGH transition of SDA when
SCL is HIGH. The stop condition is also used by the
X24C01 to place the device in the standby power mode
after a read sequence. A stop condition can only be
issued after the transmitting device has released the bus.
Acknowledge
Acknowledge is a software convention used to indicate
successful data transfers. The transmitting device will
release the bus after transmitting eight bits. During the ninth
clock cycle the receiver will pull the SDA line LOW
byte of data is received.
In the read mode the X24C01 will transmit eight bits of data,
release the SDA line and monitor the line for an
acknowledge. If an acknowledge is detected and no
stop condition is generated by the master, the X24C01
will continue to transmit data. If an acknowledge is not
detected, the X24C01 will terminate further data trans-
missions. The master must then issue a stop condition to
return the X24C01 to the standby power mode and
to acknowledge that it received the eight bits of data.
Refer to Figure 3.
place the device into a known state.
Figure 2. Definition of Start and Stop
SCL
SDA
START CONDITION
STOP CONDITION
3837 FHD F07
Figure 3. Acknowledge Response From Receiver
SCL FROM
MASTER
1
8
9
DATA
OUTPUT
FROM
TRANSMITTER
DATA
OUTPUT
FROM
RECEIVER
START
ACKNOWLEDGE
3837 FHD F08
4
X24C01
WRITE OPERATIONS
Byte Write
To initiate a write operation, the master sends a start
condition followed by a seven bit word address and a write
bit. The X24C01 responds with an acknowledge, then waits
for eight bits of data and then responds with an
acknowledge. The master then terminates the transfer by
generating a stop condition, at which time the X24C01
begins the internal write cycle to the nonvolatile memory.
While the internal write cycle is in progress, the X24C01
inputs are disabled, and the device will not respond to any
requests from the master. Refer to Figure 4 for the
address, acknowledge and data transfer sequence.
Page Write
The most significant five bits of the word address define
the page address. The X24C01 is capable of a four byte page
write operation. It is initiated in the same manner as
the byte write operation, but instead of terminating the
transfer of data after the first data byte, the master can
transmit up to three more bytes. After the receipt of each data
byte, the X24C01 will respond with an acknowledge.
After the receipt of each data byte, the two low order address
bits are internally incremented by one. The high
order five bits of the address remain constant. If the
master should transmit more than four data bytes prior
to generating the stop condition, the address counter will “roll
over” and the previously transmitted data will be
overwritten. As with the byte write operation, all inputs are
disabled until completion of the internal write cycle.
Refer to Figure 5 for the address, acknowledge and data
transfer sequence.
Figure 4. Byte Write
S
T
BUS ACTIVITY:
WORD
A ADDRESS (n)
R
T
S
M
S
DATA n
S
T
O
P
SDA LINE
BUS ACTIVITY:
X24C01
P
L
R
A
S
/
C
K
B
B
W
A
C
K
3837 FHD F09
Figure 5. Page Write
S
T
BUS ACTIVITY:
A
R
WORD
ADDRESS (n)
DATA n
DATA n+1
DATA n+3
S
T
O
P
T
SDA LINE
BUS ACTIVITY:
X24C01
S
M
S
P
L
R
A
S
/
C
K
B
A
C
A
C
A
C
B
W
K
K
K
3837 FHD F10
5
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