S524A40X10/40X20/40X40
1K/2K/4K-bit
Serial EEPROM for Low Power
Data Sheet
2-1
OVERVIEW
The S524A40X10/40X20/40X40 serial EEPROM has a 1,024/2,048/4,096-bit (128/256/512-byte) capacity,
supporting the standard I2C™-bus serial interface. It is fabricated using Samsung’s most advanced CMOS
technology. It has been developed for low power and low voltage applications (1.8 V to 5.5 V). Important features
are a hardware-based write protection circuit for the entire memory area and software-based write protection logic
for the lower 128 bytes. Hardware-based write protection is controlled by the state of the write-protect (WP) pin.
The software-based method is one-time programmable and permanent. Using one-page write mode, you can
load up to 16 bytes of data into the EEPROM in a single write operation. Another significant feature of the
S524A40X10/40X20/40X40 is its support for fast mode and standard mode.
FEATURES
I2C-Bus Interface
•Two-wire serial interface
•Automatic word address increment
EEPROM
•1K/2K/4K-bit (128/256/512-byte) storage area
•16-byte page buffer
•Hardware-based write protection for the entire
EEPROM (using the WP pin)
•Software-based write protection for the lower
128-byte EEPROM
•EEPROM programming voltage generated
on chip
•1,000,000 erase/write cycles
•100 years data retention
Operating Characteristics
•Operating voltage
—1.8 V to 5.5 V
•Operating current
—Maximum write current: < 3 mA at 5.5 V
—Maximum read current: < 200 µA at 5.5 V
—Maximum stand-by current: < 5 µA at 5.5 V
•Operating temperature range
—– 25°C to + 70°C (commercial)
—– 40°C to + 85°C (industrial)
•Operating clock frequencies
—100 kHz at standard mode
—400 kHz at fast mode
•Electrostatic discharge (ESD)
—5,000 V (HBM)
—500 V (MM)
Packages
•8-pin DIP, SOP, and TSSOP
S524A40X10/40X20/40X40 SERIAL EEPROM DATA SHEET
2-2
Start/Stop
Logic
Slave Address
Comparator Word Address
Pointer Row
decoder
EEPROM
Cell Array
128 x 8 bits
256 x 8 bits
512 x 8 bits
HV Generation
Timing Control
Control Logic
Column Decoder
Data Register
DOUT and ACK
SCL
WP
SDA
A0
A1
A2
Figure 2-1. S524A40X10/40X20/40X40 Block Diagram
DATA SHEET S524A40X10/40X20/40X40 SERIAL EEPROM
2-3
S524A40X10/
40X20/40X40
VCC WP SCL SDA
A0 A1 A2 VSS
NOTE: The S524A40X10/40X20/40X40 is available
in 8-pin DIP, SOP, and TSSOP package.
Figure 2-2. Pin Assignment Diagram
Table 2-1. S524A40X10/40X20/40X40 Pin Descriptions
Name Type Description Circuit
Type
A0, A1, A2 Input Input pins for device address selection. To configure a device address,
these pins should be connected to the VCC or VSS of the device.
These pins are internally pulled down to VSS.
1
VSS –Ground pin. –
SDA I/O Bi-directional data pin for the I2C-bus serial data interface. Schmitt
trigger input and open-drain output. An external pull-up resistor must
be connected to VCC. Typical values for this pull-up resistor are 4.7 kΩ
(100 kHz) and 1 kΩ (400 kHz).
3
SCL Input Schmitt trigger input pin for serial clock input. 2
WP Input Input pin for hardware write protection control. If you tie this pin to VCC,
the write function is disabled to protect previously written data in the
entire memory; if you tie it to VSS, the write function is enabled.
This pin is internally pulled down to VSS.
1
VCC –Single power supply. –
NOTE:See the following page for diagrams of pin circuit types 1, 2, and 3.
S524A40X10/40X20/40X40 SERIAL EEPROM DATA SHEET
2-4
A0, A1,
A2, WP
Figure 2-3. Pin Circuit Type 1
SCL Noise
Filter
Figure 2-4. Pin Circuit Type 2
SDA
VSS
Data Out
Noise
Filter Data In
Figure 2-5. Pin Circuit Type 3
DATA SHEET S524A40X10/40X20/40X40 SERIAL EEPROM
2-5
FUNCTION DESCRIPTION
I2C-BUS INTERFACE
The S524A40X10/40X20/40X40 supports the I2C-bus serial interface data transmission protocol. The two-wire bus
consists of a serial data line (SDA) and a serial clock line (SCL). The SDA and the SCL lines must be connected
to VCC by a pull-up resistor that is located somewhere on the bus.
Any device that puts data onto the bus is defined as the “transmitter” and any device that gets data from the bus
is the “receiver.” The bus is controlled by a master device which generates the serial clock and start/stop
conditions, controlling bus access. Using the A0,A1 and A2 input pins, up to eight S524A40X10/40X20 (four for
S524A40X40) devices can be connected to the same I2C-bus as slaves (see Figure 2-6). Both the master and
slaves can operate as transmitter or receiver, but the master device determines which bus operating mode would
be active.
SDA
Bus Master
(Transmitter/
Receiver)
MCU
S524A40X20
Tx/Rx
A0 A1 A2
Slave 1
To V
CC
or V
SS
S524A40X20
Tx/Rx
A0 A1 A2
Slave 2
To V
CC
or V
SS
S524A40X20
Tx/Rx
A0 A1 A2
Slave 3
To V
CC
or V
SS
S524A40X20
Tx/Rx
A0 A1 A2
Slave 8
To V
CC
or V
SS
V
CC
V
CC
SCL
NOTE: The A0 does not affect the device address of the S524A40X40.
Figure 2-6. Typical Configuration (16 Kbits of Memory on the I2C-Bus)
S524A40X10/40X20/40X40 SERIAL EEPROM DATA SHEET
2-6
I2C-BUS PROTOCOLS
Here are several rules for I2C-bus transfers:
—A new data transfer can be initiated only when the bus is currently not busy.
—MSB is always transferred first in transmitting data.
—During a data transfer, the data line (SDA) must remain stable whenever the clock line (SCL) is High.
The I2C-bus interface supports the following communication protocols:
•Bus not busy: The SDA and the SCL lines remain High level when the bus is not active.
•Start condition: Start condition is initiated by a High-to-Low transition of the SDA line while SCL remains High
level. All bus commands must be preceded by a start condition.
•Stop condition: A stop condition is initiated by a Low-to-High transition of the SDA line while SCL remains
High level. All bus operations must be completed by a stop condition (see Figure 2-7).
SCL
SDA
Start
Condition Data or
ACK Valid Data
Change
~
~~
~
Stop
Condition
Figure 2-7. Data Transmission Sequence
•Data valid: Following a start condition, the data becomes valid if the data line remains stable for the duration
of the High period of SCL. New data must be put onto the bus while SCL is Low. Bus timing is one clock
pulse per data bit. The number of data bytes to be transferred is determined by the master device. The total
number of bytes that can be transferred in one operation is theoretically unlimited.
•ACK (Acknowledge): An ACK signal indicates that a data transfer is completed successfully. The transmitter
(the master or the slave) releases the bus after transmitting eight bits. During the 9th clock, which the master
generates, the receiver pulls the SDA line low to acknowledge that it successfully received the eight bits of
data (see Figure 2-8). But the slave does not send an ACK if an internal write cycle is still in progress.
In data read operations, the slave releases the SDA line after transmitting 8 bits of data and then monitors
the line for an ACK signal during the 9th clock period. If an ACK is detected, the slave will continue to
transmit data. If an ACK is not detected, the slave terminates data transmission and waits for a stop condition
to be issued by the master before returning to its stand-by mode.
DATA SHEET S524A40X10/40X20/40X40 SERIAL EEPROM
2-7
Master
SCL Line
Data from
Transmitter
ACK
ACK from
Receiver
Bit 9Bit 1
Figure 2-8. Acknowledge Response From Receiver
•Slave Address: After the master initiates a Start condition, it must output the address of the device to be
accessed. The most significant four bits of the slave address are called the “device identifier”. The identifier
for the S524A40X10/40X20/40X40 is “1010B”. The next three bits comprise the address of a specific device.
The device address is defined by the state of the A0, A1 and A2 pins. Using this addressing scheme, you can
cascade up to eight S524A40X10/40X20 or four S524A40X40 on the bus (see Table 2-2 below). The b1 for
S524A40X40 is used by the master to select which of the blocks of internal memory (1 block = 256 words)
are to be accessed. The bit is in effect the most significant bit of the word address.
•Read/Write: The final (eighth) bit of the slave address defines the type of operation to be performed. If the
R/W bit is “1”, a read operation is executed. If it is “0”, a write operation is executed.
Table 2-2. Slave Device Addressing
Function Device Identifier Device Address R/WW Bit
b7 b6 b5 b4 b3 b2 b1(note) b0
Read 1010 A2 A1 A0 1
Write 1010 A2 A1 A0 0
Write-protect 0110 A2 A1 A0 0
NOTE: The b1 for S524A40X40 corresponds to the MSB of the memory array address word.
S524A40X10/40X20/40X40 SERIAL EEPROM DATA SHEET
2-8
BYTE WRITE OPERATION
In a complete byte write operation, the master transmits the slave address, word address, and one data byte to
the S524A40X10/40X20/40X40 slave device (see Figure 2-9).
Slave AddressStart Word Address Data Stop
A
C
K
A
C
K
A
C
K
Figure 2-9. Byte Write Operation
Following the Start condition, the master sends the device identifier (4 bits), the device address (3 bits), and an
R/W bit set to “0” onto the bus. Then the addressed S524A40X10/40X20/40X40 generates an ACK and waits for
the next byte. The next byte to be transmitted by the master is the word address. This 8-bit address is written into
the word address pointer of the S524A40X10/40X20/40X40.
When the S524A40X10/40X20/40X40 receives the word address, it responds by issuing an ACK and then waits
for the next 8-bit data. When it receives the data byte, the S524A40X10/40X20/40X40 again responds with an
ACK. The master terminates the transfer by generating a Stop condition, at which time the
S524A40X10/40X20/40X40 begins the internal write cycle.
While the internal write cycle is in progress, all S524A40X10/40X20/40X40 inputs are disabled and the
S524A40X10/40X20/40X40 does not respond to additional requests from the master.
DATA SHEET S524A40X10/40X20/40X40 SERIAL EEPROM
2-9
PAGE WRITE OPERATION
The S524A40X10/40X20/40X40 can also perform 16-byte page write operation. A page write operation is initiated
in the same way as a byte write operation. However, instead of finishing the write operation after the first data
byte is transferred, the master can transmit up to 15 additional bytes. The S524A40X10/40X20/40X40 responds
with an ACK each time it receives a complete byte of data (see Figure 2-10).
Slave Address Word Address (n)Start
A
C
K
A
C
K
Data (n)
A
C
K
A
C
K
Data (≤ n + 15) Stop
A
C
K
Figure 2-10. Page Write Operation
The S524A40X10/40X20/40X40 automatically increments the word address pointer each time it receives a
complete data byte. When one byte has been received, the internal word address pointer increments to the next
address and the next data byte can be received.
If the master transmits more than 16 bytes before it generates a stop condition to end the page write operation,
the S524A40X10/40X20/40X40 word address pointer value “rolls over” and the previously received data is
overwritten. If the master transmits less than 16 bytes and generates a stop condition, the
S524A40X10/40X20/40X40 writes the received data to the corresponding EEPROM address.
During a page write operation, all inputs are disabled and there is no response to additional requests from the
master until the internal write cycle is completed.
S524A40X10/40X20/40X40 SERIAL EEPROM DATA SHEET
2-10
POLLING FOR AN ACK SIGNAL
When the master issues a stop condition to initiate a write cycle, the S524A40X10/40X20/40X40 starts an internal
write cycle. The master can then immediately begin polling for an ACK from the slave device.
To poll for an ACK signal in a write operation, the master issues a start condition followed by the slave address.
As long as the S524A40X10/40X20/40X40 remains busy with the write operation, no ACK is returned. When the
S524A40X10/40X20/40X40 completes the write operation, it returns an ACK and the master can then proceed
with the next read or write operation (see Figure 2-11).
Send Write
Command
Send Stop Condition to
Initiate Write Cycle
Send Start
Condition
Send Slave Address
with R/W bit = "0"
Start Next
Operation
ACK = "0" ?
Yes
No
Figure 2-11. Master Polling for an ACK Signal from a Slave Device
DATA SHEET S524A40X10/40X20/40X40 SERIAL EEPROM
2-11
SOFTWARE-BASED WRITE PROTECTION
You can write-protect the lower 128 bytes of the EEPROM, locations 00H–7FH, in one operation. To do this, you
simply write a value to a one-time, write-only register. Once you have applied this write protection, any write
attempt to access the lower 128-byte area is ignored. In other words, the write protection is permanent. The effect
of such a failed attempt is processed in the same way as an invalid I2C-bus protocol.
To enable write protection, you must execute a write operation to the write protection register. To access the write
protection register, you use the device address “0110”. The word address and data in this write operation can be
any value and the timing and wave form characteristics are identical to a normal byte write operation (see Figure
2-12).
Slave AddressStart Word Address
(Ignored) Stop
A
C
K
A
C
K
A
C
K
Data
(Ignored)
Figure 2-12. Write Protection Operation
HARDWARE-BASED WRITE PROTECTION
You can also write-protect the entire memory area of the S524A40X10/40X20/40X40. This method of write
protection is controlled by the state of the Write Protect (WP) pin.
When the WP pin is connected to VCC, any attempt to write a value to the memory is ignored.
The S524A40X10/40X20/40X40 will acknowledge slave and word address, but it will not generate an
acknowledge after receiving the first byte of the data. Thus the write cycle will not be started when the stop
condition is generated. By connecting the WP pin to VSS, the write function is allowed for the entire memory.
These write protection features effectively change the EEPROM to a ROM in order to prevent data from being
overwritten. Whenever the write function is disabled, a slave address and a word address are acknowledged on
the bus, but data bytes are not acknowledged.
S524A40X10/40X20/40X40 SERIAL EEPROM DATA SHEET
2-12
CURRENT ADDRESS BYTE READ OPERATION
The internal word address pointer maintains the address of the last word accessed, incremented by one.
Therefore, if the last access (either read or write) was to the address “n”, the next read operation would access
data at address “n+1”.
When the S524A40X10/40X20/40X40 receives a slave address with the R/W bit set to “1”, it issues an ACK and
sends the eight bits of data. The master does not acknowledge the transfer but it does generate a Stop condition.
In this way, the S524A40X10/40X20/40X40 effectively stops the transmission (see Figure 2-13).
Slave Address DataStart
A
C
K
Stop
N
O
A
C
K
Figure 2-13. Current Address Byte Read Operation
DATA SHEET S524A40X10/40X20/40X40 SERIAL EEPROM
2-13
RANDOM ADDRESS BYTE READ OPERATION
Using random read operations, the master can access any memory location at any time. Before it issues the
slave address with the R/W bit set to “1”, the master must first perform a “dummy” write operation. This operation
is performed in the following steps:
1. The master first issues a Start condition, the slave address, and the word address to be read. (This step sets
the internal word address pointer of the S524A40X10/40X20/40X40 to the desired address.)
2. When the master receives an ACK for the word address, it immediately re-issues a start condition followed
by another slave address, with the R/W bit set to “1”.
3. The S524A40X10/40X20/40X40 then sends an ACK and the 8-bit data stored at the desired address.
4. At this point, the master does not acknowledge the transmission, but generates a stop condition instead.
5. In response, the S524A40X10/40X20/40X40 stops transmitting data and reverts to its stand-by mode (see
Figure 2-14).
Slave Address Word AddressStart
A
C
K
A
C
K
Slave Address
A
C
K
N
O
A
C
K
StopStart Data (n)
Figure 2-14. Random Address Byte Read Operation
S524A40X10/40X20/40X40 SERIAL EEPROM DATA SHEET
2-14
SEQUENTIAL READ OPERATION
Sequential read operations can be performed in two ways: as a series of current address reads or as random
address reads. The first data is sent in the same way as the previous read mode used on the bus. The next time,
however, the master responds with an ACK, indicating that it requires additional data.
The S524A40X10/40X20/40X40 continues to output data for each ACK it receives. To stop the sequential read
operation, the master does not respond with an ACK, but instead issues a Stop condition.
Using this method, data is output sequentially with the data from address “n” followed by the data from “n+1”. The
word address pointer for read operations increments all word addresses, allowing the entire EEPROM to be read
sequentially in a single operation. After the entire EEPROM is read, the word address pointer “rolls over” and the
S524A40X10/40X20/40X40 continues to transmit data for each ACK it receives from the master (see Figure 2-
15).
Slave Address Data (n)Start
A
C
K
A
C
K
N
O
A
C
K
Data (n + x)
A
C
K
~
~
Figure 2-15. Sequential Read Operation
DATA SHEET S524A40X10/40X20/40X40 SERIAL EEPROM
2-15
ELECTRICAL DATA
Table 2-3. Absolute Maximum Ratings
(TA = 25°C)
Parameter Symbol Conditions Rating Unit
Supply voltage VCC –– 0.3 to + 7.0 V
Input voltage VIN –– 0.3 to + 7.0 V
Output voltage VO–– 0.3 to + 7.0 V
Operating temperature TA–– 40 to + 85 °C
Storage temperature TSTG –– 65 to + 150 °C
Electrostatic discharge VESD HBM 5000 V
MM 500
Table 2-4. D.C. Electrical Characteristics
(TA = – 25°C to + 70°C (C), – 40°C to + 85°C (I), VCC = 1.8 V to 5.5 V)
Parameter Symbol Conditions Min Typ Max Unit
Input low voltage VIL SCL, SDA, A0, A1, A2 – – 0.3 VCC V
Input high voltage VIH 0.7 VCC – – V
Input leakage current ILI VIN = 0 to VCC – – 10 µA
Output leakage current ILO VO = 0 to VCC – – 10 µA
Output low voltage VOL IOL = 0.15 mA, VCC = 1.8 V – – 0.2 V
IOL = 2.1 mA, VCC = 2.5 V – – 0.4
Supply current Write ICC1 VCC = 5.5 V, 400 kHz ––3mA
ICC2 VCC = 1.8 V, 100 kHz ––1
Read ICC3 VCC = 5.5 V, 400 kHz – – 0.2
ICC4 VCC = 1.8 V, 100 kHz – – 60 µA
Stand-by current ICC5 VCC = SDA = SCL = 5.5 V,
all other inputs = 0 V ––5µA
ICC6 VCC = SDA = SCL = 1.8 V,
all other inputs = 0 V ––1
S524A40X10/40X20/40X40 SERIAL EEPROM DATA SHEET
2-16
Table 2-4. D.C. Electrical Characteristics (Continued)
(TA = – 25°C to + 70°C (C), – 40°C to + 85°C (I), VCC = 1.8 V to 5.5 V)
Parameter Symbol Conditions Min Typ Max Unit
Input capacitance CIN 25°C, 1MHz,
VCC = 5 V, VIN = 0 V,
A0, A1, A2, SCL and WP pin
– – 10 pF
Input/output capacitance CI/O 25°C, 1MHz,
VCC = 5 V, VI/O = 0 V,
SDA pin
– – 10
Table 2-5. A.C. Electrical Characteristics
(TA = – 25°C to + 70°C (C), – 40°C to + 85°C (I), VCC = 1.8 V to 5.5 V)
Parameter Symbol Conditions VCC = 1.8 to 5.5 V
(Standard Mode) VCC = 2.5 to 5.5 V
(Fast Mode) Unit
Min Max Min Max
External clock frequency FCLK – 0 100 0 400 kHz
Clock high time tHIGH – 4 – 0.6 –µs
Clock low time tLOW –4.7 –1.3 –
Rising time tRSDA, SCL –1–0.3
Falling time tFSDA, SCL –0.3 –0.3
Start condition hold time tHD:STA – 4 – 0.6 –
Start condition setup time tSU:STA –4.7 –0.6 –
Data input hold time tHD:DAT – 0–0–
Data input setup time tSU:DAT –0.25 –0.1 –
Stop condition setup time tSU:STO – 4 – 0.6 –
Bus free time tBUF Before new
transmission 4.7 –1.3 –
Data output valid from
clock low (note) tAA –0.3 3.5 –0.9
Noise spike width tSP – – 100 – 50 ns
Write cycle time tWR – –5–5ms
NOTES:
1. Upon customers request, up to 400 kHz (Max.) in standard mode and 1 MHz in fast mode are available.
2. When acting as a transmitter, the S524A40X10/40X20/40X40 must provide an internal minimum delay time to bridge
the undefined period (minimum 300 ns) of the falling edge of SCL. This is required to avoid unintended generation of a
start or stop condition.
DATA SHEET S524A40X10/40X20/40X40 SERIAL EEPROM
2-17
SCL tLOW
tFtR
SDA In
tSU:STA tHD:STA tHD:DAT tSU:DAT tSU:STO
tHIGH
SDA Out
tBUFtAA
Figure 2-16. Timing Diagram for Bus Operations
8th Bit
WORDn
SCL
SDA
Start
Condition
~
~~
~~
~
tWR
Stop
Condition
ACK
~
~
Figure 2-17. Write Cycle Timing Diagram
S524A40X10/40X20/40X40 SERIAL EEPROM DATA SHEET
2-18
NOTES
