TSSOP8 (DW)
169 mil width
SO8N (MN)
150 mil width
UFDFPN8 (MC)
DFN8 - 2x3 mm
WLSCP (CU)
WLSCP (CS)
Unsawn wafer
Features
• Compatible with following I2C bus modes:
– 1 MHz
– 400 kHz
– 100 kHz
• Memory array:
– 256 Kbit (32 Kbyte) of EEPROM
– Page size: 64 byte
– Additional write lockable page (M24256-D order codes)
• Single supply voltage and high speed:
– 1 MHz clock from 1.7 V to 5.5 V
• Write:
– Byte write within 5 ms
– Page write within 5 ms
• Operating temperature range:
– from -40 °C up to +85 °C
• Random and sequential read modes
• Write protect of the whole memory array
• Enhanced ESD/latch-Up protection
• More than 4 million write cycles
• More than 200-years data retention
Packages
• RoHS-compliant and Halogen-free (ECOPACK2)
• SO8 ECOPACK2
• TSSOP8 ECOPACK2
• UFDFPN8 ECOPACK2
• WLCSP ECOPACK2
• Unsawn wafer (each die is tested)
Product status link
M24256-BF
M24256-DF
M24256-BR
M24256-DR
M24256-BW
256-Kbit serial I²C bus EEPROM
M24256-BW M24256-BR M24256-BF
M24256-DR M24256-DF
Datasheet
DS1766 - Rev 35 - November 2020
For further information contact your local STMicroelectronics sales office.
www.st.com
1Description
The M24256 is a 256-Kbit I2C-compatible EEPROM (electrically erasable programmable memory) organized as
32 K × 8 bits.
The M24256-BW can operate with a supply voltage from 2.5 V to 5.5 V, the M24256-BR AND M24256-DR can
operate with a supply voltage from 1.8 V to 5.5 V, and the M24256-BF and M24256-DF can operate with a supply
voltage from 1.7 V to 5.5 V. All these devices operate with a clock frequency of 1 MHz (or less), over an ambient
temperature range of –40 °C / +85 °C. The M24256-D offers an additional page, named the identification page
(64 byte). The identification page can be used to store sensitive application parameters which can be (later)
permanently locked in read-only mode.
Figure 1. Logic diagram
3
E0-E2 SDA
VCC
M24xxx
WC
SCL
VSS
Table 1. Signal names
Signal name Function Direction
E2, E1, E0 Chip enable Input
SDA Serial data I/O
SCL Serial clock Input
WC Write control Input
VCC Supply voltage -
VSS Ground -
Figure 2. 8-pin package connections, top view
SDA
VSS
SCL
WCE1
E0 VCC
E2
1
2
3
4
8
7
6
5
1. See Section 9 Package information for package dimensions, and how to identify pin 1
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Description
DS1766 - Rev 35 page 2/47
Figure 3. WLCSP connections
E1
E0
E2
SCL
SDA
VSS
VCC
WC
E0
SDA
SCL
VCC
WC
E1
E2
VSS
Marking side
(top view)
Bump side
(bottom view)
1 2 3
A
B
C
D
E
A
B
C
D
E
12
3
Table 2. Signal vs. bump position
Position A B C D E
1 WC - VCC - SCL
2 - E0 - SDA -
3 E1 - VSS - E2
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Description
DS1766 - Rev 35 page 3/47
2Signal description
2.1 Serial clock (SCL)
The signal applied on the SCL input is used to strobe the data available on SDA(in) and to output the data on
SDA(out).
2.2 Serial data (SDA)
SDA is an input/output used to transfer data in or data out of the device. SDA(out) is an open drain output
that may be wire-OR’ed with other open drain or open collector signals on the bus. A pull-up resistor must be
connected from serial data (SDA) to VCC (Figure 12 indicates how to calculate the value of the pull-up resistor).
2.3 Chip enable (E2, E1, E0)
(E2,E1,E0) input signals are used to set the value that is to be looked for on the three least significant bits (b3, b2,
b1) of the 7-bit device select code (see Table 3). These inputs must be tied to VCC or VSS, as shown in Figure 4.
When not connected (left floating), these inputs are read as low (0).
Figure 4. Chip enable inputs connection
VCC
M24xxx
VSS
Ei
VCC
M24xxx
VSS
Ei
2.4 Write control (WC)
This input signal is useful for protecting the entire contents of the memory from inadvertent write operations. Write
operations are disabled to the entire memory array when write control (WC) is driven high. Write operations are
enabled when write control (WC) is either driven low or left floating.
When write control (WC) is driven high, device select and address bytes are acknowledged, data bytes are not
acknowledged.
2.5 VSS (ground)
VSS is the reference for the VCC supply voltage.
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Signal description
DS1766 - Rev 35 page 4/47
2.6 Supply voltage (VCC)
2.6.1 Operating supply voltage (VCC)
Prior to selecting the memory and issuing instructions to it, a valid and stable VCC voltage within the specified
[VCC(min), VCC(max)] range must be applied (see Operating conditions in Section 8 DC and AC parameters). In
order to secure a stable DC supply voltage, it is recommended to decouple the VCC line with a suitable capacitor
(usually of the order of 10 nF to 100 nF) close to the VCC/VSS package pins.
This voltage must remain stable and valid until the end of the transmission of the instruction and, for a write
instruction, until the completion of the internal write cycle (tW).
2.6.2 Power-up conditions
The VCC voltage has to rise continuously from 0 V up to the minimum VCC operating voltage (see Operating
conditions in Section 8 DC and AC parameters).
2.6.3 Device reset
In order to prevent inadvertent write operations during power-up, a power-on-reset (POR) circuit is included.
At power-up, the device does not respond to any instruction until VCC has reached the internal reset
threshold voltage. This threshold is lower than the minimum VCC operating voltage (see Operating conditions
in Section 8 DC and AC parameters). When VCC passes over the POR threshold, the device is reset and enters
the standby power mode; however, the device must not be accessed until VCC reaches a valid and stable DC
voltage within the specified [VCC(min), VCC(max)] range (see Operating conditions in Section 8 DC and AC
parameters).
In a similar way, during power-down (continuous decrease in VCC), the device must not be accessed when VCC
drops below VCC(min). When VCC drops below the power-on-reset threshold voltage, the device stops responding
to any instruction sent to it.
2.6.4 Power-down conditions
During power-down (continuous decrease in VCC), the device must be in the standby power mode (mode reached
after decoding a stop condition, assuming that there is no internal write cycle in progress).
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
Supply voltage (VCC)
DS1766 - Rev 35 page 5/47
3Memory organization
The memory is organized as shown below.
Figure 5. Block diagram
HV GENERATOR
+
SEQUENCER
I/O
ARRAY
SENSE AMPLIFIERS
Y DECODER
DATA REGISTER
+
ECC
CONTROL
LOGIC
SCL
SDA
IDENTIFICATION PAGE
PAGE LATCHES X DECODER
START & STOP
DETECT
ADDRESS
REGISTER
WC
Ei
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Memory organization
DS1766 - Rev 35 page 6/47
4Device operation
The device supports the I2C protocol. This is summarized in Figure 6. Any device that sends data on to the bus
is defined to be a transmitter, and any device that reads the data to be a receiver. The device that controls the
data transfer is known as the bus master, and the other as the slave device. A data transfer can only be initiated
by the bus master, which will also provide the serial clock for synchronization. The device is always a slave in all
communications.
Figure 6. I2C bus protocol
SCL
SDA
SCL
SDA
SDA
START
Condition
SDA
Input
SDA
Change STOP
Condition
1 2 3 7 8 9
MSB ACK
START
Condition
SCL 1 2 3 7 8 9
MSB ACK
STOP
Condition
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Device operation
DS1766 - Rev 35 page 7/47
4.1 Start condition
Start is identified by a falling edge of serial data (SDA) while serial clock (SCL) is stable in the high state. A start
condition must precede any data transfer instruction. The device continuously monitors (except during a write
cycle) serial data (SDA) and serial clock (SCL) for a start condition.
4.2 Stop condition
Stop is identified by a rising edge of serial data (SDA) while serial clock (SCL) is stable and driven high. A stop
condition terminates communication between the device and the bus master. A read instruction that is followed by
NoAck can be followed by a stop condition to force the device into the standby mode.
A stop condition at the end of a write instruction triggers the internal write cycle.
4.3 Data input
During data input, the device samples serial data (SDA) on the rising edge of serial clock (SCL). For correct
device operation, serial data (SDA) must be stable during the rising edge of serial clock (SCL), and the serial data
(SDA) signal must change only when serial clock (SCL) is driven low.
4.4 Acknowledge bit (ACK)
The acknowledge bit is used to indicate a successful byte transfer. The bus transmitter, whether it be bus master
or slave device, releases serial data (SDA) after sending eight bits of data. During the 9th clock pulse period, the
receiver pulls serial data (SDA) low to acknowledge the receipt of the eight data bits.
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Start condition
DS1766 - Rev 35 page 8/47
4.5 Device addressing
To start communication between the bus master and the slave device, the bus master must initiate a Start
condition. Following this, the bus master sends the device select code, shown in Table 3 (most significant bit first).
Table 3. Device select code
Device type identifier(1) Chip Enable address(2) RW
b7 b6 b5 b4 b3 b2 b1 b0
Device select code when addressing the memory array 1 0 1 0 E2 E1 E0 RW
Device select code when accessing the Identification page 1 0 1 1 E2 E1 E0 RW
1. The most significant bit, b7, is sent first.
2. E0, E1 and E2 are compared with the value read on input pins E0, E1 and E2.
When the device select code is received, the device only responds if the chip enable address is the same as the
value on the chip enable (E2, E1, E0) inputs.
The 8th bit is the Read/Write bit (RW). This bit is set to 1 for read and 0 for write operations.
If a match occurs on the device select code, the corresponding device gives an acknowledgement on serial data
(SDA) during the 9th bit time. If the device does not match the device select code, it deselects itself from the bus,
and goes into standby mode.
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Device addressing
DS1766 - Rev 35 page 9/47
5Instructions
5.1 Write operations
Following a start condition the bus master sends a device select code with the R/W bit (RW) reset to 0. The
device acknowledges this, as shown in Figure 7, and waits for two address bytes. The device responds to each
address byte with an acknowledge bit, and then waits for the data byte.
Table 4. Most significant address byte
A15 A14 A13 A12 A11 A10 A9 A8
Table 5. Least significant address byte
A7 A6 A5 A4 A3 A2 A1 A0
When the bus master generates a stop condition immediately after a data byte Ack bit (in the “10th bit” time slot),
either at the end of a byte write or a page write, the internal write cycle tW is triggered. A stop condition at any
other time slot does not trigger the internal write cycle.
After the stop condition and the successful completion of an internal write cycle (tW), the device internal address
counter is automatically incremented to point to the next byte after the last modified byte.
During the internal write cycle, serial data (SDA) is disabled internally, and the device does not respond to any
requests.
If the write control input (WC) is driven high, the write instruction is not executed and the accompanying data
bytes are not acknowledged, as shown in Figure 8.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
Instructions
DS1766 - Rev 35 page 10/47
5.1.1 Byte write
After the device select code and the address bytes, the bus master sends one data byte. If the addressed location
is write-protected, by write control (WC) being driven high, the device replies with NoAck, and the location is not
modified. If, instead, the addressed location is not write-protected, the device replies with Ack. The bus master
terminates the transfer by generating a stop condition, as shown in Figure 7.
Figure 7. Write mode sequences with WC = 0 (data write enabled)
WC
Byte Write Dev sel Byte addr Byte addr Data in
ACK ACK ACK ACK
RW
Start
Stop
WC
Dev sel Byte addr Byte addr
ACK ACK ACK ACK
RW
Start
Data in 1 Data in 2
Page Write
Page Write (cont’d)
WC (cont’d)
ACK ACK
Data in N
Stop
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Write operations
DS1766 - Rev 35 page 11/47
5.1.2 Page write
The page write mode allows up to 64 byte to be written in a single write cycle, provided that they are all located
in the same page in the memory: that is, the most significant memory address bits, A15/A6, are the same. If more
bytes are sent than will fit up to the end of the page, a “roll-over” occurs, i.e. the bytes exceeding the page end
are written on the same page, from location 0.
The bus master sends from 1 to 64 byte of data, each of which is acknowledged by the device if write control
(WC) is low. If write control (WC) is high, the contents of the addressed memory location are not modified, and
each data byte is followed by a NoAck, as shown in Figure 8. After each transferred byte, the internal page
address counter is incremented.
The transfer is terminated by the bus master generating a stop condition.
Figure 8. Write mode sequences with WC = 1 (data write inhibited)
Page write
Page write (cont’d)
WC (cont’d)
WC
WC
Byte write
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Write operations
DS1766 - Rev 35 page 12/47
5.1.3 Write identification page (M24256-D only)
The identification page (64 byte) is an additional page which can be written and (later) permanently locked in
read-only mode. It is written by issuing the write identification page instruction. This instruction uses the same
protocol and format as page write (into memory array), except for the following differences:
• Device type identifier = 1011b
• MSB address bits A15/A6 are don't care except for address bit A10 which must be ‘0’. LSB address bits
A5/A0 define the byte address inside the Identification page.
If the identification page is locked, the data bytes transferred during the write identification page instruction are not
acknowledged (NoAck).
5.1.4 Lock identification page (M24256-D only)
The lock identification page instruction (Lock ID) permanently locks the identification page in read-only mode. The
lock ID instruction is similar to byte write (into memory array) with the following specific conditions:
• Device type identifier = 1011b
• Address bit A10 must be ‘1’; all other address bits are don't care
• The data byte must be equal to the binary value xxxx xx1x, where x is don't care
5.1.5 ECC (error correction code) and write cycling
The error correction code (ECC) is an internal logic function which is transparent for the I2C communication
protocol.
The ECC logic is implemented on each group of four EEPROM bytes (A group of four bytes is located at
addresses [4*N, 4*N+1, 4*N+2, 4*N+3], where N is an integer). Inside a group, if a single bit out of the four bytes
happens to be erroneous during a read operation, the ECC detects this bit and replaces it with the correct value.
The read reliability is therefore much improved.
Even if the ECC function is performed on groups of four bytes, a single byte can be written/cycled independently.
In this case, the ECC function also writes/cycles the three other bytes located in the same group (A group of
four bytes is located at addresses [4*N, 4*N+1, 4*N+2, 4*N+3], where N is an integer). As a consequence, the
maximum cycling budget is defined at group level and the cycling can be distributed over the 4 bytes of the group:
the sum of the cycles seen by byte0, byte1, byte2 and byte3 of the same group must remain below the maximum
value defined Table 11.
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Write operations
DS1766 - Rev 35 page 13/47
5.1.6 Minimizing write delays by polling on ACK
The maximum write time (tw) is shown in AC characteristics tables in Section 8 , but the typical time is shorter. To
make use of this, a polling sequence can be used by the bus master.
The sequence, as shown in Figure 9, is:
• Initial condition: a write cycle is in progress.
• Step 1: the bus master issues a Start condition followed by a device select code (the first byte of the new
instruction).
• Step 2: if the device is busy with the internal write cycle, no Ack is returned and the bus master goes back
to step 1. If the device has terminated the internal write cycle, it responds with an Ack, indicating that the
device is ready to receive the second part of the instruction (the first byte of this instruction having been sent
during Step 1).
Figure 9. Write cycle polling flowchart using ACK
Write cycle
in progress
Next
operation is
addressing the
memory
Start condition
ACK
returned
YES
NO
YESNO
Re-start
Stop
Data for the
write operation
Send address
and receive ACK
YESNO
Continue the
write operation
Continue the
random read operation
Device select
with RW = 1
First byte of instruction
with RW = 0 already
decoded by the device
Device select
with RW = 0
StartCondition
1. The seven most significant bits of the device select code of a random read (bottom right box in the figure)
must be identical to the seven most significant bits of the device select code of the write (polling instruction
in the figure).
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Write operations
DS1766 - Rev 35 page 14/47
5.2 Read operations
Read operations are performed independently of the state of the write control (WC) signal.
After the successful completion of a read operation, the device internal address counter is incremented by one, to
point to the next byte address.
For the read instructions, after each byte read (data out), the device waits for an acknowledgement (data in)
during the 9th bit time. If the bus master does not acknowledge during this 9th time, the device terminates the data
transfer and switches to its standby mode.
Figure 10. Read mode sequences
Start
Dev sel * Byte addr Byte addr
Start
Dev sel Data out 1
Data out N
Stop
Start
Current
Address
Read
Dev sel Data out
Random
Address
Read
Stop
Start
Dev sel * Data out
Sequential
Current
Read
Stop
Data out N
Start
Dev sel * Byte addr Byte addr
Sequential
Random
Read
Start
Dev sel * Data out1
Stop
ACK
RW
NO ACK
ACK
RW
ACK ACK ACK
RW
ACK ACK ACK NO ACK
RW
NO ACK
ACK ACK ACK
RW
ACK ACK
RW
ACK NO ACK
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Read operations
DS1766 - Rev 35 page 15/47
5.2.1 Random address read
A dummy write is first performed to load the address into this address counter (as shown in Figure 10) but without
sending a stop condition. Then, the bus master sends another start condition, and repeats the device select code,
with the RW bit set to 1. The device acknowledges this, and outputs the contents of the addressed byte. The bus
master must not acknowledge the byte, and terminates the transfer with a stop condition.
5.2.2 Current address read
For the current address read operation, following a start condition, the bus master only sends a device select
code with the R/W bit set to 1. The device acknowledges this, and outputs the byte addressed by the internal
address counter. The counter is then incremented. The bus master terminates the transfer with a stop condition,
as shown in Figure 10, without acknowledging the byte.
Note that the address counter value is defined by instructions accessing either the memory or the identification
page. When accessing the Identification page, the address counter value is loaded with the byte location in the
identification page, therefore the next current address read in the memory uses this new address counter value.
When accessing the memory, it is safer to always use the random address read instruction (this instruction loads
the address counter with the byte location to read in the memory, see Section 5.2.1 Random address read)
instead of the current address Read instruction.
5.2.3 Sequential read
This operation can be used after a current address read or a random address read. The bus master does
acknowledge the data byte output, and sends additional clock pulses so that the device continues to output the
next byte in sequence. To terminate the stream of bytes, the bus master must not acknowledge the last byte, and
must generate a Stop condition, as shown in Figure 10.
The output data comes from consecutive addresses, with the internal address counter automatically incremented
after each byte output. After the last memory address, the address counter “rolls-over”, and the device continues
to output data from memory address 00h.
5.3 Read identification page (M24256-D only)
The identification page (64 bytes) is an additional page which can be written and (later) permanently locked in
Read-only mode.
The identification page can be read by issuing an read identification page instruction. This instruction uses the
same protocol and format as the random address read (from memory array) with device type identifier defined as
1011b. The MSB address bits A15/A6 are don't care, the LSB address bits A5/A0 define the byte address inside
the identification page. The number of bytes to read in the ID page must not exceed the page boundary (e.g.:
when reading the identification page from location 10d, the number of bytes should be less than or equal to 54, as
the ID page boundary is 64 bytes).
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
Read identification page (M24256-D only)
DS1766 - Rev 35 page 16/47
5.4 Read the lock status (M24256-D only)
The locked/unlocked status of the identification page can be checked by transmitting a specific truncated
command [identification page write instruction + one data byte] to the device. The device returns an acknowledge
bit if the identification page is unlocked, otherwise a NoAck bit if the identification page is locked.
Right after this, it is recommended to transmit to the device a start condition followed by a stop condition, so that:
• Start: the truncated command is not executed because the start condition resets the device internal logic,
• Stop: the device is then set back into standby mode by the stop condition.
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Read the lock status (M24256-D only)
DS1766 - Rev 35 page 17/47
6Initial delivery state
The device is delivered with all the memory array bits and Identification page bits set to 1 (each byte contains
FFh).
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Initial delivery state
DS1766 - Rev 35 page 18/47
7Maximum rating
Stressing the device outside the ratings listed in Table 6 may cause permanent damage to the device. These
are stress ratings only, and operation of the device at these, or any other conditions outside those indicated in
the operating sections of this specification, is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
Table 6. Absolute maximum ratings
Symbol Parameter Min. Max. Unit
- Ambient operating temperature -40 130 °C
TSTG Storage temperature –65 150 °C
TLEAD Lead temperature during soldering see note (1) °C
IOL DC output current (SDA = 0) – 5 mA
VIO Input or output range –0.50 6.5 V
VCC Supply voltage -0.50 6.5 V
VESD Electrostatic pulse (Human Body model)(2) – 4000 V
1. Compliant with JEDEC Std J-STD-020D (for small body, Sn-Pb or Pb-free assembly), the ST ECOPACK 7191395
specification, and the European directive on Restrictions of Hazardous Substances (RoHS directive 2011/65/EU of July
2011).
2. Positive and negative pulses applied on different combinations of pin connections, according to AEC-Q100-002 (compliant
with ANSI/ESDA/JEDEC JS-001-2012 standard, C1=100 pF, R1=1500 Ω).
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
Maximum rating
DS1766 - Rev 35 page 19/47
8DC and AC parameters
This section summarizes the operating and measurement conditions, and the DC and AC characteristics of the
device.
Table 7. Operating conditions (voltage range W)
Symbol Parameter Min. Max. Unit
VCC Supply voltage 2.5 5.5 V
TAAmbient operating temperature –40 85 °C
fCOperating clock frequency - 1 MHz
Table 8. Operating conditions (voltage range R)
Symbol Parameter Min. Max. Unit
VCC Supply voltage 1.8 5.5 V
TAAmbient operating temperature –40 85 °C
fCOperating clock frequency - 1 MHz
Table 9. Operating conditions (voltage range F)
Symbol Parameter Min. Max. Unit
VCC Supply voltage 1.7 5.5 V
TAAmbient operating temperature -40 85 °C
fCOperating clock frequency - 1 MHz
Table 10. AC measurement conditions
Symbol Parameter Min. Max. Unit
Cbus Load capacitance - 100 pF
-SCL input rise/fall time, SDA input fall time - 50 ns
-Input levels 0.2 VCC to 0.8 VCC V
-Input and output timing reference levels 0.3 VCC to 0.7 VCC V
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DC and AC parameters
DS1766 - Rev 35 page 20/47
Figure 11. AC measurement I/O waveform
0.8V
CC
0.2VCC
0.7VCC
0.3VCC
Input and output
Timing reference levels
Input voltage levels
Table 11. Input parameters
Symbol Parameter(1) Test condition Min. Max. Unit
CIN Input capacitance (SDA) - - 8 pF
CIN Input capacitance (other pins) - - 6 pF
ZL
Input impedance (E2, E1, E0, WC)(2)
VIN < 0.3 VCC 30 - kΩ
ZHVIN > 0.7 VCC 500 - kΩ
1. Characterized only, not tested in production.
2. E2, E1, E0 input impedance when the memory is selected (after a Start condition).
Table 12. Cycling performance by groups of four bytes
Symbol Parameter Test condition Max. Unit
Ncycle Write cycle endurance(1)
TA ≤ 25 °C, VCC(min) < VCC < VCC(max) 4,000,000
Write cycle(2)
TA = 85 °C, VCC(min) < VCC < VCC(max) 1,200,000
1. The write cycle endurance is defined by characterization and qualification. For devices embedding the ECC functionality
(see ECC (error correction code) and write cycling), the write cycle endurance is defined for group of four bytes located at
addresses [4*N, 4*N+1, 4*N+2, 4*N+3] where N is an integer.
2. A Write cycle is executed when either a page write, a byte write, a write identification page or a lock identification
page instruction is decoded. When using the byte write, the page write or the write identification page, refer also to
Section 5.1.5 ECC (error correction code) and write cycling
Table 13. Memory cell data retention
Parameter Test condition Min. Unit
Data retention(1) TA = 55 °C 200 Year
1. The data retention behaviour is checked in production, while the data retention limit defined in this table is extracted from
characterization and qualification results.
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DC and AC parameters
DS1766 - Rev 35 page 21/47
Table 14. DC characteristics (M24256-BW, device grade 6)
Symbol Parameter Test conditions (in addition to those in Table 7) Min. Max. Unit
ILI
Input leakage current
(SCL, SDA, E2, E1, E0)
VIN = VSS or VCC, device in Standby mode - ± 2 µA
ILO Output leakage current SDA in Hi-Z, external voltage applied on SDA: VSS or VCC - ± 2 µA
ICC Supply current (Read)
VCC = 2.5 V, fC = 400 kHz
(rise/fall time < 50 ns)
- 1
mA
VCC = 5.5 V, fC = 400 kHz
(rise/fall time < 50 ns)
- 2
2.5 V ≤VCC ≤ 5.5 V, fC = 1 MHz
(rise/fall time < 50 ns)
- 2.5
ICC0 Supply current (Write)
During tW,
2.5 V ≤ VCC ≤ 5.5 V -2(1) mA
ICC1 Standby supply current
Device not selected(2),
VIN = VSS or VCC, VCC = 2.5 V - 2 μA
Device not selected(2),
VIN = VSS or VCC, VCC = 5.5 V - 3 μA
VIL
Input low voltage(3)
(SCL, SDA, WC, E2, E1, E0)
- –0.45 0.3 VCC V
VIH
Input high voltage
(SCL, SDA) -0.7 VCC 6.5 V
Input high voltage
(WC, E2, E1, E0)(4) -0.7 VCC VCC+0.6 V
VOL Output low voltage
IOL = 2.1 mA, VCC = 2.5 V or
IOL = 3 mA, VCC = 5.5 V - 0.4 V
1. Characterized value, not tested in production.
2. The device is not selected after power-up, after a read instruction (after the stop condition), or after the completion of the
internal write cycle tW (tW is triggered by the correct decoding of a write instruction).
3. Ei inputs should be tied to Vss (see Section 2.3 Chip enable (E2, E1, E0)).
4. Ei inputs should be tied to Vcc (see Section 2.3 Chip enable (E2, E1, E0)).
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
DC and AC parameters
DS1766 - Rev 35 page 22/47
Table 15. DC characteristics (M24256-BR, M24256-DR device grade 6)
Symbol Parameter Test conditions (1)(in addition to those in Table 8)Min. Max. Unit
ILI
Input leakage current
( E0, E1, E2, SCL, SDA)
VIN = VSS or VCC, device in Standby mode - ± 2 µA
ILO Output leakage current SDA in Hi-Z, external voltage applied on SDA: VSS or
VCC - ± 2 µA
ICC Supply current (Read)
VCC = 1.8 V, fc= 400 kHz - 0.8 mA
fc= 1 MHz - 2.5 mA
ICC0 Supply current (Write)
During tW
1.8 V ≤ VCC ≤ 2.5 V -2(2) mA
ICC1 Standby supply current Device not selected,(3)
VIN = VSS or VCC, VCC = 1.8 V - 1 µA
VIL Input low voltage (SCL, SDA,
WC,E2, E1, E0)(4) 1.8 V ≤ VCC < 2.5 V -0.45 0.25 VCC V
VIH
Input high voltage
(SCL, SDA)
1.8 V ≤ VCC < 2.5 V 0.75 VCC 6.5 V
Input high voltage
(WC, E2, E1, E0(5))
1.8 V ≤ VCC < 2.5 V 0.75 VCC VCC+0.6 V
VOL Output low voltage IOL = 1 mA, VCC = 1.8 V - 0.2 V
1. If the application uses the voltage range R device with 2.5 V < Vcc < 5.5 V and -40 °C < TA < +85 °C, please refer to
Table 14 instead of this table.
2. Characterized value, not tested in production.
3. The device is not selected after power-up, after a read instruction (after the stop condition), or after the completion of the
internal write cycle tW (tW is triggered by the correct decoding of a write instruction).
4. Ei inputs should be tied to VSS (see Section 2.3 Chip enable (E2, E1, E0)).
5. Ei inputs should be tied to VCC (see Section 2.3 Chip enable (E2, E1, E0)).
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
DC and AC parameters
DS1766 - Rev 35 page 23/47
Table 16. DC characteristics (M24256-BF, M24256-DF, device grade 6)
Symbol Parameter Test conditions(1) (in addition to those in Table 9)Min. Max. Unit
ILI
Input leakage current
(E0, E1, E2, SCL, SDA)
VIN = VSS or VCC
device in Standby mode
- ± 2 µA
ILO Output leakage current SDA in Hi-Z, external voltage applied on SDA: VSS or
VCC - ± 2 µA
ICC Supply current (Read)
VCC = 1.7 V, fc= 400 kHz - 0.8
mA
fc= 1 MHz - 2.5
ICC0 Supply current (Write)
During tW
1.7 V < VCC < 2.5 V -2(2) mA
ICC1 Standby supply current Device not selected,(3)
VIN = VSS or VCC, VCC = 1.7 V - 1 µA
VIL Input low voltage (SCL, SDA,
WC,E2, E1, E0)(4) 1.7 V ≤ VCC < 2.5 V -0.45 0.25 VCC V
VIH
Input high voltage
(SCL, SDA)
1.7 V ≤ VCC < 2.5 V 0.75 VCC 6.5 V
Input high voltage
(WC, E2, E1, E0)(5) 1.7 V ≤ VCC < 2.5 V 0.75 VCC VCC+0.6 V
VOL Output low voltage IOL = 1 mA, VCC = 1.7 V - 0.2 V
1. If the application uses the voltage range F device with 2.5 V < VCC < 5.5 V and -40 °C < TA < +85 °C, please refer to
Table 14 instead of this table.
2. Characterized value, not tested in production.
3. The device is not selected after power-up, after a read instruction (after the stop condition), or after the completion of the
internal write cycle tW (tW is triggered by the correct decoding of a write instruction).
4. Ei inputs should be tied to VSS (see Section 2.3 Chip enable (E2, E1, E0)).
5. Ei inputs should be tied to VCC (see Section 2.3 Chip enable (E2, E1, E0)).
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
DC and AC parameters
DS1766 - Rev 35 page 24/47
Table 17. 400 kHz AC characteristics
Symbol Alt. Parameter Min. Max. Unit
fCfSCL Clock frequency - 400 kHz
tCHCL tHIGH Clock pulse width high 600 - ns
tCLCH tLOW Clock pulse width low 1300 - ns
tQL1QL2(1) tFSDA (out) fall time 20(2) 300 ns
tXH1XH2 tRInput signal rise time (3) (3) ns
tXL1XL2 tFInput signal fall time (3) (3) ns
tDXCH tSU:DAT Data in set up time 100 - ns
tCLDX tHD:DAT Data in hold time 0 - ns
tCLQX(4) tDH Data out hold time 100 - ns
tCLQV(5) tAA Clock low to next data valid (access time) - 900 ns
tCHDL tSU:STA Start condition setup time 600 - ns
tDLCL tHD:STA Start condition hold time 600 - ns
tCHDH tSU:STO Stop condition set up time 600 - ns
tDHDL tBUF Time between Stop condition and next Start condition 1300 - ns
tWLDL(1)(6) tSU:WC WC set up time (before the Start condition) 0 - µs
tDHWH(1)(7) tHD:WC WC hold time (after the Stop condition) 1 - µs
tWtWR Internal Write cycle duration - 5 ms
tNS(1) - Pulse width ignored (input filter on SCL and SDA) - single glitch - 80 ns
1. Characterized only, not tested in production.
2. With CL = 10 pF.
3. There is no min. or max. values for the input signal rise and fall times. It is however recommended by the I²C specification
that the input signal rise and fall times be more than 20 ns and less than 300 ns when fC < 400 kHz.
4. To avoid spurious Start and Stop conditions, a minimum delay is placed between SCL=1 and the falling or rising edge of
SDA.
5. tCLQV is the time (from the falling edge of SCL) required by the SDA bus line to reach either 0.3VCC or 0.7VCC, assuming
that Rbus × Cbus time constant is within the values specified in Figure 12.
6. WC=0 set up time condition to enable the execution of a WRITE command.
7. WC=0 hold time condition to enable the execution of a WRITE command.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
DC and AC parameters
DS1766 - Rev 35 page 25/47
Table 18. 1 MHz AC characteristics
Symbol Alt. Parameter Min. Max. Unit
fCfSCL Clock frequency 0 1 MHz
tCHCL tHIGH Clock pulse width high 260 - ns
tCLCH tLOW Clock pulse width low 500 - ns
tXH1XH2 tRInput signal rise time (1) (1) ns
tXL1XL2 tFInput signal fall time (1) (1) ns
tQL1QL2(2) tFSDA (out) fall time 20(3) 120 ns
tDXCH tSU:DAT Data in setup time 50 - ns
tCLDX tHD:DAT Data in hold time 0 - ns
tCLQX(4) tDH Data out hold time 100 - ns
tCLQV(5) tAA Clock low to next data valid (access time) - 450 ns
tCHDL tSU:STA Start condition setup time 250 - ns
tDLCL tHD:STA Start condition hold time 250 - ns
tCHDH tSU:STO Stop condition setup time 250 - ns
tDHDL tBUF Time between Stop condition and next Start condition 500 - ns
tWLDL(2)(6) tSU:WC WC set up time (before the Start condition) 0 - µs
tDHWH(2)(7) tHD:WC WC hold time (after the Stop condition) 1 - µs
tWtWR Write time - 5 ms
tNS(2) - Pulse width ignored (input filter on SCL and SDA) - 50 ns
1. There is no min. or max. values for the input signal rise and fall times. It is however recommended by the I²C specification
that the input signal rise and fall times be less than 120 ns when fC < 1 MHz.
2. Characterized only, not tested in production.
3. With CL = 10 pF.
4. To avoid spurious Start and Stop conditions, a minimum delay is placed between SCL=1 and the falling or rising edge of
SDA.
5. tCLQV is the time (from the falling edge of SCL) required by the SDA bus line to reach either 0.3 VCC or 0.7 VCC, assuming
that the Rbus × Cbus time constant is within the values specified in Figure 13.
6. WC=0 set up time condition to enable the execution of a WRITE command.
7. WC=0 hold time condition to enable the execution of a WRITE command.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
DC and AC parameters
DS1766 - Rev 35 page 26/47
Figure 12. Maximum Rbus value versus bus parasitic capacitance (Cbus) for an I2C bus at maximum
frequency fC = 400 kHz
1
10
100
10 100 1000
Bus line capacitor (pF)
I²C bus
master M24xxx
Rbus
VCC
Cbus
SCL
SDA
Rbus×Cbus= 400 ns
Here Rbus x Cbus = 120 ns
4 k
30
The Rbus x Cbus time constant
must be below the 400 ns
time constant line represented
on the left.
Bus line pull-up resistor (kΩ)
Figure 13. Maximum Rbus value versus bus parasitic capacitance (Cbus) for an I2C bus at maximum
frequency fC = 1MHz
1
10
0
I²C bus
master M24xxx
SCL
SDA
Here,
Rbus x Cbus = 150 ns
4
30
10
Rbus x Cbus = 120 ns
Bus line capacitor (pF)
10 100
The Rbus x Cbus time constant
Must be below the 150 ns
Time constant line
represented on the left
Bus line pull-up resistor (kΩ )
VCC
Rbus
Cbus
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
DC and AC parameters
DS1766 - Rev 35 page 27/47
Figure 14. AC waveforms
SCL
SDA Out
SCL
SDA In
Data valid
tCLQV tCLQX
tCHDH
Stop
condition
tCHDL
Start
condition
Write cycle
tW
Data valid
tQL1QL2
SDA In
tCHDL
Start
condition
tDXCHtCLDX
SDA
Input SDA
Change
tCHDH tDHDL
Stop
condition
Start
condition
tXH1XH2
SCL
tCHCL
tDLCL
tCLCHtXH1XH2 tXL1XL2
tXL1XL2
WC
tWLDL tDHWH
tCHCL
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
DC and AC parameters
DS1766 - Rev 35 page 28/47
9Package information
In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK®
packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions
and product status are available at: www.st.com. ECOPACK® is an ST trademark.
For die information concerning the M24256-BF delivered in unsawn wafer, please contact your nearest ST Sales
Office.
9.1 UFDFPN8 (DFN8) package information
UFDFPN8 is an 8-lead, 2 × 3 mm, 0.55 mm thickness ultra thin profile fine pitch dual flat package.
Figure 15. UFDFPN8 - Outline
Top view
Pin #1
ID marking
Side view
Seating plane
eee
ccc
C
C
C
C
C
B
A
12
N
D
E
aaa
aaa
A
A1
A3
2x
2x
Datum A
Terminal tip
Detail “A”
Even terminal
L1
L3L
e
e/2
Pin #1
ID marking
Bottom view See Detail “A”
e
e
1 2
ND-1 x
D2
L1
L3
E2
K
L
b
1. Maximum package warpage is 0.05 mm.
2. Exposed copper is not systematic and can appear partially or totally according to the cross section.
3. Drawing is not to scale.
4. The central pad (the area E2 by D2 in the above illustration) must be either connected to VSS or left floating
(not connected) in the end application.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
Package information
DS1766 - Rev 35 page 29/47
Table 19. UFDFPN8 - Mechanical data
Symbol
millimeters inches(1)
Min Typ Max Min Typ Max
A0.450 0.550 0.600 0.0177 0.0217 0.0236
A1 0.000 0.020 0.050 0.0000 0.0008 0.0020
b(2) 0.200 0.250 0.300 0.0079 0.0098 0.0118
D 1.900 2.000 2.100 0.0748 0.0787 0.0827
D2 1.200 - 1.600 0.0472 - 0.0630
E 2.900 3.000 3.100 0.1142 0.1181 0.1220
E2 1.200 - 1.600 0.0472 - 0.0630
e - 0.500 - 0.0197
K 0.300 - - 0.0118 - -
L 0.300 - 0.500 0.0118 - 0.0197
L1 - - 0.150 - - 0.0059
L3 0.300 - - 0.0118 - -
aaa - - 0.150 - - 0.0059
bbb - - 0.100 - - 0.0039
ccc - - 0.100 - - 0.0039
ddd - - 0.050 - - 0.0020
eee(3) - - 0.080 - - 0.0031
1. Values in inches are converted from mm and rounded to four decimal digits.
2. Dimension b applies to plated terminal and is measured between 0.15 and 0.30 mm from the terminal tip.
3. Applied for exposed die paddle and terminals. Exclude embedding part of exposed die paddle from measuring.
Figure 16. UFDFPN8 - Recommended footprint
0.500
1.400
0.600
1.200
0.300
1.300
1. Dimensions are expressed in millimeters.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
UFDFPN8 (DFN8) package information
DS1766 - Rev 35 page 30/47
9.2 TSSOP8 package information
TSSOP8 is an 8-lead thin shrink small outline, 3 x 6.4 mm, 0.65 mm pitch, package.
Figure 17. TSSOP8 – Outline
1
CP
c
L
E
D
α
e
4
L1
E1
A2
A
b
8 5
A1
1. Drawing is not to scale.
Table 20. TSSOP8 – Mechanical data
Symbol
millimeters inches (1)
Min. Typ. Max. Min. Typ. Max.
A- - 1.200 - - 0.0472
A1 0.050 - 0.150 0.0020 - 0.0059
A2 0.800 1.000 1.050 0.0315 0.0394 0.0413
b 0.190 - 0.300 0.0075 - 0.0118
c 0.090 - 0.200 0.0035 - 0.0079
CP - - 0.100 - - 0.0039
D 2.900 3.000 3.100 0.1142 0.1181 0.1220
e - 0.650 - - 0.0256 -
E 6.200 6.400 6.600 0.2441 0.2520 0.2598
E1 4.300 4.400 4.500 0.1693 0.1732 0.1772
L 0.450 0.600 0.750 0.0177 0.0236 0.0295
L1 - 1.000 - - 0.0394 -
α 0° - 8° 0° - 8°
1. Values in inches are converted from mm and rounded to four decimal digits.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
TSSOP8 package information
DS1766 - Rev 35 page 31/47
Figure 18. TSSOP8 – Recommended footprint
2.3
1.0
0.65
0.35
7.0
1. Dimensions are expressed in millimeters.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
TSSOP8 package information
DS1766 - Rev 35 page 32/47
9.3 SO8N package information
SO8N is an 8-lead, 4.9 x 6 mm, plastic small outline, 150 mils body width, package.
Figure 19. SO8N – Outline
E1
8
ccc
b
D
c
1
E
h x 45˚
A2
k
0.25 mm
L
A1
GAUGE PLANE
e
A
L1
1. Drawing is not to scale.
Table 21. SO8N – Mechanical data
Symbol
millimeters inches (1)
Min. Typ. Max. Min. Typ. Max.
A- - 1.750 - - 0.0689
A1 0.100 - 0.250 0.0039 - 0.0098
A2 1.250 - - 0.0492 - -
b 0.280 - 0.480 0.0110 - 0.0189
c 0.170 - 0.230 0.0067 - 0.0091
D 4.800 4.900 5.000 0.1890 0.1929 0.1969
E 5.800 6.000 6.200 0.2283 0.2362 0.2441
E1 3.800 3.900 4.000 0.1496 0.1535 0.1575
e - 1.270 - - 0.0500 -
h 0.250 - 0.500 0.0098 - 0.0197
k 0° - 8° 0° - 8°
L 0.400 - 1.270 0.0157 - 0.0500
L1 - 1.040 - - 0.0409 -
ccc - - 0.100 - - 0.0039
1. Values in inches are converted from mm and rounded to four decimal digits.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
SO8N package information
DS1766 - Rev 35 page 33/47
Figure 20. SO8N - Recommended footprint
1.27
0.6 (x8)
3.9
6.7
1. Dimensions are expressed in millimeters.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
SO8N package information
DS1766 - Rev 35 page 34/47
9.4 WLCSP8 (CS) package information
WLCSP8 is a 8 bumps, 1.289 x 1.379 mm, 0.4 mm pitch wafer level chip scale package
Figure 21. WLCSP8 - Outline
(4X)
aaa
Wafer back side
D
E
Side view
Detail A
A2
A
e1
e2
e
G
F
Bump side
H
e3
bbb Z
XY
Reference
Orientation
Detail A
Rotated 90 °
A1
Bump
Seating plane
Z
eee Z
Z
Z
X
ccc M Y
Ø
Øddd M
b
1. Drawing is not to scale
2. Primary datum Z and seating plane are defined by the spherical crowns of the bump.
3. Bump position designation per JESD 95-1, SPP-010.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
WLCSP8 (CS) package information
DS1766 - Rev 35 page 35/47
Table 22. WLCSP8 - Mechanical data
Symbol
millimeters inches(1)
Min Typ Max Min Typ Max
A0.500 0.540 0.580 0.0197 0.0213 0.0228
A1 - 0.190 - - 0.0075 -
A2 - 0.350 - - 0.0138 -
b(2) - 0.270 - - 0.0106 -
D - 1.289 1.309 - 0.0507 0.0515
E - 1.379 1.399 - 0.0542 0.0550
e - 0.800 - - 0.0315 -
e1 - 0.693 - - 0.0273 -
e2 - 0.400 - - 0.0157 -
e3 - 0.400 - - 0.0157 -
F - 0.342 - - 0.0135 -
G - 0.245 - - 0.0096 -
H - 0.245 - - 0.0096 -
aaa - 0.110 - - 0.0043 -
bbb - 0.110 - - 0.0043 -
ccc - 0.110 - - 0.0043 -
ddd - 0.060 - - 0.0024 -
eee - 0.060 - - 0.0024 -
1. Values in inches are converted from mm and rounded to four decimal digits.
2. Dimension is measured at the maximum bump diameter parallel to primary datum Z.
Figure 22. WLCSP8 - Recommended footprint
0.693
0.400
0.800
0.400
8 bumps x Ø 0.270
1. Dimensions are expressed in millimeters.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
WLCSP8 (CS) package information
DS1766 - Rev 35 page 36/47
9.5 WLCSP8 (CU) package information
This WLCSP is a 8 balls, 1.289 x 1.376 mm, 0.4 mm pitch, with BSC, wafer level chip scale package
Figure 23. WLCSP8 - Outline
X
Y
D
E
aaa
(2X)
Orientation reference
TOP VIEW
b
A1 A
A2
A3
Backside protection
Detail A
bbb Z
e
e1
e2 e3
G
F
2
1
3
ABCDE
Orientation reference
SIDE VIEW BOTTOM VIEW
aaa
(2X)
Z
ccc
ddd
M
MZ
Z X Y
b
Detail A
Rotated 90
Seating plane
A1
bbb Z
1. Drawing is not to scale.
2. Dimension is measured at the maximum bump diameter parallel to primary datum Z.
3. Primary datum Z and seating plane are defined by the spherical crowns of the bump.
4. Bump position designation per JESD 95-1, SPP-010.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
WLCSP8 (CU) package information
DS1766 - Rev 35 page 37/47
Table 23. WLCSP8 - Mechanical data
Millimeters inches(1)
Min Typ Max Min Typ Max
A0.255 0.295 0.335 0.0100 0.0116 0.0132
A1 - 0.095 - - 0.0037 -
A2 - 0.175 - - 0.0069 -
A3 - 0.025 - - 0.0010 -
b - 0.185 - - 0.0073 -
D - 1.289 1.309 - 0.0507 0.0515
E - 1.376 1.396 - 0.0542 0.0550
e - 0.400 - - 0.0157 -
e1 - 0.800 - - 0.0315 -
e2 - 0.346 - - 0.0136 -
e3 - 0.693 - - 0.0273 -
F - 0.342 - - 0.0135 -
G - 0.245 - - 0.0096 -
aaa - 0.110 - - 0.0043 -
bbb - 0.110 - - 0.0043 -
ccc - 0.110 - - 0.0043 -
ddd - 0.060 - - 0.0024 -
eee - 0.060 - - 0.0024 -
1. Values in inches are converted from mm and rounded to the 4rd decimal place
Figure 24. WLCSP8 - Recommended footprint
0.693
0.800
0.400
0.346
8 bumps x 0.185
1. Dimensions are expressed in millimeters.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
WLCSP8 (CU) package information
DS1766 - Rev 35 page 38/47
10 Ordering information
Table 24. Ordering information scheme
Example: M24 256 - D W MN 6 T P /K
Device type
M24 = I2C serial access EEPROM
Device function
256 = 256 Kbit (32 K x 8 bit)
Device family
B = Without identification page
D = With identification page
Operating voltage
W = VCC = 2.5 V to 5.5 V
R = VCC = 1.8 V to 5.5 V
F = VCC = 1.7 V to 5.5 V
Package(1)
MN = SO8 (150 mil width)
DW = TSSOP8 (169 mil width)
MC = UFDFPN8 (DFN8)
CS = WLCSP (chip scale package)
CU = WLCSP Ultra-thin
Device grade
6 = Industrial: device tested with standard test flow over -40 to 85 °C
Option
T = Tape and reel packing
blank = tube packing
Plating technology
P or G = ECOPACK2
Process(2)
/K = Manufacturing technology code
1. ECOPACK2 (RoHS compliant and free of brominated, chlorinated and antimony oxide flame retardants).
2. These process letters appear on the device package (marking) and on the shipment box. Contact your nearest ST Sales
Office for further information
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
Ordering information
DS1766 - Rev 35 page 39/47
Table 25. Ordering information scheme (unsawn wafer)
Example: M24 256 - B F K W 20 I /90
Device type(1)
M24 = I2C serial access EEPROM
Device function
256 = 256 Kbit (32 K x 8 bit)
Device family
B = Without identification page
Operating voltage
F = VCC = 1.7 V to 5.5 V
Process
K = F8H
Delivery form
W =Unsawn wafer
Wafer thickness
20 = Non-backlapped wafer
Wafer testing
I = Inkless test
Device grade
90 = -40°C to 85°C
1. For all information concerning the M24256 delivered in unsawn wafer, please contact your nearest ST Sales Office.
Note: Parts marked as ES or E or accompanied by an Engineering Sample notification letter are not yet qualified
and therefore not approved for use in production. ST is not responsible for any consequences resulting from
such use. In no event will ST be liable for the customer using any of these engineering samples in production.
ST’s Quality department must be contacted prior to any decision to use these engineering samples to run a
qualification activity.
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
Ordering information
DS1766 - Rev 35 page 40/47
Revision history
Table 26. Document revision history
Date Revision Changes
22-Jun-2012 26
Datasheet revision 25 split into:
– M24256-125 datasheet for automotive products (range 3),
– M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF (this
datasheet) for standard products (range 6).
Added:
– Reference M24256-DF
– Table 1: Signal names, Table 12: Memory cell data retention
Updated:
– Table 17: 400 kHz AC characteristics and Table 18: 1 MHz AC
characteristics: added set up and hold timing conditions on WC (tWLDL and
tDHWH)
– Figure 18: M24256-DFCS6TP/K, WLCSP 8-bump wafer-level chip scale
package outline and Table 21: M24256-DFCS6TP/K, WLCSP 8- bump wafer-
level chip scale package mechanical data
– Cycling and data retention limits
Deleted:
– UFDFPN8, package revision MB
01-Aug-2012 27 Updated Figure 3: WLCSP connections and Figure 18: M24256-DFCS6TP/K,
WLCSP 8-bump wafer-level chip scale package outline.
18-Sep-2012 28 Changed title of Figure 3: WLCSP connections.
Updated Section 5.2.2: Current Address Read.
20-Nov-2012 29 Corrected “Device family” data in Table 24: Ordering information scheme.
17-Dec-2012 30
Deleted note (3) under Table 3: Device select code.
Modified ICCO condition in Table 15: DC characteristics (M24256-BR,
M24256-DR device grade 6).
Deleted incorrect table (Table 15. DC characteristics (M24256-R, device grade
6)).
Updated package list in Table 24: Ordering information scheme.
21-Feb-2014 31
Updated Figure 3: WLCSP connections.
Added notes 4. and 5. in Table 14 and notes 5. and 6. in Table 15 and Table
16
17-Jun-2014 32
Updated
– Figure 3,
– note 1 on Table 12
– In Table 24 note 1 on Package and blank reference on Option.
01-Jun-2015 33
Added:
– Unsawn wafer reference on cover page and Table 25: Ordering information
scheme (unsawn wafer)
– Figure 20: WLCSP (CS) - 8-bump, 1.289 x 1.376 mm, 0.4 mm pitch wafer
level chip scale package recommended footprint
– reference to Engineering samples
Updated:
– Section 2.6.2, Section 4.5
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
DS1766 - Rev 35 page 41/47
Date Revision Changes
– Note 2 on Table 6
– Table 18
– Note 2 on Figure 15
– Table 21
– Note 2 on Table 24
Removed:
– Note on tNS max value on Table 18
14-Mar-2018 34
Added WLCSP (CU) package in cover page and in Section 9: Package
information, Table 2: Signals vs. bump position.
Updated Table 10: AC measurement conditions, Table 22: WLCSP (CS)-
8-bump, 1.289 x 1.376 mm, 0.4 mm pitch wafer level chip scale package
mechanical data, Table 24: Ordering information scheme
19-Nov-2020 35
Updated:
•Figure 5. Block diagram,
•Table 6. Absolute maximum ratings, Table 12. Cycling performance by
groups of four bytes, Table 14. DC characteristics (M24256-BW, device
grade 6), Table 15. DC characteristics (M24256-BR, M24256-DR device
grade 6), Table 16. DC characteristics (M24256-BF, M24256-DF, device
grade 6), Table 18. 1 MHz AC characteristics,
• note 1 in Table 13. Memory cell data retention
• title of Figure 17. TSSOP8 – Outline andTable 20. TSSOP8 –
Mechanical data; Figure 19. SO8N – Outline, Table 21. SO8N
– Mechanical data and Figure 20. SO8N - Recommended
footprint; Figure 21. WLCSP8 - Outline, Table 22. WLCSP8 -
Mechanical data and Figure 22. WLCSP8 - Recommended footprint;
Figure 23. WLCSP8 - Outline, Table 23. WLCSP8 - Mechanical data
and Figure 24. WLCSP8 - Recommended footprint
Added:
• , Figure 18. TSSOP8 – Recommended footprint
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
DS1766 - Rev 35 page 42/47
Contents
1Description ........................................................................2
2Signal description .................................................................4
2.1 Serial Clock (SCL)..............................................................4
2.2 Serial Data (SDA) ..............................................................4
2.3 Chip Enable (E2, E1, E0) ........................................................4
2.4 Write Control (WC) .............................................................4
2.5 VSS (ground) ..................................................................4
2.6 Supply voltage (VCC) ...........................................................5
2.6.1 Operating supply voltage (VCC) .............................................5
2.6.2 Power-up conditions ......................................................5
2.6.3 Device reset ............................................................5
2.6.4 Power-down conditions ....................................................5
3Memory organization ..............................................................6
4Device operation ..................................................................7
4.1 Start condition .................................................................8
4.2 Stop condition .................................................................8
4.3 Data input.....................................................................8
4.4 Acknowledge bit (ACK)..........................................................8
4.5 Device addressing..............................................................9
5Instructions ......................................................................10
5.1 Write operations ..............................................................10
5.1.1 Byte Write .............................................................11
5.1.2 Page Write ............................................................12
5.1.3 Write identification page (M24256-D only).....................................13
5.1.4 Lock identification page (M24256-D only) .....................................13
5.1.5 ECC (Error Correction Code) and Write cycling ................................13
5.1.6 Minimizing Write delays by polling on ACK ....................................14
5.2 Read operations ..............................................................15
5.2.1 Random Address Read...................................................16
5.2.2 Current Address Read ...................................................16
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
Contents
DS1766 - Rev 35 page 43/47
5.2.3 Sequential Read ........................................................16
5.3 Read identification page (M24256-D only).........................................16
5.4 Read the lock status (M24256-D only) ............................................17
6Initial delivery state ...............................................................18
7Maximum rating ..................................................................19
8DC and AC parameters ...........................................................20
9Package information..............................................................29
9.1 UFDFPN8 (DFN8) package information...........................................29
9.2 TSSOP8 package information ...................................................31
9.3 SO8N package information .....................................................33
9.4 WLCSP8 (CS) package information ..............................................35
9.5 WLCSP8 (CU) package information ..............................................37
10 Ordering information .............................................................39
Revision history .......................................................................41
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
Contents
DS1766 - Rev 35 page 44/47
List of tables
Table 1. Signal names ......................................................................2
Table 2. Signal vs. bump position ...............................................................3
Table 3. Device select code...................................................................9
Table 4. Most significant address byte........................................................... 10
Table 5. Least significant address byte .......................................................... 10
Table 6. Absolute maximum ratings ............................................................ 19
Table 7. Operating conditions (voltage range W) ................................................... 20
Table 8. Operating conditions (voltage range R) .................................................... 20
Table 9. Operating conditions (voltage range F) .................................................... 20
Table 10. AC measurement conditions ........................................................... 20
Table 11. Input parameters ................................................................... 21
Table 12. Cycling performance by groups of four bytes ................................................ 21
Table 13. Memory cell data retention ............................................................ 21
Table 14. DC characteristics (M24256-BW, device grade 6)............................................. 22
Table 15. DC characteristics (M24256-BR, M24256-DR device grade 6) .................................... 23
Table 16. DC characteristics (M24256-BF, M24256-DF, device grade 6) .................................... 24
Table 17. 400 kHz AC characteristics ............................................................ 25
Table 18. 1 MHz AC characteristics ............................................................. 26
Table 19. UFDFPN8 - Mechanical data ........................................................... 30
Table 20. TSSOP8 – Mechanical data ........................................................... 31
Table 21. SO8N – Mechanical data ............................................................. 33
Table 22. WLCSP8 - Mechanical data............................................................ 36
Table 23. WLCSP8 - Mechanical data............................................................ 38
Table 24. Ordering information scheme........................................................... 39
Table 25. Ordering information scheme (unsawn wafer) ............................................... 40
Table 26. Document revision history ............................................................. 41
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
List of tables
DS1766 - Rev 35 page 45/47
List of figures
Figure 1. Logic diagram.....................................................................2
Figure 2. 8-pin package connections, top view .....................................................2
Figure 3. WLCSP connections ................................................................3
Figure 4. Chip enable inputs connection .........................................................4
Figure 5. Block diagram ....................................................................6
Figure 6. I2C bus protocol ...................................................................7
Figure 7. Write mode sequences with WC = 0 (data write enabled) ...................................... 11
Figure 8. Write mode sequences with WC = 1 (data write inhibited)...................................... 12
Figure 9. Write cycle polling flowchart using ACK .................................................. 14
Figure 10. Read mode sequences ............................................................. 15
Figure 11. AC measurement I/O waveform ....................................................... 21
Figure 12. Maximum Rbus value versus bus parasitic capacitance (Cbus) for an I2C bus at maximum frequency fC = 400 kHz
.............................................................................. 27
Figure 13. Maximum Rbus value versus bus parasitic capacitance (Cbus) for an I2C bus at maximum frequency fC = 1MHz 27
Figure 14. AC waveforms ................................................................... 28
Figure 15. UFDFPN8 - Outline ................................................................ 29
Figure 16. UFDFPN8 - Recommended footprint .................................................... 30
Figure 17. TSSOP8 – Outline ................................................................ 31
Figure 18. TSSOP8 – Recommended footprint..................................................... 32
Figure 19. SO8N – Outline .................................................................. 33
Figure 20. SO8N - Recommended footprint ....................................................... 34
Figure 21. WLCSP8 - Outline................................................................. 35
Figure 22. WLCSP8 - Recommended footprint..................................................... 36
Figure 23. WLCSP8 - Outline................................................................. 37
Figure 24. WLCSP8 - Recommended footprint..................................................... 38
M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
List of figures
DS1766 - Rev 35 page 46/47
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M24256-BW M24256-BR M24256-BF M24256-DR M24256-DF
DS1766 - Rev 35 page 47/47
