24AA64/24FC64/24LC64
64-Kbit I2C Serial EEPROM
Device Selection Table
Part Number
24AA64
VCC Range
Max. Clock
Frequency
Temp. Ranges
1.7V-5.5V
400 kHz(1)
I, E
MHz(2)
24FC64
1.7V-5.5V
1
24LC64
2.5V-5.5V
400 kHz
Note 1:
2:
Packages
CS, MC, MS, P, SN, SM, OT, MNY, ST, X/ST
I
MC, MF, MS, P, SN, SM, OT, MNY, ST
I, E
MC, MS, P, SN, SM, OT, MNY, ST, X/ST
100 kHz for VCC < 2.5V
400 kHz for VCC < 2.5V
Features
Packages
• Single Supply with Operation Down to 1.7V for
24AA64 and 24FC64 Devices and 2.5V for
24LC64 Devices
• Low-Power CMOS Technology:
- Active current: 3 mA, maximum
- Standby current: 1 µA, maximum
• Two-Wire Serial Interface, I2C Compatible
• Packages with Three Address Pins are
Cascadable Up to Eight Devices
• Schmitt Trigger Inputs for Noise Suppression
• Output Slope Control to Eliminate Ground Bounce
• 100 kHz and 400 kHz Clock Compatibility
• 1 MHz Clock for FC versions
• Page Write Time: 5 ms, Maximum
• Self-Timed Erase/Write Cycle
• 32-Byte Page Write Buffer
• Hardware Write-Protect
• ESD Protection > 4,000V
• More Than 1 Million Erase/Write Cycles
• Data Retention > 200 Years
• Factory Programming Available
• RoHS Compliant
• Temperature Ranges Supported:
- Industrial (I):
-40C to +85C
- Extended (E):
-40C to +125C
• 5-Lead Chip Scale, 8-Lead DFN, 8-Lead DFN-S,
8-Lead MSOP, 8-Lead PDIP, 8-Lead SOIC,
8-Lead SOIJ, 5-Lead SOT-23, 8-Lead TDFN,
8-Lead TSSOP and 8-Lead X-Rotated TSSOP
Description
The Microchip Technology Inc. 24XX64(1) is a 64-Kbit
Electrically Erasable PROM (EEPROM). The device is
organized as a single block of 8K x 8-bit memory with
a two-wire serial interface. Its low-voltage design
permits operation down to 1.7V, with standby and
active currents of only 1 µA and 3 mA, respectively.
The 24XX64 also has a page write capability for up to
32 bytes of data. Functional address lines allow up to
eight devices on the same bus, for up to 512-Kbit
address space.
Note 1: 24XX64 is used in this document as a
generic
part
number
for
the
24AA64/24FC64/24LC64 devices.
• Automotive AEC-Q100 Qualified
Package Types
CS (Chip Scale)
VCC
WP
SCL
1
2
(1)
VSS
3
4
5
SDA
DFN/TDFN
A0 1
A1 2
A2 3
VSS 4
MSOP/PDIP/SOIC/SOIJ/TSSOP
A0
1
8
VCC
A1
2
7
WP
6 SCL
A2
3
6
SCL
5 SDA
VSS
4
5
SDA
8 VCC
7 WP
SOT-23
SCL
1
VSS
2
SDA
3
5
WP
4
WP
VCC
A0
VCC A1
X-Rotated TSSOP
(X/ST)
1
2
3
4
8
7
6
5
SCL
SDA
VSS
A2
(Top Down View,
Balls Not Visible)
Note
1:
Available in I-temp, “AA” only.
1997-2022 Microchip Technology Inc. and its subsidiaries
DS20001189U-page 1
24AA64/24FC64/24LC64
Block Diagram
HV
Generator
A0 A1 A2 WP
I/O
Control
Logic
Memory
Control
Logic
XDEC
EEPROM
Array
Page
Latches
I/O
SCL
YDEC
SDA
VCC
VSS
DS20001189U-page 2
Sense Amp.
R/W Control
1997-2022 Microchip Technology Inc. and its subsidiaries
24AA64/24FC64/24LC64
1.0
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings (†)
VCC.............................................................................................................................................................................6.5V
All inputs and outputs w.r.t. VSS ..........................................................................................................-0.3V to VCC +1.0V
Storage temperature ............................................................................................................................... -65°C to +150°C
Ambient temperature with power applied................................................................................................ -40°C to +125°C
ESD protection on all pins 4 kV
† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above those
indicated in the operational listings of this specification is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
TABLE 1-1:
DC CHARACTERISTICS
DC CHARACTERISTICS
Param.
Symbol
No.
Characteristic
Min.
Typical
Max.
Units
0.7 VCC
—
—
V
—
—
0.3 VCC
V
VCC 2.5V
—
—
0.2 VCC
V
VCC 2.5V
0.05 VCC
—
—
V
VCC 2.5V (Note 1)
D1
VIH
High-Level Input Voltage
D2
VIL
Low-Level Input Voltage
D3
VHYS
Hysteresis of Schmitt
Trigger Inputs
(SDA, SCL pins)
D4
VOL
Low-Level Output Voltage
D5
ILI
Input Leakage Current
D6
ILO
D7
CIN,
COUT
D8
ICC Write
D9
ICC Read
D10
Note 1:
2:
ICCS
Electrical Characteristics:
Industrial (I): TA = -40°C to +85°C, VCC = +1.7V to +5.5V
Extended (E): TA = -40°C to +125°C, VCC = +1.7V to +5.5V
Conditions
—
—
0.40
V
IOL = 3.0 mA @ VCC = 4.5V
—
—
0.40
V
IOL = 2.1 mA @ VCC = 2.5V
—
—
±1
µA
VIN = VSS or VCC, WP = VSS
—
—
±1
µA
VIN = VSS or VCC, WP = VCC
Output Leakage Current
—
—
±1
µA
VOUT = VSS or VCC
Pin Capacitance
(all inputs/outputs)
—
—
10
pF
VCC = 5.0V (Note 1)
TA = 25°C, FCLK = 1 MHz
—
0.1
3
mA
VCC = 5.5V, SCL = 400 kHz
—
0.05
400
µA
VCC = 5.5V, SCL = 400 kHz
—
0.01
1
µA
SDA = SCL = VCC
A0, A1, A2, WP = VSS, I-Temp.
—
—
5
µA
SDA = SCL = VCC
A0, A1, A2, WP = VSS, E-Temp.
Operating Current
Standby Current
This parameter is periodically sampled and not 100% tested.
Typical measurements taken at room temperature.
1997-2022 Microchip Technology Inc. and its subsidiaries
DS20001189U-page 3
24AA64/24FC64/24LC64
TABLE 1-2:
AC CHARACTERISTICS
Electrical Characteristics:
Industrial (I): VCC = +1.7V to +5.5V TA = -40°C to +85°C
Extended (E): VCC = +1.7V to +5.5V TA = -40°C to +125°C
AC CHARACTERISTICS
Param.
Symbol
No.
1
FCLK
2
THIGH
3
TLOW
4
TR
5
TF
Characteristic
Clock Frequency
Clock High Time
Clock Low Time
SDA and SCL Rise Time
SDA and SCL Fall Time
THD:STA Start Condition Hold Time
6
TSU:STA Start Condition Setup Time
7
Min.
Max.
Units
Conditions
—
100
kHz
1.7V VCC 2.5V
—
400
kHz
2.5V VCC 5.5V
—
400
kHz
1.7V VCC 2.5V (24FC64)
2.5V VCC 5.5V (24FC64)
—
1000
kHz
4000
—
ns
1.7V VCC 2.5V
600
—
ns
2.5V VCC 5.5V
600
—
ns
1.7V VCC 2.5V (24FC64)
500
—
ns
2.5V VCC 5.5V (24FC64)
4700
—
ns
1.7V VCC 2.5V
1300
—
ns
2.5V VCC 5.5V
1300
—
ns
1.7V VCC 2.5V (24FC64)
500
—
ns
2.5V VCC 5.5V (24FC64)
—
1000
ns
1.7V VCC 2.5V (Note 1)
—
300
ns
2.5V VCC 5.5V (Note 1)
—
300
ns
1.7V VCC 5.5V (24FC64)
(Note 1)
—
300
ns
24AA64 and 24LC64 (Note 1)
—
100
ns
1.7V VCC 5.5V (24FC64)
(Note 1)
4000
—
ns
1.7V VCC 2.5V
600
—
ns
2.5V VCC 5.5V
600
—
ns
1.7V VCC 2.5V (24FC64)
250
—
ns
2.5V VCC 5.5V (24FC64)
4700
—
ns
1.7V VCC 2.5V
600
—
ns
2.5V VCC 5.5V
600
—
ns
1.7V VCC 2.5V (24FC64)
250
—
ns
2.5V VCC 5.5V (24FC64)
—
ns
Note 2
8
THD:DAT Data Input Hold Time
0
250
—
ns
1.7V VCC 2.5V
9
TSU:DAT Data Input Setup Time
100
—
ns
2.5V VCC 5.5V
TSU:STO Stop Condition Setup Time
10
Note 1:
2:
3:
4:
100
—
ns
1.7V VCC 5.5V (24FC64)
4000
—
ns
1.7V VCC 2.5V
600
—
ns
2.5V VCC 5.5V
600
—
ns
1.7V VCC 2.5V (24FC64)
250
—
ns
2.5V VCC 5.5V (24FC64)
Not 100% tested. CB = total capacitance of one bus line in pF.
As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region
(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
The combined TSP and VHYS specifications are due to new Schmitt Trigger inputs, which provide
improved noise spike suppression. This eliminates the need for a TI specification for standard operation.
This parameter is not tested but ensured by characterization.
DS20001189U-page 4
1997-2022 Microchip Technology Inc. and its subsidiaries
24AA64/24FC64/24LC64
TABLE 1-2:
AC CHARACTERISTICS
Electrical Characteristics:
Industrial (I): VCC = +1.7V to +5.5V TA = -40°C to +85°C
Extended (E): VCC = +1.7V to +5.5V TA = -40°C to +125°C
AC CHARACTERISTICS
Param.
Symbol
No.
11
TSU:WP
THD:WP
12
13
TAA
14
TBUF
Characteristic
WP Setup Time
WP Hold Time
Output Valid from Clock
Bus Free Time: The time the
bus must be free before a new
transmission can start
Min.
Max.
Units
4000
—
ns
1.7V VCC 2.5V
600
—
ns
2.5V VCC 5.5V
600
—
ns
1.7V VCC 5.5V (24FC64)
4700
—
ns
1.7V VCC 2.5V
1300
—
ns
2.5V VCC 5.5V
1300
—
ns
1.7V VCC 5.5V 24FC64
—
3500
ns
1.7V VCC 2.5V (Note 2)
—
900
ns
2.5V VCC 5.5V (Note 2)
—
900
ns
1.7V VCC 2.5V (24FC64)
(Note 2)
—
400
ns
2.5V VCC 5.5V (24FC64)
(Note 2)
4700
—
ns
1.7V VCC 2.5V
1300
—
ns
2.5V VCC 5.5V
1300
—
ns
1.7V VCC 2.5V (24FC64)
500
—
ns
2.5V VCC 5.5V (24FC64)
10 + 0.1CB
250
ns
24AA64 and 24LC64 (Note 1)
—
250
ns
24FC64 (Note 1)
24AA64 and 24LC64
(Note 1 and Note 3)
15
TOF
Output Fall Time from VIH
Minimum to VIL Maximum
CB 100 pF
16
TSP
Input Filter Spike Suppression
(SDA and SCL pins)
—
50
ns
17
TWC
Write Cycle Time
(byte or page)
—
5
ms
1,000,000
—
cycles
18
Endurance
Note 1:
2:
3:
4:
Conditions
+25°C, 5.5V, Page Mode
(Note 4)
Not 100% tested. CB = total capacitance of one bus line in pF.
As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region
(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
The combined TSP and VHYS specifications are due to new Schmitt Trigger inputs, which provide
improved noise spike suppression. This eliminates the need for a TI specification for standard operation.
This parameter is not tested but ensured by characterization.
1997-2022 Microchip Technology Inc. and its subsidiaries
DS20001189U-page 5
24AA64/24FC64/24LC64
FIGURE 1-1:
BUS TIMING DATA
5
SCL
SDA
IN
7
3
4
D3
2
8
10
9
6
16
14
13
SDA
OUT
WP
DS20001189U-page 6
(protected)
(unprotected)
11
12
1997-2022 Microchip Technology Inc. and its subsidiaries
24AA64/24FC64/24LC64
2.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1:
PIN FUNCTION TABLE
DFN(1) MSOP PDIP SOIC SOIJ SOT-23 TDFN(1) TSSOP
Rotated
TSSOP
Name
CS
A0
—
1
1
1
1
1
—
1
1
3
Chip Address Input
A1
—
2
2
2
2
2
—
2
2
4
Chip Address Input
A2
—
3
3
3
3
3
—
3
3
5
Chip Address Input
VSS
2
4
4
4
4
4
2
4
4
6
Ground
Description
SDA
5
5
5
5
5
5
3
5
5
7
Serial Address/Data I/O
SCL
4
6
6
6
6
6
1
6
6
8
Serial Clock
WP
3
7
7
7
7
7
5
7
7
1
Write-Protect Input
VCC
1
8
8
8
8
8
4
8
8
2
Power Supply
Note 1:
2.1
The exposed pad on the DFN/TDFN packages can be connected to VSS or left floating.
A0, A1, A2 Chip Address Inputs
The A0, A1 and A2 inputs are used by the 24XX64 for
multiple device operation. The levels on these inputs
are compared with the corresponding bits in the client
address. The chip is selected if the compare is true.
Up to eight devices may be connected to the same bus
by using different Chip Select bit combinations. These
inputs must be connected to either VCC or VSS.
In most applications, the chip address inputs A0, A1
and A2 are hard-wired to logic ‘0’ or logic ‘1’. For
applications in which these pins are controlled by a
microcontroller or other programmable device, the chip
address pins must be driven to logic ‘0’ or logic ‘1’
before normal device operation can proceed. Address
pins are not available in the SOT-23 or Chip Scale
packages.
2.2
2.3
Serial Clock (SCL)
The SCL input is used to synchronize the data transfer
from and to the device.
2.4
Write-Protect (WP)
This pin must be connected to either VSS or VCC. If tied
to VSS, write operations are enabled. If tied to VCC,
write operations are inhibited but read operations are
not affected.
Serial Address/Data Input/Output
(SDA)
SDA is a bidirectional pin used to transfer addresses
and data into and out of the device. Since it is an
open-drain terminal, the SDA bus requires a pull-up
resistor to VCC (typical 10 k for 100 kHz, 2 k for
400 kHz and 1 MHz).
For normal data transfer, SDA is allowed to change
only during SCL low. Changes during SCL high are
reserved for indicating the Start and Stop conditions.
1997-2022 Microchip Technology Inc. and its subsidiaries
DS20001189U-page 7
24AA64/24FC64/24LC64
3.0
FUNCTIONAL DESCRIPTION
The 24XX64 supports a bidirectional, two-wire bus and
data transmission protocol. A device that sends data
onto the bus is defined as transmitter, while a device
receiving data is defined as a receiver. The bus has to
be controlled by a host device which generates the
Serial Clock (SCL), controls the bus access and
generates the Start and Stop conditions, while the
24XX64 works as client. Both host and client can
operate as transmitter or receiver, but the host device
determines which mode is activated.
4.0
BUS CHARACTERISTICS
The following bus protocol has been defined:
• Data transfer may be initiated only when the bus
is not busy
• During data transfer, the data line must remain
stable whenever the clock line is high. Changes in
the data line while the clock line is high will be
interpreted as a Start or Stop condition
Accordingly, the following bus conditions have been
defined (Figure 4-1).
4.1
Start Data Transfer (B)
A high-to-low transition of the SDA line while the clock
(SCL) is high determines a Start condition. All
commands must be preceded by a Start condition.
4.3
Stop Data Transfer (C)
A low-to-high transition of the SDA line while the clock
(SCL) is high determines a Stop condition. All
operations must be ended with a Stop condition.
FIGURE 4-1:
(A)
Data Valid (D)
The state of the data line represents valid data when,
after a Start condition, the data line is stable for the
duration of the high period of the clock signal.
The data on the line must be changed during the low
period of the clock signal. There is one clock pulse per
bit of data.
Each data transfer is initiated with a Start condition and
terminated with a Stop condition. The number of data
bytes transferred between Start and Stop conditions is
determined by the host device and is, theoretically,
unlimited (although only the last 32 will be stored when
doing a write operation). When an overwrite does
occur, it will replace data in a First-In First-Out (FIFO)
principle.
4.5
Acknowledge
Each receiving device, when addressed, is obliged to
generate an Acknowledge after the reception of each
byte. The host device must generate an extra clock
pulse which is associated with this Acknowledge bit.
Note:
Bus Not Busy (A)
Both data and clock lines remain high.
4.2
4.4
The 24XX64 does not generate any
Acknowledge bits if an internal
programming cycle is in progress.
The device that acknowledges has to pull down the
SDA line during the Acknowledge clock pulse in such a
way that the SDA line is stable-low during the high
period of the Acknowledge-related clock pulse.
Moreover, setup and hold times must be taken into
account. During reads, a host must signal an end of
data to the client by not generating an Acknowledge bit
on the last byte that has been clocked out of the client.
In this case, the client (24XX64) will leave the data line
high to enable the host to generate the Stop condition.
DATA TRANSFER SEQUENCE ON THE SERIAL BUS
(B)
(D)
Start
Condition
Address or
Acknowledge
Valid
(D)
(C)
(A)
SCL
SDA
DS20001189U-page 8
Data
Allowed
to Change
Stop
Condition
1997-2022 Microchip Technology Inc. and its subsidiaries
24AA64/24FC64/24LC64
5.0
DEVICE ADDRESSING
FIGURE 5-1:
A control byte is the first byte received following the
Start condition from the host device. The control byte
consists of a 4-bit control code. For the 24XX64, this is
set as ‘1010’ binary for read and write operations. The
next three bits of the control byte are the Chip Select
bits (A2, A1, A0). The Chip Select bits allow the use of
up to eight 24XX64 devices on the same bus and are
used to select which device is accessed. The Chip
Select bits in the control byte must correspond to the
logic levels on the corresponding A2, A1 and A0 pins
for the device to respond. These bits are, in effect, the
three Most Significant bits of the word address. The
combination of the 4-bit control code and the next three
bits are called the client address.
For the SOT-23 and Chip Scale packages, the address
pins are not available. During device addressing, the
A2, A1 and A0 Chip Select bits should be set to ‘0’.
The last bit of the control byte is the Read/Write (R/W)
bit and it defines the operation to be performed. When
set to a ‘1’, a read operation is selected. When set to
a ‘0’, a write operation is selected. The next two bytes
received define the address of the first data byte
(Figure 5-2). Because only A12...A0 are used, the
upper three address bits are “don’t care” bits. The
upper address bits are transferred first, followed by the
Less Significant bits.
CONTROL BYTE FORMAT
Read/Write Bit
Chip Select
Bits
Control Code
S
1
0
1
0
A2
A1
A0 R/W ACK
Client Address
Start Bit
5.1
Acknowledge Bit
Contiguous Addressing Across
Multiple Devices
The Chip Select bits A2, A1 and A0 can be used to
expand the contiguous address space for up to
512 Kbits by adding up to eight 24XX64 devices on the
same bus. In this case, software can use A0 of the
control byte as address bit A13; A1 as address bit A14;
and A2 as address bit A15. It is not possible to
sequentially read across device boundaries.
The SOT-23 and Chip Scale packages do not support
multiple device addressing on the same bus.
Following the Start condition, the 24XX64 monitors the
SDA bus, checking the device-type identifier being
transmitted. Upon receiving a valid client address and
the R/W bit, the client device outputs an Acknowledge
signal on the SDA line. Depending on the state of the
R/W bit, the 24XX64 will select a read or write operation.
FIGURE 5-2:
ADDRESS SEQUENCE BIT ASSIGNMENTS
Control Byte
1
0
1
Control
Code
0
A
2
A
1
Address High Byte
A
0 R/W
x
Chip
Select
bits
1997-2022 Microchip Technology Inc. and its subsidiaries
x
x
A A A
12 11 10
Address Low Byte
A
9
A
8
A
7
•
•
•
•
•
•
A
0
x = “don’t care” bit
DS20001189U-page 9
24AA64/24FC64/24LC64
6.0
WRITE OPERATIONS
6.1
Byte Write
Following the Start condition from the host, the control
code (four bits), the Chip Select (three bits) and the
R/W bit (which is a logic low) are clocked onto the bus
by the host transmitter. This indicates to the addressed
client receiver that the address high byte will follow
once it has generated an Acknowledge bit during the
ninth clock cycle. Therefore, the next byte transmitted
by the host is the high-order byte of the word address
and will be written into the Address Pointer of the
24XX64.
The next byte is the Least Significant Address byte.
After receiving another Acknowledge signal from the
24XX64, the host device will transmit the data word to
be written into the addressed memory location. The
24XX64 acknowledges again and the host generates a
Stop condition. This initiates the internal write cycle
and, during this time, the 24XX64 will not generate
Acknowledge signals (Figure 6-1). If an attempt is
made to write to the array with the WP pin held high, the
device will acknowledge the command, but no write
cycle will occur, no data will be written and the device
will immediately accept a new command. After a byte
Write command, the internal Address Pointer will point
to the address location following the one that was just
written.
Note:
6.2
Page Write
The write control byte, word address and the first data
byte are transmitted to the 24XX64 in the same way as
in a byte write. However, instead of generating a Stop
condition, the host transmits up to 31 additional bytes
which are temporarily stored in the on-chip page buffer
and will be written into memory once the host has
transmitted a Stop condition. Upon receipt of each
word, the five lower Address Pointer bits, which form
the byte counter, are internally incremented by one.
The higher-order 8 bits of the word address remain
constant.
If the host should transmit more than 32 bytes prior to
generating the Stop condition, the Address Pointer will
roll over and the previously received data will be overwritten. As with the byte write operation, once the Stop
condition is received, an internal write cycle will begin
(Figure 6-2). If an attempt is made to write to the array
with the WP pin held high, the device will acknowledge
the command, but no write cycle will occur, no data will
be written and the device will immediately accept a new
command.
Note:
When doing a write of less than 32 bytes,
the data in the rest of the page are
refreshed along with the data bytes being
written. This will force the entire page to
endure a write cycle, for this reason
endurance is specified per page.
6.3
Page write operations are limited to
writing bytes within a single physical page,
regardless of the number of bytes
actually being written. Physical page
boundaries start at addresses that are
integer multiples of the page buffer size
(or ‘page size’) and end at addresses that
are integer multiples of page size – 1. If a
page write command attempts to write
across a physical page boundary, the
result is that the data wrap around to the
beginning of the current page (overwriting
data previously stored there), instead of
being written to the next page, as might be
expected. It is therefore necessary for the
application software to prevent page write
operations that would attempt to cross a
page boundary.
Write Protection
The WP pin allows the user to write-protect the entire
array (0000-1FFF) when the pin is tied to VCC. If tied to
VSS, the write protection is disabled. The WP pin is
sampled at the Stop bit for every Write command
(Figure 4-1). Toggling the WP pin after the Stop bit will
have no effect on the execution of the write cycle.
DS20001189U-page 10
1997-2022 Microchip Technology Inc. and its subsidiaries
24AA64/24FC64/24LC64
FIGURE 6-1:
BYTE WRITE
S
T
A
R
T
Bus Activity
Host
Control
Byte
Address
High Byte
AA
S1 010A
2 10 0
SDA Line
S
T
O
P
Data
xxx
P
A
C
K
Bus Activity
Address
Low Byte
A
C
K
A
C
K
A
C
K
x = “don’t care” bit
FIGURE 6-2:
PAGE WRITE
Bus Activity
Host
S
T
A
R
T
SDA Line
AA
S 101 0A
2 1 00
Bus Activity
Control
Byte
Address
High Byte
Address
Low Byte
Data Byte 0
S
T
O
P
Data Byte 31
P
xxx
A
C
K
A
C
K
A
C
K
A
C
K
A
C
K
x = “don’t care” bit
1997-2022 Microchip Technology Inc. and its subsidiaries
DS20001189U-page 11
24AA64/24FC64/24LC64
7.0
ACKNOWLEDGE POLLING
Since the device will not acknowledge during a write
cycle, this can be used to determine when the cycle is
complete (this feature can be used to maximize bus
throughput). Once the Stop condition for a write
command has been issued from the host, the device
initiates the internally-timed write cycle and ACK polling
can then be initiated immediately. This involves the
host sending a Start condition followed by the control
byte for a write command (R/W = 0). If the device is still
busy with the write cycle, then no ACK will be returned.
If no ACK is returned, the Start bit and control byte must
be resent. If the cycle is complete, the device will return
the ACK and the host can then proceed with the next
read or write operation. See Figure 7-1 for a flow
diagram of this operation.
FIGURE 7-1:
ACKNOWLEDGE POLLING
FLOW
Send
Write Command
Send Stop
Condition to
Initiate Write Cycle
Send Start
Send Control Byte
with R/W = 0
Did Device
Acknowledge
(ACK = 0)?
No
Yes
Next
Operation
DS20001189U-page 12
1997-2022 Microchip Technology Inc. and its subsidiaries
24AA64/24FC64/24LC64
8.0
READ OPERATION
Read operations are initiated in the same way as write
operations, with the exception that the R/W bit of the
control byte is set to one. There are three basic types
of read operations: current address read, random read
and sequential read.
8.1
Current Address Read
The 24XX64 contains an Address Pointer that maintains the address of the last word accessed, internally
incremented by one. Therefore, if the previous read
access was to address ‘n’ (n is any legal address), the
next current address read operation would access data
from address n + 1.
Upon receipt of the control byte with R/W bit set to one,
the 24XX64 issues an Acknowledge and transmits the
8-bit data word. The host will not acknowledge the
transfer, but does generate a Stop condition and the
24XX64 discontinues transmission (Figure 8-1).
8.2
Random Read
Random read operations allow the host to access
any memory location in a random manner. To
perform this type of read operation, the word address
must first be set. This is accomplished by sending
the word address to the 24XX64 as part of a write
operation (R/W bit set to ‘0’). Once the word address
is sent, the host generates a Start condition following
the Acknowledge.
FIGURE 8-1:
This terminates the write operation, but not before
the internal Address Pointer is set. The host then
issues the control byte again, but with the R/W bit set
to a ‘1’. The 24XX64 will then issue an Acknowledge
and transmit the 8-bit data word. The host will not
acknowledge the transfer, but does generate a Stop
condition, which causes the 24XX64 to discontinue
transmission (Figure 8-2). After a random Read
command, the internal Address Pointer will point to
the address location following the one that was just
read.
8.3
Sequential Read
Sequential reads are initiated in the same way as
random reads, except that once the 24XX64 transmits
the first data byte, the host issues an Acknowledge as
opposed to the Stop condition used in a random read.
This Acknowledge directs the 24XX64 to transmit the
next sequentially-addressed 8-bit word (Figure 8-3).
Following the final byte being transmitted to the host,
the host will NOT generate an Acknowledge, but will
generate a Stop condition. To provide sequential reads,
the 24XX64 contains an internal Address Pointer which
is incremented by one at the completion of each
operation. This Address Pointer allows the entire
memory contents to be serially read during one
operation. The internal Address Pointer will
automatically roll over from address 1FFF to address
0000 if the host acknowledges the byte received from
the array address 1FFF.
CURRENT ADDRESS READ
Bus Activity
Host
S
T
A
R
T
Control
Byte
SDA Line
S
A
1 0 1 0 A2 A
1 0 1
Bus Activity
1997-2022 Microchip Technology Inc. and its subsidiaries
S
T
O
P
Data Byte
P
A
C
K
N
O
A
C
K
DS20001189U-page 13
24AA64/24FC64/24LC64
FIGURE 8-2:
Bus Activity
Host
SDA Line
RANDOM READ
S
T
A
R
T
Control
Byte
Address
High Byte
S1 010AAA0
2 1 0
xxx
A
C
K
A
C
K
Bus Activity
S
T
A
R
T
Address
Low Byte
A
C
K
Control
Byte
S 1 0 1 0 A AA1
2 10
S
T
O
P
Data
Byte
P
N
O
A
C
K
A
C
K
x = “don’t care” bit
FIGURE 8-3:
Bus Activity
Host
SEQUENTIAL READ
Control
Byte
Data n
Data n + 1
Data n + 2
S
T
O
P
Data n + x
P
SDA Line
Bus Activity
DS20001189U-page 14
A
C
K
A
C
K
A
C
K
A
C
K
N
O
A
C
K
1997-2022 Microchip Technology Inc. and its subsidiaries
24AA64/24FC64/24LC64
9.0
PACKAGING INFORMATION
9.1
Package Marking Information
5-Lead Chip Scale
XW
NN
8-Lead 2x3 DFN
XXX
YWW
NN
8-Lead 5x6 DFN-S
Example
72
13
Example
274
204
13
Example
24FC64
I/MF e3
2204
13F
8-Lead MSOP
Example
XXXXXT
4L64I
YWWNNN
20413F
8-Lead PDIP (300 mil)
Example
XXXXXXXX
T/XXXNNN
YYWW
24LC64
I/P e3 13F
2204
8-Lead SOIC
Example
XXXXXXXT
XXXXYYWW
NNN
24LC64I
SN e3 2204
13F
8-Lead SOIJ
Example
XXXXXXXX
T/XXXXXX
YYWWNNN
24LC64
I/SM e3
220413F
1997-2022 Microchip Technology Inc. and its subsidiaries
DS20001189U-page 15
24AA64/24FC64/24LC64
5-Lead SOT-23
Example
XXNN
7GNN
8-Lead 2x3 TDFN
Example
XXX
YWW
NN
A74
527
I3
Example
8-Lead TSSOP
XXXX
4LB
TYWW
I204
NNN
13F
1st Line Marking Codes
Part
Number
DFN
MSOP
SOT-23
TDFN
TSSOP
I-Temp.
E-Temp.
I-Temp.
E-Temp.
I-Temp.
E-Temp.
Standard
Rotated
24AA64
271
—
4A64T(1)
7HNN(2)
7WNN(2)
A71
E10
4AB
4ABX
24FC64
27A
—
4F64T(1)
7SNN(2)
—
A7A
—
4FB
—
275
4L64T(1)
7GNN(2)
7JNN(2)
A74
A75
4LB
4LBX
24LC64
Note 1:
2:
274
T = Temperature grade (I, E)
NN = Alphanumeric traceability code
Legend: XX...X
T
Y
YY
WW
NNN
e3
Part number or part number code
Temperature (I, E)
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code (2 characters for small packages)
JEDEC® designator for Matte Tin (Sn)
* Standard OTP marking consists of Microchip part number, year code, week code and
traceability code.
Note:
For very small packages with no room for the JEDEC® designator
e3 , the marking will only appear on the outer carton or reel label.
Note:
In the event the full Microchip part number cannot be marked on one line, it
will be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
DS20001189U-page 16
1997-2022 Microchip Technology Inc. and its subsidiaries
24AA64/24FC64/24LC64
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
1997-2022 Microchip Technology Inc. and its subsidiaries
DS20001189U-page 17
24AA64/24FC64/24LC64
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
DS20001189U-page 18
1997-2022 Microchip Technology Inc. and its subsidiaries
24AA64/24FC64/24LC64
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
1997-2022 Microchip Technology Inc. and its subsidiaries
DS20001189U-page 19
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DS20001189U-page 43
24AA64/24FC64/24LC64
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