Obsolete Device
Please use 24LC32A or 24LC65.
24LC32
32K 2.5V I
2
C
™
Smart Serial EEPROM
FEATURES
• Voltage operating range: 2.5V to 6.0V
- Peak write current 3 mA at 6.0V
- Maximum read current 150
µA
at 6.0V
- Standby current 1
µA
typical
• Industry standard two-wire bus protocol, I
2
C
compatible
- Including 100 kHz (2.5V) and 400 kHz (5V) modes
• Self-timed ERASE and WRITE cycles
• Power on/off data protection circuitry
• Endurance:
- 10,000,000 Erase/Write cycles
guaranteed for High Endurance Block
- 1,000,000 E/W cycles guaranteed for
Standard Endurance Block
• 8 byte page, or byte modes available
• 1 page x 8 line input cache (64 bytes) for fast write
loads
• Schmitt trigger, filtered inputs for noise suppression
• Output slope control to eliminate ground bounce
• 2 ms typical write cycle time, byte or page
• Factory programming (QTP) available
• Up to 8 devices may be connected to the same
bus for up to 256K bits total memory
• Electrostatic discharge protection > 4000V
• Data retention > 200 years
• 8-pin PDIP/SOIC packages
• Temperature ranges
- Commercial (C):
0°C to +70°C
- Industrial (I):
-40° to +85°
PACKAGE TYPES
PDIP
A0
A1
A2
V
SS
1
2
3
4
24LC32
8
7
6
5
V
CC
NC
SCL
SDA
SOIC
1
2
3
4
24LC32
A0
A1
A2
V
SS
8
7
6
5
V
CC
NC
SCL
SDA
BLOCK DIAGRAM
A0 A1 A2
HV GENERATOR
DESCRIPTION
The Microchip Technology Inc. 24LC32 is a 4K x 8
(32K bit) Serial Electrically Erasable PROM capable of
operation across a broad voltage range (2.5V to 6.0V).
This device has been developed for advanced, low
power applications such as personal communications
or data acquisition. The 24LC32 features an input
cache for fast write loads with a capacity of eight 8-byte
pages, or 64 bytes. It also features a fixed 4K-bit block
of ultra-high endurance memory for data that changes
frequently. The 24LC32 is capable of both random and
sequential reads up to the 32K boundary. Functional
address lines allow up to eight 24LC32 devices on the
same bus, for up to 256K bits address space.
Advanced CMOS technology and broad voltage range
make this device ideal for low-power/low voltage, non-
volatile code and data applications. The 24LC32 is
available the standard 8-pin in plastic DIP and 8-pin
surface mount SOIC package.
I/O
CONTROL
LOGIC
MEMORY
CONTROL
LOGIC
XDEC
EEPROM
ARRAY
PAGE LATCHES
I/O
SCL
CACHE
SDA
V
CC
V
SS
YDEC
SENSE AMP
R/W CONTROL
I
2
C is a trademark of Philips Corporation. Smart Serial is a trademark of Microchip Technology Inc.
2004 Microchip Technology Inc.
DS21072G-page 1
24LC32
1.0
1.1
ELECTRICAL
CHARACTERISTICS
Maximum Ratings*
TABLE 1-1:
Name
A0,A1,A2
V
SS
SDA
SCL
V
CC
NC
PIN FUNCTION TABLE
Function
User Configurable Chip Selects
Ground
Serial Address/Data I/O
Serial Clock
+2.5V to 6.0V Power Supply
No Internal Connection
V
CC
..................................................................................7.0V
All inputs and outputs w.r.t. V
SS
............... -0.6V to V
CC
+1.0V
Storage temperature .....................................-65°C to +150°C
Ambient temp. with power applied ................-65°C to +125°C
Soldering temperature of leads (10 seconds) ............. +300°C
ESD protection on all pins
..................................................≥
4 kV
*Notice:
Stresses above those listed under “Maximum Ratings”
may cause permanent damage to the device. This is a stress rat-
ing 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 1-2:
DC CHARACTERISTICS
V
CC
= +2.5V to 6.0V
Commercial (C):
Tamb
Industrial (I):
Tamb
Parameter
Symbol
Min
Max
Units
= 0°C to +70°C
= -40°C to +85°C
Conditions
A0, A1, A2, SCL and SDA pins:
High level input voltage
Low level input voltage
Hysteresis of Schmitt Trigger inputs
Low level output voltage
Input leakage current
Output leakage current
Pin capacitance
(all inputs/outputs)
Operating current
Standby current
Note:
V
IH
V
IL
V
HYS
V
OL
I
LI
I
LO
C
IN
,
C
OUT
I
CC
Write
I
CC
Read
I
CCS
.7 V
CC
—
.05 V
CC
—
-10
-10
—
—
—
—
—
.3 Vcc
—
.40
10
10
10
3
150
5
V
V
V
V
µA
µA
pF
mA
µA
µA
(Note)
I
OL
= 3.0 mA
V
IN
= .1V to V
CC
V
OUT
= .1V to V
CC
V
CC
= 5.0V (Note)
Tamb = 25°C, Fclk = 1 MHz
V
CC
= 6.0V, SCL = 400 kHz
V
CC
= 6.0V, SCL = 400 kHz
V
CC
= 5.0V, SCL = SDA = V
CC
A0, A1, A2 = V
SS
This parameter is periodically sampled and not 100% tested.
FIGURE 1-1:
BUS TIMING START/STOP
V
HYS
SCL
T
SU
:
STA
SDA
T
HD
:
STA
T
SU
:
STO
START
STOP
DS21072G-page 2
2004 Microchip Technology Inc.
24LC32
TABLE 1-3:
AC CHARACTERISTICS
V
CC
= 2.5V-6.0V V
CC
= 4.5 - 6.0V
STD. MODE
FAST MODE
Min
Clock frequency
Clock high time
Clock low time
SDA and SCL rise time
SDA and SCL fall time
START condition hold time
START condition setup time
Data input hold time
Data input setup time
STOP condition setup time
Output valid from clock
Bus free time
F
CLK
T
HIGH
T
LOW
T
R
T
F
T
HD
:
STA
T
SU
:
STA
T
HD
:
DAT
T
SU
:
DAT
T
SU
:
STO
T
AA
T
BUF
—
4000
4700
—
—
4000
4700
0
250
4000
—
4700
Parameter
Symbol
Units
kHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Remarks
Max
100
—
—
1000
300
—
—
—
—
—
3500
—
Min
—
600
1300
—
—
600
600
0
100
600
—
1300
Max
400
—
—
300
300
—
—
—
—
—
900
—
(Note1)
(Note1)
After this period the first clock
pulse is generated
Only relevant for repeated
START condition
Output fall time from V
IH
min
to V
IL
max
Input filter spike suppression
(SDA and SCL pins)
Write cycle time
Endurance
High Endurance Block
Rest of Array
T
OF
T
SP
T
WR
—
—
—
—
—
10M
1M
250
50
5
—
—
20 +0.1
C
B
—
—
10M
1M
250
50
5
—
—
ns
ns
(Note 2)
Time the bus must be free
before a new transmission can
start
(Note 1), C
B
≤
100 pF
(Note 3)
ms/page (Note 4)
cycles
25°C, Vcc = 5.0V, Block Mode
(Note 5)
Note 1: Not 100% tested. C
B
= total capacitance of one bus line in pF.
2: 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.
3: The combined T
SP
and V
HYS
specifications are due to new Schmitt trigger inputs which provide improved
noise and spike suppression. This eliminates the need for a Ti specification for standard operation.
4: The times shown are for a single page of 8 bytes. Multiply by the number of pages loaded into the write
cache for total time.
5: This parameter is not tested but guaranteed by characterization. For endurance estimates in a specific appli-
cation, please consult the Total Endurance Model which can be obtained from our website.
FIGURE 1-2:
BUS TIMING DATA
T
F
T
HIGH
T
LOW
SCL
T
SU
:
STA
T
HD
:
STA
SDA
IN
T
SP
T
AA
SDA
OUT
T
AA
T
HD
:
DAT
T
SU
:
DAT
T
SU
:
STO
T
R
T
BUF
2004 Microchip Technology Inc.
DS21072G-page 3
24LC32
2.0
FUNCTIONAL DESCRIPTION
3.4
Data Valid (D)
The 24LC32 supports a bidirectional two-wire bus and
data transmission protocol. A device that sends data
onto the bus is defined as transmitter, and a device
receiving data as receiver. The bus must be controlled
by a master device which generates the serial clock
(SCL), controls the bus access, and generates the
START and STOP conditions, while the 24LC32 works
as slave. Both master and slave can operate as trans-
mitter or receiver but the master device determines
which mode is activated.
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
the data bytes transferred between the START and
STOP conditions is determined by the master device.
3.0
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 3-1).
3.5
Acknowledge
Each receiving device, when addressed, is obliged to
generate an acknowledge signal after the reception of
each byte. The master device must generate an extra
clock pulse which is associated with this acknowledge
bit.
Note:
The 24LC32 does not generate any
acknowledge bits if an internal program-
ming cycle is in progress.
3.1
Bus not Busy (A)
Both data and clock lines remain HIGH.
3.2
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 condi-
tion.
A device that acknowledges must 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. Of course,
setup and hold times must be taken into account. Dur-
ing reads, a master must signal an end of data to the
slave by NOT generating an acknowledge bit on the
last byte that has been clocked out of the slave. In this
case, the slave (24LC32) will leave the data line HIGH
to enable the master to generate the STOP condition.
3.3
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 3-1:
DATA TRANSFER SEQUENCE ON THE SERIAL BUS
SCL
(A)
(B)
(D)
(D)
(C)
(A)
SDA
START
CONDITION
ADDRESS OR
ACKNOWLEDGE
VALID
DATA
ALLOWED
TO CHANGE
STOP
CONDITION
DS21072G-page 4
2004 Microchip Technology Inc.
24LC32
3.6
Device Addressing
FIGURE 3-2:
A control byte is the first byte received following the
start condition from the master device. The control byte
consists of a four bit control code; for the 24LC32 this
is set as 1010 binary for read and write operations. The
next three bits of the control byte are the device select
bits (A2, A1, A0). They are used by the master device
to select which of the eight devices are to be accessed.
These bits are in effect the three most significant bits of
the word address. The last bit of the control byte
defines the operation to be performed. When set to a
one a read operation is selected, and when set to a
zero a write operation is selected. The next two bytes
received define the address of the first data byte
(Figure 3-3). Because only A11...A0 are used, the
upper four address bits must be zeros. The most signif-
icant bit of the most significant byte of the address is
transferred first.
Following the start condition, the 24LC32 monitors the
SDA bus checking the device type identifier being
transmitted. Upon receiving a 1010 code and appropri-
ate device select bits, the slave device outputs an
acknowledge signal on the SDA line. Depending on
the state of the R/W bit, the 24LC32 will select a read
or write operation.
CONTROL BYTE
ALLOCATION
READ/WRITE
START
SLAVE ADDRESS
R/W
A
1
0
1
0
A2
A1
A0
Operation
Read
Write
Control
Code
1010
1010
Device Select
Device Address
Device Address
R/W
1
0
FIGURE 3-3:
ADDRESS SEQUENCE BIT ASSIGNMENTS
ADDRESS BYTE 1
A
0 R/W
A
11
A
10
A
9
A
8
A
7
CONTROL BYTE
A
2
A
1
ADDRESS BYTE 0
•
•
•
•
•
•
A
0
1
0
1
0
0
0
0
0
SLAVE
ADDRESS
DEVICE
SELECT
BUS
2004 Microchip Technology Inc.
DS21072G-page 5
PCB Design
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