• Organized as 8 blocks of 256 bytes (8 x 256 x 8)
• 2-wire serial interface bus, I
• Schmitt Trigger inputs for noise suppression
• Output slope control to eliminate ground bounce
• 100 kHz (2.5V) and 400 kHz (≥2.5V) compatibility
• Self-timed write cycle (including auto-erase)
• Page write buffer for up to 16 bytes
• Hardware write-protect for entire memory
• Can be operated as a serial ROM
• Factory programming (QTP) available
• ESD protection > 4,000V
• 1,000,000 erase/write cycles
• Data retention > 200 years
• 8-lead PDIP, SOIC, TSSOP, DFN and MSOP
packages
• 5-lead SOT-23 package
• Pb-free finish available
• Available temperature ranges:
- Industrial (I): -40°C to +85°C
- Automotive (E): -40°C to +125°C
2
C™ compatible
Description:
The Microchip Technology Inc. 24AA16/24LC16B
(24XX16*) is a 16 Kbit Electrically Erasable PROM.
The device is organized as eight blocks of 256 x 8-bit
memory with a 2-wire serial interface. Low-voltage
design permits operation down to 1.8V with standby
and active currents of only 1 μA and 1 mA,
respectively. The 24XX16 also has a page write
capability fo r up to 16 bytes of data. The 24X X16 is
available in the standard 8-pin PDIP, surface mount
SOIC, TSSOP, 2x3 DFN and MSOP packages, and is
also available in the 5-lead SOT-23 package.
Package Types
A0
A1
A2
SS
V
V
SOIC, TSSOP
1
2
3
4
1
A0
2
A1
3
A2
SS
4
DFN
8
V
CC
7
WP
6
SCL
5
SDA
CC
V
8
WP
7
SCL
6
5
SDA
PDIP, MSOP
1
A0
2
A1
3
A2
4
V
SS
SOT-23-5
15
SCL
2
Vss
3
SDA
Note:Pins A0, A1 and A2 are not used by the 24XX16 (no
internal connections).
8
VCC
7
WP
6
SCL
5
SDA
WP
4
Vcc
Block Diagram
WP
HV
Generator
I/O
Control
Logic
I/O
SCL
SDA
V
CC
*24XX16 is used in this document as a generic part
Storage temperature ...............................................................................................................................-65°C to +150°C
Ambient temperature with power applied................................................................................................-65°C to +125°C
ESD protection on all pins ......................................................................................................................................................≥ 4kV
† 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 indica ted in the opera tional li stings of this sp ecification is not i mplied. Ex posure to maximum rating
conditions for extended periods may affect device reliability.
SS ......................................................................................................... -0.3V to VCC +1.0V
(†)
TABLE 1-1:DC CHARACTERISTICS
DC CHARACTERISTICS
Param.
No.
D1V
D2—High-level input voltage0.7 V
D3VILLow-level input voltage——0.3 VCCV—
D4VHYSHysteresis of Schmitt
D5V
D6ILIInput leakage current——±1μAVIN = VSS or VCC
D7ILOOutput leakage current——±1μAVOUT = VSS or VCC
D8CIN,
D9I
D10ICC read—0.011mA—
D11ICCSStandby current—
Note 1:This parameter is periodically sampled and not 100% tested.
The 24XX16 supports a bidirectional, 2-wire bus and
data transmission protocol. A device that sends data
onto the bus is defined as a transmitter, while a device
receiving data is defined as a receiver. The bus has to
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
24XX16 works as slave. Both master and slave can
operate as transmitter or receiver, but the master
device determines which mode is activated.
3.0BUS 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 when ever the c lock lin e is high. Cha nges i n
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).
3.1Bus Not Busy (A)
Both data and clock lines remain high.
3.2Start 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.
3.3Stop Data Transfer (C)
A low-to-h i gh t ran si t io n of t h e SD A l in e whi l e t h e c lo ck
(SCL) is high determines a Stop condition. All
operations must be ended with a Stop condition.
3.4Data 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 S tart conditi on and
terminated with a Stop condition. The number of data
bytes transferred between Start and Stop conditions is
determined by the master device and is, theoretically
unlimited, (although only the last sixteen will be stored
when doing a write operation). When an overwrite does
occur it will replace data in a first-in first-out (FIFO)
fashion.
3.5Acknowledge
Each receiving device, when addressed, is obliged to
generate an acknowledge after the reception of each
byte. The ma ster devi ce m ust gener at e an ex tr a cloc k
pulse which is associated with this Acknowledge bit.
Note:The 24XX16 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 ackn owledge 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. During reads, a master must signal an end of
data to the sla ve by no t gene rating a n Ack nowl edge b it
on the last byte that has be en c loc ke d ou t of th e sl av e.
In this case, the sl ave (24 XX16) will leave the data lin e
high to enable the master to generate the Stop
condition.
FIGURE 3-1:DAT A TRANSFER SEQUENCE ON THE SERIAL BUS
A control byte is th e first byte received following the
Start condition from the master device (Figure 3-2).
The control byte consists of a four-bit control code.
For the 24XX16, this is set as ‘
and write operations. The next three bits of the control
byte are the block-sel ect bits (B2, B1, B0). T hey are
used by the master device to select which of the eight
256 word-blocks of memory are to be accessed.
These bits are in effect the thr ee Mo st S ignif ica nt bits
of the word address. It should be noted that the
protocol limits the si ze of the me mory to eight block s
of 256 wor ds , th er efore, the protocol can support only
one 24XX16 per system .
The last bit of the control byte defines the operation to
be performed. When set to ‘
selected. When set to ‘
Following the Start condition, the 24XX16 monitors the
SDA bus, checking the device type identifier being
transmitted and, upon receiving a ‘
slave device outputs an Acknowledge signal on the
SDA line. Depending on the state of the R/W bit, the
24XX16 will select a read or write operation.
Following the Start condition from the master, the
device code (4 bits), the block address (3 bits) and the
R/W bit, which is a lo gic-low, is placed onto the bus by
the master transmitter. This indicates to the addressed
slave receiver that a byte with a word address will
follow once it has generated an Ac knowledge b it during
the ninth clock cycl e. Therefore, th e next byte trans mitted by the master is the word address and will be
written into the Address Pointer of the 24XX16. After
receiving another Acknowledge signal from the
24XX16, the master device will transmit the data word
to be written into the addressed memory location. The
24XX16 acknowledges again and the master
generates a Stop condition. This initiates the internal
write cycle and, during this time, the 24XX16 will not
generate Acknowledge signals (Figure 4-1).
4.2Page Wri te
The write control byte, word address and the first data
byte are transmitted to the 24 XX16 in th e same w ay a s
in a byte write. However, instead of generating a Stop
condition, the master transmits up to 16 data bytes to
the 24XX16, which are temporarily stored in the onchip page buffer and will be written into memory once
the master has transmitted a Stop condition. Upon
receipt of each word, the four lower-order Address
Pointer bits are internally incremented by ‘
higher-order 7 bits of the word address remain
constant. If the master should transmit more than 16
bytes prior to generating the Stop condition, the
address counter will roll over and the previously
received data will be overwri tten. As w ith the by te writ e
operation, once the Stop condition is received an
internal write cycle will begin (Figure 4-2).
Note:Page write operatio ns are lim ited to wri ting
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 buf fer size (or
‘page-size’) and end a t ad dresses that a re
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 wraps around to the
beginning of the current page (overwriting
data previously stored there), instead of
being written to the next page, as might b e
expected. It is therefore necessary for the
application software to prevent page write
operations that would attempt to cross a
page boundary.
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 issu ed from the mas ter , the device
initiates the int ernally-timed wri te cycle and ACK pol ling
can then be initiated immediately. This involves the
master sending a S tart c ondition fo llowed by the contro l
byte for a Write c ommand (R/W
busy with the write cycle, no ACK will be returned. If the
cycle is complete, the device will return the ACK and
the master can then proceed with the next Read or
Write command. See Figure 5-1 for a flow diagram of
this operation.
FIGURE 5-1:ACKNOWLEDGE POLLING
FLOW
Send
Write Command
Send Stop
Condition to
Initiate Write Cycle
= 0). If the device is still
6.0WRITE-PROTECTION
The 24XX16 can be used as a serial ROM when the
WP pin is connected to V
inhibited and the entire memory will b e writ e-protected.