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34AA02 Schematic ( PDF Datasheet ) - Microchip Technology

Teilenummer 34AA02
Beschreibung 2K I2C Serial EEPROM Software Write-Protect
Hersteller Microchip Technology
Logo Microchip Technology Logo 




Gesamt 30 Seiten
34AA02 Datasheet, Funktion
34AA02/34LC02
2K I2CSerial EEPROM Software Write-Protect
Features:
• Permanent and Resettable Software Write-Protect
for Lower Half of the Array (00h-7Fh)
• Single Supply with Operation Down to 1.7V
• Low-Power CMOS Technology:
- Read current 1 mA, typical
- Standby current, 100 nA, typical
• 2-Wire Serial Interface Bus, I2C™ Compatible
• Cascadable up to Eight Devices
• Schmitt Trigger Inputs for Noise Suppression
• Output Slope Control to Eliminate Ground Bounce
• 100 kHz and 400 kHz Compatibility
• 1 MHz Clock for LC Versions
• Page Write Time 3 ms, typical
• Self-Timed Erase/Write Cycle
• 16-Byte Page Write Buffer
• ESD Protection > 4,000V
• Software Write Protection for Lower 128 Bytes
• Hardware Write Protection for Entire Array
• More than 1 Million Erase/Write Cycles
• Data Retention > 200 Years
• 8-Lead PDIP, SOIC, TSSOP, MSOP and TDFN
Packages
• 6-Lead SOT-23 Package
• Pb-free and RoHS Compliant
• Available for Extended Temperature Ranges:
- Industrial (I): -40°C to +85°C
- Automotive (E): -40°C to +125°C
Device Selection Table
Part
Number
VCC
Range
Max. Clock
Frequency
34AA02
34LC02
1.7-5.5
2.2-5.5
400 kHz(1)
1 MHz
Note 1: 100 kHz for VCC <1.8V.
Temp
Ranges
I,E
I,E
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Package Types
PDIP/SOIC/TSSOP/MSOP/TDFN
A0 1
A1 2
A2 3
VSS 4
8 VCC
7 WP
6 SCL
5 SDA
A0 1
A1 2
A2 3
VSS 4
8 VCC
7 WP
6 SCL
5 SDA
SOT-23
SCL 1
VSS 2
SDA 3
6 VCC
5 A0
4 A1
Description:
The Microchip Technology Inc. 34AA02/34LC02
(34XX02*) is a 2 Kbit Electrically Erasable PROM
capable of operation across a broad voltage range
(1.7V to 5.5V). This device has two software write-
protect features for the lower half of the array, as well
as an external pin that can be used to write-protect the
entire array. This allows the system designer to protect
none, half, or all of the array, depending on the
application. The device is organized as one block of
256 x 8-bit memory with a 2-wire serial interface. Low-
voltage design permits operation down to 1.7V, with
standby and active currents of only 100 nA and 1 mA,
respectively. The 34XX02 also has a page write
capability for up to 16 bytes of data. The 34XX02 is
available in the standard 8-pin PDIP, surface mount
SOIC, TSSOP, MSOP and TDFN packages. The
34XX02 is also available in the 6-lead, SOT-23
package.
*34XX02 is used in this document as a generic part number
for the 34AA02/34LC02 devices.
2011 Microchip Technology Inc.
DS22029F-page 1






34AA02 Datasheet, Funktion
34AA02/34LC02
2.0 FUNCTIONAL DESCRIPTION
The 34XX02 has two Software Write-Protect features
that allow you to protect half of the array from being
written (Addresses 00h-7Fh). One command, Software
Write-Protect (SWP) will prevent writes to half of the
array and is resettable by using the Clear Software
Write-Protect (CSWP) command. The other command
is Permanent Software Write-Protect (PSWP), which is
not resettable and will permanently lock half the array
from being written to. The device still has an external
pin (WP) that allows you to protect the entire array if so
desired.
The 34XX02 supports a bidirectional 2-wire bus and
data transmission protocol. A device that sends data
onto the bus is defined as a transmitter, and a device
receiving data, as a receiver. The bus has to be
controlled by a master device, which generates the
Serial Clock (SCL), controls the bus access and gener-
ates the Start and Stop conditions, while the 34XX02
works as slave. Both master and slave can operate as
transmitter or receiver, but the master device
determines which mode is activated.
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).
3.1 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 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.
www.Da3ta.4Sheet4UD.acotamValid (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.
DS22029F-page 6
Each data transfer is initiated with a Start condition and
terminated with a Stop condition. The number of data
bytes transferred between the 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.
3.5 Acknowledge
Each receiving device, when addressed, is obliged to
generate an Acknowledge after the reception of each
byte. Exceptions to this rule relating to software write
protection are described in Section 7.0 “Write Protec-
tion”. The master device must generate an extra clock
pulse, which is associated with this Acknowledge bit.
Note:
The 34XX02 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. Of
course, setup and hold times must be taken into
account. During 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 (34XX02) will leave the data line
high to enable the master to generate the Stop
condition.
2011 Microchip Technology Inc.

6 Page









34AA02 pdf, datenblatt
34AA02/34LC02
7.0 WRITE PROTECTION
The 34XX02 has two software write-protect features
(SWP and PSWP) that allows the lower half of the array
(addresses 00h-7Fh) to be write-protected, as well as
a WP pin that can be used to protect the entire array.
The permanent software write-protect feature is
enabled by sending the device a special command.
Once this feature has been enabled, it cannot be
reversed. The resettable software write-protect feature
is also enabled by sending the device a special
command but can be reset by issuing another special
command. In addition to the software protect features,
there is a WP pin that can be used to write-protect the
entire array, regardless of whether the software write-
protect register has been written or not.
Table 7-2 and Table 7-3 describe how the 34XX02 will
acknowledge specific commands under various
circumstances.
7.1 Hardware Write Protection
The WP pin allows the user to write-protect the entire
array (00-FF) when the pin is tied to VCC. If the pin is
tied to VSS the write protection is disabled.
7.2 Software Write Protection (SWP)
and Clear Software Write
Protection (CSWP)
In addition to hardware write-protect the 34XX02 has
an additional software write-protect feature that, when
set, protects the first 128 bytes (00-7Fh) of the array
from being written.
Setting the software write protection is done by sending
the SWP instruction. SWP can also then be cleared by
issuing a CSWP instruction (see Figure 7-1).
These two instructions follow the same format as the
BYTE WRITE instruction with the exception of the
Device Type Identifier, (typically ‘1010’, instead
changes to ‘0110’). Once this identifier is recognized
by the device, the rest of the Byte Write command,
address and data, are “don’t cares”. In addition to the
identifier, high voltage must be applied to the A0 pin of
the device and specific levels must be present on A1
and A2. See Table 7-1 for the available commands.
7.3 Permanent Software Write-Protect
(PSWP)
The Permanent software write protection, or PSWP is
another instruction that may be used to permanently
protect the first 128 byte of the array. Once this
command is issued, the user will no longer have the
ability to clear this feature regardless of instruction,
power cycling, or state of the WP pin. Also, once this
instruction has been executed, the device will no
longer acknowledge the device identifier ‘0110’.
FIGURE 7-1:
SOFTWARE WRITE PROTECTION FOR SWP, CSWP, PSWP, OR CPSWP
Bus Activity
Master
SDA Line
Bus Activity
S
T
A
R
Control
Byte
T
S
0
1
1
0
A
2
A
1
A
0
0
A
C
K
Address
Byte
“Don’t Care”
A
C
K
Data
S
T
O
P
P
A
“Don’t Care” C
K
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DS22029F-page 12
2011 Microchip Technology Inc.

12 Page





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