EEPROM & RAM
I2C Serial EEPROM and RAM
I2C Slave Address
1
0
1
0
FIXED
A2
A1
A0
or
or
or
R/W
Block# Block# Block#
PROGRAMMABLE
PCA8581/8581(C)
PCF8570/82/94/98/102/116
Semiconductors
0
0
1
FIXED
0
A2
A1
A0
R/W
PROGRAMMABLE
PCF85103
Description
The Philips family of I2C bus compatible memories comprises RAM,
EEPROM, video memories and Flash memories.
Small size serial memories (RAM and EEPROM) are fairly common and
widely used in many different applications. EEPROM is particularly useful
in applications where data retention during power-off is essential. Such
applications include but are not limited to: meter readings, electronic key,
product identification number, serial presence detect (SPD) on DIMMs, etc.
A common pinning is used for these serial memories because their functionality is very similar.The common pinout was selected to allow interchangeability. EEPROMs store data (2 Kbits organized in 256 X 8 in the
PCF8582C-2 for example), including set points, temperature, alarms, DIMM
information and more, for a guaranteed minimum storage time of ten years
in the absence of power. EEPROMs can change values up to 1,000,000 times
and have an infinite number of read cycles, while consuming only 10 micro
Amperes of current.
RAM—Random Access Memory
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The PCF8570 is organized as 256 words of 8-bytes.
EEPROM—EEPROM is Electrically Erasable Programmable Read
Only Memory
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The PCF8581/8581C is organized as 128 words of 8-bytes.
The PCF8582C-2 is organized as 256 words of 8-bytes.
The PCF8594C-2 is organized as 512 words of 8-bytes in two
256 word pages.
The PCF8598C-2 is organized as 1024 words of 8-bytes in four
256 word pages.
The PCF85116-3 is organized as 2048 words of 8-bytes in eight
256 word pages.
The PCF8582C-2 is pin and address compatible with the PCF8570 and
PCA8581.The PCF85102C-2 is identical to the PCF8582C-2, with pin 7
(Programming Time Control output) as a no connect, to allow it to be used
in competitors’ sockets, since PTC should be left floating or held at VCC.
The PCF85103C-2 is identical to the PCF8582C-2 except that the fixed I2C
address is different, allowing up to eight of each device to be used on the
same I2C bus.
Addresses and data are transferred serially via a two-wire bi-directional bus
(I2C-bus).The built-in word address register is incremented automatically
after each written or read data byte.All bytes can be read in a single operation. Up to 8 bytes can be written in one operation, reducing the total write
time per byte.
The 512-byte, 1024-byte and 2048-byte EEPROMs use the programmable
address (Ax or Block #) to either select the slave address or one of the
256 word pages (e.g., the PCF8594C-2 has two addressable pages with up
to four devices allowed on the same I2C bus while the PCF85116-3 has
eight addressable pages but only one device is allowed on the same I2C bus).
EEPROM/RAM Features
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Wide voltage range of 2.5 V to 5.5V
Internal non-volatile registers (except PCF8570) with a minimum of
1,000,000 write cycles at Tambient = 22 ºC
Infinite number of read cycles
10 year data retention (Minimum)
Low power CMOS devices
Non volatile storage from 128x8-bit to 2048x8-bit
Write operation per byte or per 8-byte page
Read operation can be sequential or random
Internal timer for writing operation (no external components required)
Internal Power On Reset
High reliability by using redundant EEPROMS cells
Offered in 8-pin DIP (N) and SO (D) packages
Key Points
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The I2C bus is used to read and write information to and from the
memory
A wide voltage range minimizes the number of EEPROMs that need to
be stocked