1661B–SEEPR–04/04
Two-wire Serial
EEPROM Smart
Card Modules
128K (16,384 x 8)
256 (32,768 x 8)
AT24C128SC
AT24C256SC
Features
Low-voltage and Standard-voltage Operation, V
CC
= 2.7V to 5.5V
Internally Organized 16,384 x 8 and 32,768 x 8
2-wire Serial Interface
Schmitt Trigger, Filtered Inputs for Noise Suppression
Bi-directional Data Transfer Protocol
1 MHz (5V) and 400 kHz (2.7V) Compatibility
64-byte Page Write Mode (Partial Page Writes Allowed)
Self-timed Write Cycle (5 ms Typical)
High Reliability
– Endurance: 1 Million Write Cycles
– Data Retention: 40 Years
– ESD Protection: > 4000V
Description
The AT24C128SC/256SC provides 131,072/262,144 bits of serial electrically erasable
and programmable read only memory (EEPROM) organized as 16,384/32,768 words
of 8 bits each. The devices are optimized for use in smart card applications where low-
power and low-voltage operation may be essential. The devices are available in sev-
eral standard ISO 7816 smart card modules (see Ordering Information). All devices
are functionally equivalent to Atmel Serial EEPROM products offered in standard IC
packages (PDIP, SOIC, TSSOP, dBGA), with the exception of the slave address and
Write Protect functions which are not required for smart card applications.
Table 1. Pin Configurations
Figure 1. Card Module Contact
Pad Name Description ISO Module Contact
VCC Power Supply Voltage C1
GND Ground C5
SCL Serial Clock Input C3
SDA Serial Data Input/Output C7
NC No Connect C2, C4, C6, C8
VCC
NC
1