DESCRIPTION
The members of the ST1335/1336/1355 family are principally designed for use in prepaid Phonecard applications. Each is a 272-bit EEPROM device, with associated security logic and special fuses to control memory access. The memory is arranged as a matrix of 34 x 8 cells, accessed in a serial bit wise fashion for reading and programming, and in a byte-wise fashion for internal erasing.

■ 5 V Single Supply Voltage
■ Counting Capability (two options)
  – up to 32767 (85 -1)
  – 8 times reloadable, up to 4095 (84-1)
■ Active Authentication Function (ST1335/1355)
■ Cipher Block Chaining Function (ST1355)
■ Memory Divided into :
  – 16 bits of Circuit Identification
  – 48 bits of Card Identification
  – 40 bits of Count Data
  – 16 bits for Validation Certificate
  – 24 bits of Transport Code
  – 64 bits of Issuer Data (ST1336) or Authentication Secret Key (ST1335/1355)
  – 32 bits of Anti-tearing Flags (optional)
  – 56 bits of User data (optionally not erasable)
■ 1 Million Erase/Write Cycle (minimum)
■ 10 Year Data Retention (minimum)
■ 3.5 ms Programming Time at 5 V (typical)
■ 500 µA Supply Current at 5 V (typical)
■ 250 µA Stand-by Current at 5 V (typical)