DESCRIPTION
The members of the ST1335D/36D/55D 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 (ST1335D/55D)
■ Cipher Block Chaining Function (ST1355D)
■ 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 (ST1336D) or Authentication Secret Key (ST1335D/55D)
   – 32 bits of Anti-tearing Flags (optional)
   – 56 bits of User data (optionally not erasable)
■ More than 500,000 Erase/Write Cycles
■ More than 10 Years Data Retention
■ 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)