The e5530 is part of a closed coupled identification system. It receives power from an RF transmitter which is coupled inductively to the IDIC. The frequency is typically 100 kHz to 450 kHz. Receiving RF, the IDIC r esponds with a data stream by damping the incoming RF via an internal load. This damping-in-turn can be detected by the interrogator. The identifying data are stored in a 128-bit PROM on the e5530, realized as an array of laser-programmable fuses. The logic block diagram for the e5530 is shown in figure 2. The data are output bit-serially as a code of length 128, 96, 64 or 32 bits. The chips are factory-programmed with a unique code.