Contactless Reprogrammable Nonvolatile Memory Storage And Transmission

A variety of applications require the use of a reprogrammable nonvolatile memory that can receive and transmit data without physical contact. Such applications include: debitlcredit cards, ticketdpasses, identification tags for cargo or personnel. These applications have in common the need to send and receive data without physical contact, to retain data without a power supply, and to alter the stored data in real time. Thin oxide floating gate EEPROMs fabricated on a 1.5 p BiCMOS process provide these functions. Two RF (radio frequency) coils are used to receive power and data from the transmitter and to send data to the receiver, i.e., up to 2 feet of separation. Single chip or two chip solutions are available, depending on the memory density required, e.g., up to 16K bits. EEPROM control fuses are used to optimize demodulation sensitivity and carrier frequency ranges. Data can be transferred at up to 19.2k baud using a serial format consisting of a start bit, 8 data bits, a parity bit, and a stop bit. This paper will describe the design techniques used to implement these features. Details will be provided for the operating specifications of such devices.