A 2-Kb One-Time Programmable Memory for UHF Passive RFID Tag IC in a Standard 0.18 μm CMOS Process

We present a 2-Kb one-time programmable (OTP) memory for UHF RFID applications. The OTP memory cell is based on a two-transistor (2-T) gate-oxide anti-fuse (AF) for low voltage operation. Reliability of memory cell is enhanced by limiting the maximum terminal voltages of thin-oxide and thick-oxide transistors to 1.8 V and 3.3 V, respectively. Improved low power circuit design techniques are used including auto shut-off for program mode and self-timed control for read mode. To further reduce power consumption, we develop a novel power-efficient charge pump. The designed OTP is successfully embedded into a UHF passive RFID tag IC that conforms to the EPCglobal Gen-2 standard. The tag chip was fabricated in a 0.18 mu m 1-poly 6-metal standard CMOS process with no additional masks. The total area of the chip including the I/Os and bonding pads is 2.3 x 1.5 mm(2) where the OTP memory area is only 0.43 x 0.31 mm(2). Our tag IC measurement shows that the read and write currents of the OTP memory are 17 mu A and 58 mu A, respectively.