The EM4033 from EM Microelectronic is a RFID Tag IC with Capacitance 23.5 pF, Frequency 13.56 MHz, Operating Temperature -40 to 85 Degree C, Storage Temperature -55 to 125 Degree C, Voltage -0.3 to 7 V. Tags: Passive. More details for EM4033 can be seen below.