The NXT4556 device is built for interfacing a SIM card with a single low-voltage host side interface. The NXT4556 has three level translators to convert the data, RST and CLK signals between a SIM card and a host microcontroller. A high speed level translation capable of supporting class-B, class-C SIM cards. VCCSIM power-down initiates a shutdown sequence on SIM card pins in accordance with ISO-7816-3. The NXT4556 is compliant with all ETSI, IMT-2000 and ISO-7816 SIM/Smart card interface requirements.