NVT4556 device is "Not recommended for new designs", please use the replacement part NVT4557.
The NVT4556 device is built for interfacing a SIM card with a single low-voltage host-side
interface. The NVT4556 contains an LDO that can deliver two different voltages, 1.8 V or
3 V, from a typical mobile phone battery voltage, and three level translators to convert the
data, RSTn and CLKn signals between a SIM card and a host microcontroller.
The NVT4556 VCC pin provides power to the host side I/Os and doubles as an enable pin,
for this reason it can be connected to a GPIO that matches the host side voltage. The total
current draw from the VCC pin is only 100 μA maximum. The NVT4556 also uses the
I²C-bus interface to enable normal operation and to select either 1.8 V or 3 V for the SIM
card power supply. The NVT4556 can also disable the LDO functionality while maintaining
the level translator paths so that the user can use a system-controlled regulator to power
the SIM card power supply. The NVT4556 can enable users to provide second and third
SIM card functionality with a low-voltage one host SIM port, at the same time reducing the
number of GPIOs used in the system. The NVT4556 is compliant with all ETSI, IMT-2000
and ISO-7816 SIM/Smart card interface requirements.
The NVT4556 is available in a 12-pin WLCSP package and has three factory
programmed address options.