The LTC4558 contains an LDO regulator to supply SIM power at either 1.8V or 3V from a 2.7V to 5.5V input. The SIM/Smart card voltages are selected via a single pin per channel, and up to 50mA of load current may be delivered. Patented dynamic pull-ups deliver fast rise times. Internal level translators accommodate a wide input range for controllers operating with supply voltages from 1.4V to 5.5V to interface with 1.8V or 3V SIM Cards. A very low operating current of 65uA (<1uA in shut down) ensures optimal battery run time. The combination of a very small solution footprint and low supply current make the LTC4558 ideal for battery-powered wireless applications.
Dual SIM/Smart Card Power Supply IC
Linear Technology has announced the LTC4558, a dual subscriber identity module (SIM) and Smart Card power supply IC with level translator that provides both 1.8V and 3V SIM power and digital signal level shifting in a tiny QFN package. The LTC4558 is ideal for GSM, TD-SCDMA and other 3G+ wireless applications that interface with either a 1.8V or 3V SIM or Smart Card. A channel select pin determines which channel is open for communication, while separate enable pins allow both cards to be powered at once and provide fast transition from one channel to the other. The LTC4558 can withstand >10kV ESD on all of the SIM contact pins and is designed to meet all ETSI, EMV and ISO7816 SIM/Smart card approval requirements. Its tiny 20-lead QFN package has only a 0.75mm profile, making it ideal for space-constrained applications.