Dual SIM/Smart card power supply for 3G
April 16, 2004
Linear Technology announces the LTC4557, a dual SIM/Smart card power supply and level translator, which provides both 1.8V and 3V SIM power and digital signal level shifting from a 3 x 3mm QFN package. It provides power and level shifting for 2.5G/3G wireless applications which are required to interface with either a 1.8V or 3V SIM or Smart Card. The LTC4557 can withstand >10kV ESD on all of the SIM contact pins and meets all ETSI, EMV and ISO7816 SIM/Smart card approval requirements. Its tiny 16 lead QFN package has only a 0.75mm profile, making it ideal for space-constrained applications.
The LTC4557 contains an LDO regulator to supply SIM power at either 1.8V or 3V from a 3V to 6V input. The SIM/Smart card voltage is selected by the baseband controller via a single pin (each channel), enabling the device to deliver up to 50mA of load current. Internal level translators allow controllers operating with supply voltages from 1.2V to 4.4V to interface with 1.8V or 3V SIM cards. Finally, a very low operating current of 100uA (<1ľA in shut down) ensures optimal battery life. The combination of a very small solution footprint and low supply current make it ideal for battery-powered wireless applications.
LTC4557EUD is available from stock in a 16-Lead QFN package, 1,000-piece pricing starts at $2.50 each.
Summary of Features: LTC4557
-- Power Management & Signal Level Translators for Two SIM Cards or Smart Cards
-- Independent 1.8V/3V VCC Control for Each Card
-- Automatic Level Translation
-- ISO7816, ETSI & EMV Compliant
-- Built-In Fault Protection Circuitry
-- Automatic Activation/Deactivation Sequencing Circuitry
-- Quiescent Current: 100ľA, ISD, 1ľA
-- >10kV ESD on SIM Card Pins
-- Available in 16-Lead (3mm x 3mm) QFN Package
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