特点
Power Management and Signal Level Translators for Two SIM Cards or Smart Cards
Independent 1.8V/3V VCC Control for Both Cards
Automatic Level Translation
ISO7816, ETSI and EMV Compatible
Dynamic Pull-Ups Deliver Fast Signal Rise Times*
Built-In Fault Protection Circuitry
Automatic Activation/Deactivation Sequencing Circuitry
Low Operating/Shutdown Current
>10kV ESD on SIM Card Pins
Compatible with EMV Fault Tolerance Requirements
Available in 16-Lead (3mm ′ 3mm) QFN Package
典型应用
典型应用
描述
The LTC?4557 provides power conversion and signal level translation needed for 2.5G and 3G cellular telephones to interface with 1.8V or 3V subscriber identity modules (SIMs). The part meets all requirements for 1.8V and 3V SIMs. The part contains LDO regulators to power 1.8V or 3V SIM cards from a 2.7V to 5.5V input. The output voltages can be set using the two voltage selection pins and up to 50mA of load current can be supplied.
Internal level translators allow controllers operating with supplies as low as 1.2V to interface with 1.8V or 3V smart cards. Battery life is maximized by a low operating current of less than 100μA and a shutdown current of less than 1μA. Board area is minimized by the low profile 3mm x 3mm x 0.75mm leadless QFN package.
*U.S. Patent No. 6,356,140