Features

• 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

Typical Application

Description

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