DESIGN FEATURES LTC1755 Smart Card Interface
Provides Inductorless Boost
and Signal-Level Translators by Steven Martin
Introduction
Already common in Europe and some
of the Far East, smart cards may soon
replace magnetic stripe cards in the
U.S. The LTC1755 provides a simple
and complete solution to smart card
interfacing. Requiring only two bypass
capacitors and one charge pump
capacitor, the LTC1755 interfaces
seamlessly between a smart card
socket and a host microcontroller. It
is designed to comply with all of the
available electrical standards for
smart card interfacing. Figure 1 shows
the LTC1755 in a typical smart card
application.
Figure 2 shows the block diagram
of the LTC1755. An internal power
management unit delivers a selectable 3V or 5V regulated output voltage
to the smart card. Two unidirectional …