Datasheet Linear Technology LTC1955EUH#PBF

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Design Notes

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  Single Interface Chip Controls Two Smart Cards &mdash DN289
  PDF, 95 Kb, File published: Jul 1, 2002
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  Single Interface Chip Controls Two Smart Cards – Design Note 289
  Steven Martin
  Introduction
  There are considerable challenges to smart card interfacing, including various voltage levels (both input and
  output) and stringent fault handling requirements. To
  produce a robust card reading system, designers must
  comply with extensive and often difficult software as
  well as hardware standards. Furthermore, there are
  other complications like in-circuit ESD and pin-to-pin
  shorts to contend with.
  The LTC В®1955 dual smart card interface provides all
  of the required power management, control, ESD and
  fault detection circuitry for two smart cards. Employing
  a voltage doubling charge pump and two low dropout
  linear regulators, this device generates two independent levels of either 5V, 3V or 1.8V from a 2.7V to 5.5V input. Both channels have the required pins to support
  the EMV (Europay, MasterCard, Visa) and the ISO7816
  smart card standards. One channel has extra control
  pins (smart card contact pad locations C4 and C8)
  to support existing memory cards. The entire chip is
  controlled by a microcontroller-friendly serial interface.
  Features
  The LTC1955 includes considerable security and functionality, yet remains easy to use. Two independent
  circuits detect the presence or absence of a smart …

Articles

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  Dual Smart Card Interface Simplifies Multicard Reader Designs &mdash LT Journal
  PDF, 355 Kb, File published: Mar 1, 2003
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  DESIGN FEATURES Dual Smart Card Interface Simplifies
  by Steven Martin
  Multicard Reader Designs
  Introduction
  The LTC1955 dual smart card interface provides a complete and compact
  solution for multicard applications.
  The LTC1955 and five small capacitors
  are all that are needed to interface two
  card sockets to a host microcontroller.
  Designed to comply with all smart card
  standards, the LTC1955 can be used
  for full sized card sockets, smaller
  vendor card (simlock) sockets, or any
  combination of smart card and vendor
  card sockets. Figure 1 shows the block diagram
  of the LTC1955, which operates from
  a battery or a regulated 3.3V supply.
  The internal charge pump delivers
  a boosted voltage to two on-chip
  low dropout regulators. The LDOs
  provide programmable 1.8V, 3V or
  5V regulated outputs to each of the
  smart card sockets. Two unidirectional channels and one bi-directional …

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Manufacturer's Classification

• Interface > SIM Interface

Other Names:

LTC1955EUHPBF, LTC1955EUH PBF