LTC4556 - Smart Card Interface with Serial Control


  • Electrical Specifications Are ISO7816-3 and EMV Compatible
  • Control/Status Serial Port May be Daisy-Chained for Multicard Applications
  • Automatic Shutdown on Electrical Faults
  • Buck Boost Charge Pump Generates 5V, 3V or 1.8V Outputs (Smart Card Classes A, B and C)
  • Automatic Level Translation
  • Dynamic Pull-Ups Deliver Fast Signal Rise Times
  • Supervisory Functions Prevent Smart Card Faults
  • Low Operating Current: 250μA Typical
  • VIN: 2.7V to 5.5V
  • Ultralow Shutdown Current
  • >10kV ESD on Smart Card Pins
  • Small 24-Lead 4mm × 4mm QFN Package

Typical Application

LTC4556 Typical Application
LTC4556 Typical Application


The LTC®4556 provides all necessary power control, level translation and supervisory functions for a smart card or S.A.M. card interface. The part contains a low noise charge pump plus LDO for generating VCC power, as well as all necessary level shifting circuitry.

The card voltage can be set to either 1.8V, 3V or 5V. The LTC4556 includes a card detection channel with automatic debounce circuitry. To reduce wiring costs, the LTC4556 interfaces to a microcontroller via a simple 4‑wire serial interface. Multiple devices may be connected in daisy-chain fashion so that the number of wires to the card socket board is independent of the number of sockets. Status data is returned over the same interface.

Extensive security features ensure proper deactivation sequencing in the event of a supply fault or a smart card electrical fault. The smart card pins can withstand greater than 10kV ESD in-situ with no additional components. The LTC4556 is available in a small, low profile (0.75mm), 4mm × 4mm QFN package.


CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
LTC4556EUF#PBF 4x4 QFN-24 UF E 05-08-1697 Yes
LTC4556EUF#TRPBF 4x4 QFN-24 UF E 05-08-1697 Yes

LTC4556 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
LTC4556EUF#PBF 4x4 QFN-24 E $2.68 $1.85 Yes
LTC4556EUF#TRPBF 4x4 QFN-24 E $1.95 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC564A LTC4556EUF | Single Smart Card Interface, VBATT=2.7V-5.5V, DVCC=3V-5.5V $100.00
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Click here to view our complete list of demo boards


  • Handheld Payment Terminals
  • Pay Telephones
  • ATM Machines
  • POS Terminals
  • Computer Keyboards
  • Multiple S.A.M. Sockets

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