LTC4555 - SIM Power Supply and Level Translator


  • SIM Power Supply: 1.8V/3V at 50mA
  • Input Voltage Range: 3V to 6V
  • Controller Voltage Range: 1.2V to 4.4V
  • 14kV ESD on all SIM Contact Pins
  • Meets all ETSI, IMT-2000 and ISO7816 SIM/Smart Card Interface Requirements
  • Level Translators to 1.8V or 3V
  • 20µA Operating Current
  • Logic Controlled Shutdown (ISD < 1µA)
  • Available in 0.75mm Profile, 3mm x 3mm QFN Package

Typical Application

LTC4555 Typical Application


The LTC4555 provides power conversion and signal level shifting needed for low voltage 2.5G and 3G cellular telephones to interface with 1.8V or 3V subscriber identity modules (SIMs). The part meets all type approval requirements for 1.8V and 3V SIMs and smart cards. The part contains an LDO linear regulator to supply SIM power at either 1.8V or 3V from a 3V to 6V input. The output voltage is selected with a single pin 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 20µA operating current and <1µA shutdown current. Board area is minimized by the 3mm x 3mm leadless 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
LTC4555EUD#PBF 3x3 QFN-16 UD E 05-08-1691 Yes
LTC4555EUD#TRPBF 3x3 QFN-16 UD E 05-08-1691 Yes

LTC4555 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
LTC4555EUD#PBF 3x3 QFN-16 E $1.71 $1.20 Yes
LTC4555EUD#TRPBF 3x3 QFN-16 E $1.26 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.

Click here to view our complete list of demo boards


  • SIM Interface in 3G Cellular Telephones
  • Smart Card Readers

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  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
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