LTC1555 - SIM Power Supplyand Level Translator

Features

  • Step-Up/Step-Down Charge Pump Generates 5V
  • Input Voltage Range: 2.7V to 10V
  • Output Current: 10mA (VIN >/= 2.7V) 20mA (VIN >/=3V)
  • 3V to 5V Signal Level Translators
  • >10kV ESD on All SIM Contact Pins
  • Short-Circuit and Overtemperature Protected
  • Very Low Operating Current: 60µA
  • Very Low Shutdown Current: <1µA
  • Soft Start Limits Inrush Current at Turn-On
  • Programmable 3V or 5V Output Voltage
  • 650kHz Switching Frequency
  • Auxiliary 4.3V LDO/Power Switch (LTC1556 Only)
  • Available in a 16- and 20-Pin Narrow SSOP

Typical Application

LTC1555 Typical Application

Description

The LTC1555/LTC1556 provide power conversion and level shifting needed for 3V GSM cellular telephones to interface with either 3V or 5V Subscriber Identity Modules (SIMs). These parts contain a charge pump DC/DC converter that delivers a regulated 5V to the SIM card. Input voltage may range from 2.7V to 10V, allowing direct connection to the battery. Output voltage may be programmed to 3V, 5V or direct connection to the VIN pin.

A soft start feature limits inrush current at turn-on, mitigating start-up problems that may result when the input is supplied by another low power DC/DC converter. The LTC1556 also includes an auxiliary LDO regulator/power switch that may be used to power the frequency synthesizer or other low power circuitry.

Battery life is maximized by 60µA operating current and 1µA shutdown current. Board area is minimized by miniature 16- and 20-pin narrow SSOP packages and the need for only three small external capacitors.

Packaging

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
Drawing
RoHS
LTC1555CGN#PBF SSOP-16 GN C 05-08-1641 (GN16) Yes
LTC1555CGN#TRPBF SSOP-16 GN C 05-08-1641 (GN16) Yes
LTC1555IGN#PBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LTC1555IGN#TRPBF SSOP-16 GN I 05-08-1641 (GN16) Yes


LTC1555 Package Drawing
LTC1555 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
(1-99)
Price
(1k)*
RoHS
LTC1555CGN#PBF SSOP-16 C $3.60 $2.85 Yes
LTC1555CGN#TRPBF SSOP-16 C $2.91 Yes
LTC1555IGN#PBF SSOP-16 I $4.30 $3.45 Yes
LTC1555IGN#TRPBF SSOP-16 I $3.51 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

Applications

  • SIM Interface in GSM Cellular Telephones
  • Smart Card Readers

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Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
  • LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
  • And More!

Technical Support