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LTC1756

Smart Card Interface

February 2000

FEATURES

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Fully ISO 7816-3 and EMV Compliant

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Buck-Boost Charge Pump Generates 3V or 5V

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2.7V to 5.5V Input Voltage Range

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3V

↔ 5V Signal Level Translator

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> 10kV ESD on All Smart Card Pins

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Dynamic Pull-Ups Deliver Fast Signal Rise Times

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Soft Start Limits Inrush Current at Turn On

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Very Low Operating Current: 75

µA

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Shutdown Current: < 2.5

µA

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Short-Circuit and Overtemperature Protected

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Available in 16-Pin SSOP Package

The LTC

compliant with ISO 7816-3 and EMV specifications. It

provides the smallest and simplest interface circuit be-

tween a host microcontroller and general purpose Smart

Cards.

An internal charge pump DC/DC converter delivers regu-

lated 3V or 5V to the Smart Card, while an on-chip level

shifter allows a connection to a low voltage controller. All

Smart Card contacts are rated for 10kV ESD, eliminating

the need for external ESD protection devices.

Input voltage may range from 2.7V to 5.5V, allowing direct

connection to a battery. Automatic DC/DC converter soft

start mitigates start-up problems that may result when the

input power is provided by another regulator.

Battery life is maximized by 75

µA operating current and

2

µA shutdown current. The 16-pin SSOP package mini-

mizes PCB area for compact portable systems.

, LTC and LT are registered trademarks of Linear Technology Corporation.

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Handheld Payment Terminals

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Pay Telephones

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ATMs

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Key Chain Readers

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Smart Card Readers

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

Final Electrical Specifications

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2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

LTC1756

PRES

PWR

GND

I/O

RST

CLK

C2

10

µF

N.O.

C3

10

µF

I/O

RST

CLK

C1

0.68

µF

GND

SMART CARD

1756 TA01

SMART CARD

PRESENT SWITCH

µCONTROLLER

3.3V

5V/3V

CARD

READY

DATA

RIN

CIN