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LTC4557

4557f

s

GSM and 3G Cellular Phones

s

Wireless P.O.S. Terminals

s

Multiple SAM Card Interface

s

Power Management and Signal Level Translators

for Two SIM Cards or Smart Cards

s

s

Automatic Level Translation

s

ISO7816, ETSI and EMV Compatible

s

Dynamic Pull-Ups Deliver Fast Signal Rise Times*

s

Built-In Fault Protection Circuitry

s

Automatic Activation/Deactivation Sequencing

Circuitry

s

Low Operating/Shutdown Current

s

>10kV ESD on SIM Card Pins

s

Compatible with EMV Fault Tolerance Requirements

s

Available in 16-Lead (3mm

× 3mm) QFN Package

Dual SIM/Smart Card

Power Supply and Interface

Deactivation Sequence

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

The LTC

translation needed for 2.5G and 3G cellular telephones to

interface with 1.8V or 3V subscriber identity modules

(SIMs). The part meets all requirements for 1.8V and 3V

SIMs. The part contains LDO regulators to power 1.8V or

3V SIM cards from a 2.7V to 5.5V input. The output

voltages can be set using the two voltage selection pins

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 a low operating current

of less than 100

µA and a shutdown current of less than

1

µA. Board area is minimized by the low profile 3mm ×

3mm

× 0.75mm leadless QFN package.

3V TO 6V

1.2V TO 4.4V

LTC4557

µCONTROLLER

I/OA

RSTA

CLKA

C1

C1

C5

C5

C3

C2

C7

C7

C2

C3

GND

CLKB

RSTB

I/OB

CLKIN

0.1

µF

1

µF

1

µF

RSTIN

DATA

ENABLE

M0

M1

0.1

µF

4557 TA01

1.8V/3V

SIM

CARD

1.8V/3V

SMART

CARD

I/O

RST

CLK

GND

GND

CLK

RST

I/O

*U.S. Patent No. 6,356,140

RSTX

5V/DIV

CLKX

5V/DIV

I/OX

5V/DIV

2V/DIV

10

µs/DIV

4557 G07

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO