LTC4558_15 Datasheet, PDF (1/12 Pages) Linear Technology – Dual SIM/Smart Card Power Supply and Interface

LTC4558
Dual SIM/Smart Card
Power Supply and Interface
FEATURES
■ _{Power Management and Control for Two SIM Cards}
or Smart Cards
■ _{Independent 1.8V/3V VCC Control for Both Cards}
■ _{Supports Simultaneous Powering of Both Cards}
■ _{Fast Channel Switching}
■ _{Automatic Level Translation}
■ _{Dynamic Pull-Ups Deliver Fast Signal Rise Times*}
■ _{Built-In Fault Protection Circuitry}
■ _{Automatic Activation/Deactivation Sequencing}
Circuitry
■ _{Low Operating/Shutdown Current}
■ _{> 10kV ESD on SIM Card Pins}
■ _{Meets EMV Fault Tolerance Requirements}
■ _{Low Profile 20-Lead (3mm × 3mm) QFN Package}
APPLICATIONS
■ _{GSM, TD-SCDMA and other 3G}⁺ _{Cellular Phones}
■ _{Wireless Point-of-Sale Terminals}
■ _{Multiple SIM Card Interfaces}
DESCRIPTION
The LTC^®4558 provides the power conversion and signal
level translation needed for advanced cellular telephones
to interface with 1.8V or 3V subscriber identity modules
(SIMs). The device meets all requirements for 1.8V and
3V SIMs and 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. A channel select
pin determines which channel is open for communication.
Separate enable pins for each channel allow both cards to
be powered at once and allow for faster transition from
one channel to the other.
Internal level translators allow controllers operating with
supplies as low as 1.4V to interface with 1.8V or 3V Smart
Cards. Battery life is maximized by a low operating cur-
rent of 65μA and a shutdown current of less than 1μA.
Board area is minimized by the low profile 3mm × 3mm
× 0.75mm leadless QFN package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Protected by U.S. Patents, including 6356140.
TYPICAL APPLICATION
DV_CC
μCONTROLLER
DV_CC
V_BATT
1.4V TO 4.4V 3V TO 6V
0.1μF
DV_CC
CLKIN
V_BATT
I/OA
RSTIN RSTA
DATA
CLKA
CLKRUNA ^VCCA
CLKRUNB
GND
ENABLEA
ENABLEB V_CCB
CSEL
CLKB
VSELA RSTB
VSELB
I/OB
LTC4558
0.1μF
1μF
1μF
C7
I/O
C2
RST
C3
CLK
C1
1.8V/3V
SIM
CARD A
V_CC
GND
C5
C1
V_CC
C3
CLK
1.8V/3V
C2
RST
C7
I/O
SIM
CARD B
GND
C5
4558 TA01
Deactivation Sequence
RSTX
5V/DIV
CLKX
5V/DIV
I/OX
5V/DIV
V_CCX
2V/DIV
C_VCCX = 1μF
10μs/DIV
4558 TA02
4558fa
1