LTC4558
Dual SIM/Smart Card
Power Supply and Interface
FEATURES
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
pindetermineswhichchannelisopenforcommunication.
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.
■
Power Management and Control for Two SIM Cards
or Smart Cards
■
Independent 1.8V/3V V Control for Both Cards
CC
■
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
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.
■
Low Profile 20-Lead (3mm × 3mm) QFN Package
APPLICATIONS
+
■
GSM, TD-SCDMA and other 3G Cellular Phones
■
Wireless Point-of-Sale Terminals
, 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.
■
Multiple SIM Card Interfaces
TYPICAL APPLICATION
DV
CC
V
BATT
1.4V TO 4.4V 3V TO 6V
DV
CC
Deactivation Sequence
0.1µF
0.1µF
DV
CC
V
BATT
C7
C2
C3
C1
CLKIN
I/OA
I/O
RSTX
RSTIN
RSTA
CLKA
RST
CLK
1.8V/3V
5V/DIV
SIM
DATA
CARD A
CLKX
5V/DIV
V
CCA
V
CC
CLKRUNA
CLKRUNB
GND
µCONTROLLER
1µF
1µF
C5
GND
I/OX
5V/DIV
ENABLEA
ENABLEB
CSEL
C1
C3
C2
C7
V
V
CCB
V
CC
CCX
2V/DIV
CLKB
RSTB
I/OB
CLK
RST
I/O
1.8V/3V
SIM
CARD B
4558 TA02
C
= 1µF
10µs/DIV
VCCX
VSELA
VSELB
GND
C5
LTC4558
4558 TA01
4558f
1