LTC4557 Datasheet, PDF (1/12 Pages) Linear Technology – Dual SIM/Smart Card Power Supply and Interface

LTC4557
Dual SIM/Smart Card
Power Supply and Interface
FEATURES
s _{Power Management and Signal Level Translators}
for Two SIM Cards or Smart Cards
s _{Independent 1.8V/3V VCC Control for Both Cards}
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}
U
APPLICATIO S
s _{GSM and 3G Cellular Phones}
s _{Wireless P.O.S. Terminals}
s _{Multiple SAM Card Interface}
DESCRIPTIO
The LTC^®4557 provides power conversion and signal level
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 100µA and a shutdown current of less than
1µA. Board area is minimized by the low profile 3mm ×
3mm × 0.75mm leadless QFN package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
*U.S. Patent No. 6,356,140
TYPICAL APPLICATIO
DV_CC
µCONTROLLER
DV_CC
V_BATT
1.2V TO 4.4V 3V TO 6V
0.1µF
DV_CC
CLKIN
V_BATT
I/OA
RSTIN RSTA
DATA
CLKA
V_CCA
LTC4557
GND
ENABLE
M0
M1
V_CCB
CLKB
RSTB
I/OB
0.1µF
1µF
1µF
C7
I/O
C2
RST _1.8V/3V
C3
C1
CLK
SIM
CARD
V_CC
GND
C5
C1
V_CC
C3
CLK _1.8V/3V
C2
C7
RST
SMART
CARD
I/O
GND
C5
4557 TA01
Deactivation Sequence
RSTX
5V/DIV
CLKX
5V/DIV
I/OX
5V/DIV
V_CCX
2V/DIV
C_VCCX = 1µF
10µs/DIV
4557 G07
4557f
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