LTC4555EUD Linear Technology, LTC4555EUD Datasheet - Page 6

• Manufacturer Part Number: LTC4555EUD
• Description: IC SIM PWR SUP/LVL TRNSLTR 16QFN
• Manufacturer: Linear Technology

Specifications of LTC4555EUD

• Function: Power Management, Signal Level Translation
• Rf Type: Cellular
• Secondary Attributes: SIM & Smart Card Interface
• Package / Case: 16-WFQFN Exposed Pad
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

LTC4555
APPLICATIONS INFORMATION
The LTC4555 provides both regulated power and internal
level translators to allow low voltage controllers to interface
with 1.8V or 3V SIMs or smart cards. The part meets all
ETSI, IMT-2000 and ISO7816 requirements for SIM and
smart card interfaces.
V
The V
regulator with a digitally selected 1.8V or 3V output.
The output voltage is selected via the V
is internally current limited and is capable of surviving an
indefi nite short to GND.
The V
The LTC4555 can use either a low ESR ceramic capacitor
or a tantalum electrolytic capacitor on the V
no special ESR requirements.
V
Level Translators
All SIMs and smart cards contain a clock input, a reset
input and a bidirectional data input/output. The LTC4555
6
CC
BAT
Voltage Regulator
should be bypassed with a 0.1μF ceramic capacitor.
CC
CC
output should be bypassed with a 1μF capacitor.
voltage regulator is a 50mA low dropout (LDO)
SEL
pin. The output
CC
pin, with
provides level translators to allow controllers to com-
municate with the SIM. The CLK and RST lines to the
SIM are level shifted from the controller supply (GND to
DV
the SIM requires an open-drain output on the controller.
On-chip pull-up resistors are provided for both the DATA
and I/O lines.
Shutdown Modes
The LTC4555 enters a low current shutdown mode by
pulling the SHDN pin low. The SHDN pin is an active low
input that the controller can use to directly shut down
the part.
ESD Protection
All pins that connect to the SIM/smart card will withstand
14kV of human body model ESD. In order to ensure
proper ESD protection, careful board layout is required.
The GND pin should be tied directly to a GND plane. The
V
and tied directly to the GND plane.
CC
CC
capacitor should be located very close to the V
) to the SIM supply (GND to V
CC
). The data input to
CC
4555fb
pin