FXLP4555MPX Datasheet, PDF (3/13 Pages) Fairchild Semiconductor – 1.8V / 3.0V SIM Card Power Supply and Level Shifter

Pin Configuration
EN ¹
VSEL ²
VCCA ³
NC ⁴
16 15 14 13
FXLP4555
Exposed DAP
(GND)
56 78
12 _NC
11 _{CLK_C}
10 _GND
9 _{RST_C}
Figure 3. Pin Assignments (Top View)
Pin Definitions
Pin Name Type
Description
Power-Down Mode. EN=LOW → low-current Shutdown Mode activated. EN=HIGH →
1
EN
INPUT normal operation. A LOW level on this pin resets the SIM interface, switching off the
V_{CC_C}.
2
VSEL
INPUT
The signal present on this pin programs the SIM_V_CC value:
VSEL=LOW → SIM_V_CC=1.8V; VSEL=HIGH → SIM_V_CC=3V.
Connected to the baseband power supply; this pin configures the level shifter input
3
VCCA
POWER
stage to accept signals from the baseband. A 0.1µF capacitor is used to bypass the
power supply voltage. When V_CCA is below 1.1V (typical), the V_{CC_C} (SIM Card V_CC) is
disabled and FXLP4555 enters Shutdown Mode.
4
NC
No connect. It is recommended to solder to PCB GND.
5
VBAT
POWER
LDO converter supply input. The input voltage ranges from 2.7V to 5.5V. This pin
needs to be bypassed by a 0.1µF capacitor.
6
NC
No connect. It is recommended to solder to PCB GND.
Connected to the SIM card power supply pin. An internal LDO converter is
programmable by the external baseband to supply either 1.8V or 3.0V output voltage.
7 VCC_C POWER An external 1.0µF minimum ceramic capacitor must be connected across VCC_C and
GND. During a normal operation, the V_{CC_C} voltage can be set to 1.8V, followed by a
3.0V value, or can start directly at either of these values.
8
I/O_C
INPUT/
OUTPUT
Handles the connection to the serial I/O of the card connector. A bi-directional level
translator adapts the serial I/O signal between the card and the baseband. A 14kΩ
(typical) pull-up resistor provides a high-impedance state for the SIM card I/O link.
9
RST_C
OUTPUT
Connected to the RESET pin of the card connector. A level translator adapts the
external reset (RST) signal to the SIM card.
10
GND
GROUND
Ground reference for the integrated circuit and associated signals. Care must be
taken to avoid voltage spikes when the device operates in normal operation.
Connected to the CLOCK pin of the card connector. The CLOCK (CLK) signal comes
11 CLK_C OUTPUT from the external clock generator; the internal level shifter adapts the voltage defined
for the V_{CC_C}.
12
NC
No connect. It is recommended to solder to PCB GND.
13 CLK_H
INPUT
The clock signal, coming from the external controller, must have a duty cycle within
the range defined by the specification (typically 50%). The built-in level shifter
translates the input signal to the external SIM card CLK input.
© 2010 Fairchild Semiconductor Corporation
FXLP4555 • Rev. 1.0.0
3
www.fairchildsemi.com