MIC4555_11 Datasheet, PDF (12/16 Pages) Micrel Semiconductor – SIM Card Level Shifter with 50mA LDO

Micrel Inc.
Functional Description
EN
The EN pin is the enable input from the controller. A
logic high signal enables the level shifters and the V_CC
output. A logic low signal disables the level shifters and
the LDO and a low current shutdown mode is activated.
V_SEL
V_SEL selects the level shifted voltage for the SIM Card. A
high logic voltage on V_SEL selects the level shifter to 3V.
A low logic voltage on V_SEL selects the level shifter to
1.8V. Do not leave floating.
DV_CC
The DV_CC is the supply voltage for the controller side
input and output pins (CIN, RIN, DATA). The operating
range is from 1.6V to V_BAT. A minimum 1µF input
capacitor with a minimum voltage rating of 6.3V placed
close to DV_CC and ground (GND) is required. Refer to the
Layout Recommendations for details.
V_BAT
The V_BAT is the input power supply to the LDO. The
operating range is from 2.7V to 5.5V. A minimum 1µF
input capacitor with a minimum voltage rating of 6.3V to
ground (GND) is required. Refer to the Layout
Recommendations for details.
V_CC
The V_CC is the output of the LDO and provides power to
the SIM card. A minimum 1µF input capacitor with a
minimum voltage rating of 6.3V to ground (GND) is
required. Refer to the Layout Recommendations for
details.
GND
The ground pin (GND) is the ground path for the biasing,
the control circuitry and the power ground. The current
loop for the ground should be kept as short as possible.
Refer to the Layout Recommendations for more details.
MIC4555
RIN, RST
RIN is the digital reset input for the SIM Card and
translates to RST through the digital level shifter. It is
one directional. If V_SEL is low, then the input at RIN will
be level shifted to 1.8V at the RST output. If V_SEL is high,
then the input at RST will be level shifted to 3V at the
RST output.
CIN, CLK
CIN is the digital input clock for SIM card. The CIN
translates to CLK and is one directional. If V_SEL is low,
then the input at CLKIN will be level shifted to 1.8V at
the CLK output. If V_SEL is high, then the input at CIN will
be level shifted to 3V at the CLK output.
DATA, I/O
DATA is the digital data for the SIM card. The DATA
translate to I/O through the digital level shifter and is
bidirectional using internal pull ups. If V_SEL is low, then
the level shifted output is 1.8V at the I/O output. If V_SEL is
high, then the level shifted output is 3V at the I/O output.
Since DATA and I/O are bidirectional, the input at I/O is
level shifted to equal the DV_CC voltage at the DATA
output.
September 2011
12
M9999-092311-B