LTC4555
SIM Power Supply
and Level Translator
FEATURES
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DESCRIPTION
The LTC
®
4555 provides power conversion and signal
level shifting needed for low voltage 2.5G and 3G cellular
telephones to interface with 1.8V or 3V subscriber identity
modules (SIMs). The part meets all type approval require-
ments for 1.8V and 3V SIMs and smart cards. The part
contains an LDO linear regulator to supply SIM power at
either 1.8V or 3V from a 3V to 6V input. The output volt-
age is selected with a single pin 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 20μA operating current
and <1μA shutdown current. Board area is minimized by
the 3mm
×
3mm leadless QFN package.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
SIM Power Supply: 1.8V/3V at 50mA
Input Voltage Range: 3V to 6V
Controller Voltage Range: 1.2V to 4.4V
14kV ESD On All SIM Contact Pins
Meets All ETSI, IMT-2000 and ISO7816 SIM/Smart
Card Interface Requirements
Level Translators to 1.8V or 3V
20μA Operating Current
Logic-Controlled Shutdown (I
SD
< 1μA)
Available in a Low Profile, 16-Pin (3mm
×
3mm)
QFN Package
APPLICATIONS
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SIM Interface in 3G Cellular Telephones
Smart Card Readers
TYPICAL APPLICATION
Typical SIM Interface
(1.2V TO 4.4V)
V
CC
0.1μF
DV
CC
SHDN
CONTROLLER
V
SEL
LTC4555
R
IN
C
IN
DATA
GND
GND
4555 TA01
V
BAT
(3V TO 6V)
0.1μF
V
BAT
V
CC
1μF
RST
CLK
I/0
RST
CLK
I/0
V
CC
SIM/
SMART CARD
INTERFACE
4555fb
1
LTC4555
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
DATA
R
IN
C
IN
12 NC
17
11 CLK
10 GND
9
5
V
BAT
6
NC
7
V
CC
8
I/O
RST
NC
SHDN
1
V
SEL
2
DV
CC
3
NC 4
V
BAT
, DV
CC
, V
CC
to GND ............................ –0.3V to 6.5V
Digital Inputs to GND ................................ –0.3V to 6.5V
CLK, RST, I/O to GND .......................–0.3V to V
CC
+ 0.3V
V
CC
Short-Circuit Duration ................................... Infinite
Operating Temperature Range (Note 2).... –40°C to 85°C
Junction Temperature ........................................... 125°C
Storage Temperature Range................... –65°C to 125°C
16 15 14 13
UD PACKAGE
16-LEAD (3mm 3mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 68°C/W,
θ
JC
= 4.2°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC4555EUD#PBF
TAPE AND REEL
LTC4555EUD#TRPBF
PART MARKING
LAAA
PACKAGE DESCRIPTION
16-Lead (3mm
×
3mm) Plastic QFN
TEMPERATURE RANGE
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
ELECTRICAL CHARACTERISTICS
PARAMETER
V
BAT
Operating Voltage
V
BAT
Operating Current
V
BAT
Shutdown Current
DV
CC
Operating Voltage
DV
CC
Operating Current
DV
CC
Shutdown Current
DV
CC
Undervoltage Lockout
V
CC
Output Voltage
f
CLK
= 1MHz
SHDN
= 0V
I
CC
= 0mA
CONDITIONS
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C.
MIN
l
l
l
l
l
l
l
TYP
20
MAX
6
30
1
4.4
UNITS
V
μA
μA
V
μA
μA
V
V
V
V
mA
V
nA
V
V
V
V
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3
SHDN
= 0V, V
BAT
= 4.5V
1.2
5
0.5
2.8
1.7
60
0
2.8
3.0
1.8
110
10
1
1.1
3.2
1.9
175
DV
CC
100
0.7
×
DV
CC
V
SEL
= DV
CC
, V
BAT
= 3V, I
VCC
= 50mA
V
SEL
= DV
CC
, V
BAT
= 3.3V to 6V, I
VCC
= 0mA to 50mA
V
SEL
= 0, V
BAT
= 2.6V to 6V, I
VCC
= 0mA to 50mA
V
CC
Shorted to GND
SHDN,
V
SEL
, R
IN
, C
IN
, DATA
SHDN,
V
SEL
, R
IN
, C
IN
R
IN
, C
IN
R
IN
, C
IN
SHDN,
V
SEL
SHDN,
V
SEL
l
l
V
CC
Short-Circuit Current
Controller Inputs/Outputs
Input Voltage Range
Input Current (I
IH
/I
IL
)
High Input Threshold Voltage (V
IH
)
Low Input Threshold Voltage (V
IL
)
High Input Threshold Voltage (V
IH
)
Low Input Threshold Voltage (V
IL
)
l
l
l
l
l
–100
0.2
×
DV
CC
1
0.4
2
LTC4555
ELECTRICAL CHARACTERISTICS
PARAMETER
High Level Input Current (I
IH
)
Low Level Input Current (I
IL
)
High Level Output Voltage (V
OH
)
Low Level Output Voltage (V
OL
)
DATA Pull-Up Resistance
SIM Inputs/Outputs (V
CC
= 3V)
High Level Output Voltage (V
OH
)
Low Level Output Voltage (V
OL
)
High Level Output Voltage (V
OH
)
Low Level Output Voltage (V
OL
)
I/O Pull-Up Resistance
SIM Inputs/Outputs (V
CC
= 1.8V)
High Level Output Voltage (V
OH
)
Low Level Output Voltage (V
OL
)
High Level Output Voltage (V
OH
)
Low Level Output Voltage (V
OL
)
I/O Pull-Up Resistance
SIM Timing Parameters
CLK Rise/Fall Time
RST, I/O Rise/Fall Time
Max CLK Frequency
V
CC
Turn-On Time
V
CC
Discharge Time to 1V
SHDN
= 1, (Note 3)
SHDN
= 0, (Note 3)
,
C
CLK
= 30pF V
CC
= 1.8V/3V
RST, I/O Loaded with 30pF V
CC
= 1.8V/3V
,
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C.
CONDITIONS
DATA
DATA
DATA I
OH
= 20μA, I/O = V
CC
DATA I
OL
= –200μA, I/O = 0V
Between DATA and DV
CC
I/O, I
OH
= 20μA, DATA = DV
CC
I/O, I
OL
= –1mA, DATA = 0V
RST, CLK, I
OH
= 20μA
RST, CLK, I
OL
= –200μA
Between I/O and V
CC
I/O, I
OH
= 20μA, DATA = DV
CC
I/O, I
OL
= –1mA, DATA = 0V
RST, CLK, I
OH
= 20μA
RST, CLK, I
OL
= –200μA
Between I/O and V
CC
l
l
l
l
l
l
l
l
l
l
l
l
MIN
–20
0.7
×
DV
CC
TYP
MAX
20
1
0.4
UNITS
μA
mA
V
V
kΩ
V
13
0.8
×
V
CC
20
30
0.4
0.9
×
V
CC
0.4
6.5
0.8
×
V
CC
0.3
0.9
×
V
CC
0.2
×
V
CC
6.5
10
14
18
1
5
0.5
0.5
10
14
V
V
V
kΩ
V
V
V
V
kΩ
ns
μs
MHz
ms
ms
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
The LTC4555E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3:
Specification is guaranteed by design and not 100% tested in
production.
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LTC4555
TYPICAL PERFORMANCE CHARACTERISTICS
V
CC
Short-Circuit Current
170
SHORT-CIRCUIT CURRENT (mA)
150
130
I
BAT
(μA)
110
90
70
50
–40 –20
22
V
CC
= 3V
20
T
A
= 25°C
18
16
14
12
10
2.5
T
A
= 85°C
T
A
= –40°C
T
A
= 25°C
T
A
= 85°C
V
CC
= 1.8V
T
A
= –40°C
I
BAT
vs V
BAT
40
20
60
0
TEMPERATURE (°C)
80
100
4555 G01
3.0
3.5
4.0 4.5
V
BAT
(V)
5.0
5.5
6.0
4555 G02
PIN FUNCTIONS
SHDN
(Pin 1):
Controller Driven Shutdown Pin. This pin
should be high (DV
CC
) for normal operation and low to
activate a low current shutdown mode.
V
SEL
(Pin 2):
V
CC
Voltage Select Pin. A low level selects V
CC
= 1.8V while driving this pin to DV
CC
selects V
CC
= 3V.
DV
CC
(Pin 3):
Supply Voltage for the Controller Side I/O
Pins (C
IN
, R
IN
, DATA). When below 1.1V, the V
CC
supply
is disabled. This pin should be bypassed with a 0.1μF
ceramic capacitor close to the pin.
NC (Pins 4, 6, 12, 16):
No Connect.
V
BAT
(Pin 5):
V
CC
Supply Input. This pin can be between
3V and 6V for normal operation. V
BAT
quiescent current
reduces to <1μA in shutdown. This pin should be bypassed
with a 0.1μF ceramic capacitor close to the pin.
V
CC
(Pin 7):
SIM Card V
CC
Supply. A 1μF low ESR capacitor
needs to be connected close to the V
CC
pin for stable opera-
tion. This pin is discharged to GND during shutdown.
I/O (Pin 8):
SIM-Side Data I/O. The SIM card output must
be on an open-drain driver capable of sourcing >1mA.
RST (Pin 9):
Reset Output Pin for the SIM Card.
GND (Pin 10):
Ground for the SIM and Controller. Proper
grounding and bypassing is required to meet 14kV ESD
specifications.
CLK (Pin 11):
Clock Output Pin for the SIM Card. This
pin is pulled to ground during shutdown. Fast rising and
falling edges necessitate careful board layout for the CLK
node.
C
IN
(Pin 13):
Clock Input from the Controller.
R
IN
(Pin 14):
Reset Input from the Controller.
DATA (Pin 15):
Controller Side Data I/O. This pin is used
for bidirectional data transfer. The controller output must
be an open-drain configuration. The open-drain output
must be capable of sinking greater than 1mA.
Exposed Pad (Pin 17):
GND. Must be soldered to PCB.
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LTC4555
BLOCK DIAGRAM
V
BAT
(3V TO 6V)
PROCESSOR
V
CC
C3
0.1μF
SHUTDOWN
PIN
V
SIM
VOLTAGE
SELECT
RESET
FROM
PROCESSOR
CLOCK
FROM
PROCESSOR
1
SHDN
3
5
C2
0.1μF
V
CC
50mA LDO
7
1.8V/3V
AT 50mA
DV
CC
V
BAT
2
V
SEL
C1
1μF
14
R
IN
RST
9
RESET
13
C
IN
20k
10k
CLK
11
CLOCK
DATA TO/
FROM SIM
15
DATA
I/0
8
BIDIRECTIONAL
I/O
CELL PHONE
PROCESSOR
INTERFACE
LTC4555
10
GND
SIM/
SMART CARD
INTERFACE
4555 BD
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