LTC4557EUD Linear Technology, LTC4557EUD Datasheet - Page 9

• Manufacturer Part Number: LTC4557EUD
• Description: IC DUAL SIM/SMART CARD PS 16QFN
• Manufacturer: Linear Technology

Specifications of LTC4557EUD

• Function: Power Management, Signal Level Translation
• Rf Type: Cellular, 3G, GSM
• Secondary Attributes: SIM & Smart Card Interface
• Package / Case: 16-WFQFN Exposed Pad
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
10kV ESD Protection
All smart card pins (CLKA,B, RSTA,B, I/OA,B, V
GND) can withstand over 10kV of human body model ESD
in-situ. In order to ensure proper ESD protection, careful
board layout is required. The GND pad should be tied
directly to a ground plane. The V
located very close to the V
to the ground plane.
Capacitor Selection
A total of four capacitors are required for proper bypassing
of the LTC4557. An input bypass capacitor is required at
V
each of the smart card V
low equivalent series resistance (ESR), only multilayer
ceramic chip capacitors should be used to ensure proper
stability and ESD protection.
There are several types of ceramic capacitors available
each having considerably different characteristics. For
example, X7R/X5R ceramic capacitors have excellent volt-
age and temperature stability but relatively low packing
density. Y5V ceramic capacitors have apparently higher
packing density but poor performance over their rated
voltage or temperature ranges. Under certain voltage and
temperature conditions Y5V and X7R/X5R ceramic
BATT
and DV
CC
. Output bypass capacitors are required on
U
CCA,B
U
CCA,B
pins. Due to their extremely
Figure 2. Additional Components for Improved Compliance Testing
CCA,B
pins and tied immediately
W
capacitors should be
LTC4557
RSTX
CLKX
V
I/OX
CCX
U
CCA,B
100
100
100
20pF
and
20pF
1 F
20pF
capacitors can be compared directly by case size rather
than specified value for a desired minimum capacitance.
The V
capacitor. V
capacitor. Capacitors should be placed as close to the
LTC4557 as possible for improved ESD tolerance.
The following capacitors are recommended for use with
the LTC4557:
C
V
C
DV
Compliance Testing
Inductance due to long leads on type approval equipment
can cause ringing and overshoot that leads to testing
problems. Small amounts of capacitance and damping
resistors can be included in the application without com-
promising the normal electrical performance of the
LTC4557 or smart card system. Generally a 100 resistor
and a 20pF capacitor will accomplish this as shown in
Figure 2.
VCC
CCA/B
DVCC
0.1 F
CC
,
,
CCA,B
TYPE
C1
C3
C2
C7 C5
outputs should be bypassed to GND with a 1 F
X5R
X5R
BATT
SOCKET
SMART
CARD
4557 F02
should be bypassed with a 0.1 F ceramic
VALUE
0.1 F
1 F
CASE SIZE MURATA PART NUMBER
0603
0402
GRM188R60J105KA01
GRM155R61A104KA01
LTC4557
9
4557f