SEMTECH STF701

STF701
T-Filter with TVS Diode Array
For EMI Filtering and ESD Protection
PROTECTION PRODUCTS
Description
Features
u Bidirectional EMI/RFI filtering with integrated ESD
The STF701 is a low pass T-filter with integrated TVS
diodes. It is designed to provide bi-directional unwanted EMI/RFI signals filtering and electrostatic
discharge (ESD) protection in portable electronic
equipment. Each device will provide filtering and
protection for two I/O lines.
The STF701 is constructed using thin-film-on-silicon
technology. The device has very low insertion loss in
the pass band (to approximately 10MHz) and good
attenuation at high frequencies (approximately
100MHz to 1GHz). Each line features two stages of
TVS diode protection. The TVS diodes provide effective suppression of ESD voltages in excess of 15kV (air
discharge) and 8kV (contact discharge) per IEC 610004-2, level 4.
The clamping characteristics of the device are optimized by the use of two TVS diodes. The TVS diodes
serve a dual purpose of protecting the internal capacitor and the sensitive IC connected to the line. The
voltage divider action of the circuit means the voltage
across the protected IC will be very close to the breakdown voltage (VBR) of the second TVS.
The small size and integrated feature of the STF701
minimizes required board space and increases system
reliability. The STF701 is suitable for use in portable
communications devices such as cellular handsets and
accessory kits.
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protection
ESD protection to IEC 61000-4-2 Level 4
Filtering and ESD protection for two data lines
Low insertion loss to 10MHz
Good attenuation of high frequency signals
Low TVS operating voltage (5V)
Low clamping voltage
Low leakage current
Thin-film-on-silicon technology
Mechanical Characteristics
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EIAJ SC70-5L package
Molding compound flammability rating: UL 94V-0
Marking : 701
Packaging : Tape and Reel per EIA 481
Applications
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Circuit Diagram
Cell phone handsets
Cell phone accessories
RF Communications equipment
Laptop Computers
Two-way pagers
GPS Devices
Schematic & PIN Configuration
SC70-5L (Top View)
Revision 9/2000
1
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STF701
PROTECTION PRODUCTS
Absolute Maximum Rating
R ating
Symbo l
Value
Units
Steady-State Pow er
Pp k
100
mW
ESD Air Discharge p er IEC 61000-4-2
V PP
15
kV
ESD Contact Discharge p er IEC 61000-4-2
V PP
8
kV
Lead Soldering Temp erature
TL
260 (10 sec.)
°C
Op erating Temp erature
TJ
-20 to +125
°C
TSTG
-55 to +150
°C
Storage Temp erature
Electrical Characteristics
STF701
Par ame te r
Symbo l
Co nd itio ns
Minimum
Typ ical
Maximum
Units
5
V
T VS Reverse Stand-Off Voltage
V RWM
T VS Reverse Breakdow n Voltage
V BR
It = 1mA
T VS Reverse Leakage Current
IR
VRWM = 5V, T=25°C
5
µA
T VS Reverse Leakage Current
IR
VRWM = 3.3V, T=25°C
1
µA
T VS Junction Cap acitance
Cj
Betw een I/O p ins and
Gnd, each device
V R = 0V, f = 1MHz
Total Series Resistance
R
Each Line
Cap acitor
C
Each Line
100
pF
CTOT
Betw een Inp ut and
Outp ut, each Line
V R = 0V, f = 1MHz
230
pF
Total Cap acitance
ã 2000 Semtech Corp.
2
6
V
65
45
50
V
55
W
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STF701
PROTECTION PRODUCTS
Typical Characteristics
Normalized Resistance vs. Temperature
1.1
1.1
1.05
1.05
|R|
|VBR|
Normalized Breakdown Voltage vs. Temperature
1
0.95
1
0.95
0.9
0.9
-40
10
60
110
-40
Temperature (OC)
Atte nuatio n
100MHz
-10.75dB
1GHz
-14.71dB
60
110
Temperature (OC)
ESD Clamping
(8kV Contact per IEC 61000-4-2)
Typical Insertion Loss
Fr e que ncy
10
Measurement taken with Hewlett Packard Model
8753E Network Analyzer
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STF701
PROTECTION PRODUCTS
Applications Information
Device Connection for Protection of Two Data Lines
Figure 1 - STF701 Circuit Diagram
The STF701 is designed to provide EMI filtering and
ESD protection for two I/O lines. The equivalent circuit
diagram is shown in Figure 1. The device is connected
as follows:
1. Line 1 is connected at pins 1 & 5 and line 2 is
connected at pins 3 & 4 (Figure 2). The device is
symmetrical so input & output connections can be
made on either side of the device. Pin 2 is connected to ground. The ground connection should
be made directly to the ground plane for best
results. The path length is kept as short as possible to reduce the effects of parasitic inductance
in the board traces.
Figure 2 - STF701 Connection Diagram
Voltage Clamping Characteristics.
The clamping characteristics of the STF701 are optimized by the use of two TVS diodes in the protection
circuit (Figure 3). An ESD strike on the protected line
will be initially suppressed by the first TVS diode. The
voltage across the TVS will be the clamping voltage of
the device (VC1) given by:
VC1 = Vbr + RD * IPP
where
Vbr = Breakdown voltage of the TVS
RD = Dynamic resistance of the TVS
IPP = Peak pulse (ESD) current
Figure 3 - STF701 Clamping Characteristics
The dynamic resistance of the TVS is very small,
typically < 0.5W.
The second TVS will be subjected to VC1 through the
voltage divider formed by the series resistor (R) and
the dynamic resistance of the TVS. Since R >> RD
then by the voltage divider theorem, the voltage seen
by the protected IC will be a few millivolts above the
breakdown voltage (Vbr) of the second TVS.
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STF701
PROTECTION PRODUCTS
Outline Drawing - SC70-5L
Land Pattern - SC70-5L
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STF701
PROTECTION PRODUCTS
Marking Codes
Par t Numbe r
Mar king
Co d e
STF701
F1
Ordering Information
Par t Numbe r
Wo r king
Vo ltage
Qty p e r R e e l
R e e l Size
STF701.TC
5V
3,000
7 Inch
STF701.TG
5V
10,000
13 Inch
Contact Information
Semtech Corporation
Protection Products Division
652 Mitchell Rd., Newbury Park, CA 91320
Phone: (805)498-2111 FAX (805)498-3804
ã 2000 Semtech Corp.
6
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