PROTECTION PRODUCTS
PROTECTION PRODUCTS
STF701
T-Filter with TVS Diode Array
For EMI Filtering and ESD Protection
Description
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 (V
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.
) of the second TVS.
BR
Features
u Bidirectional EMI/RFI filtering with integrated ESD
protection
u ESD protection to IEC 61000-4-2 Level 4
u Filtering and ESD protection for two data lines
u Low insertion loss to 10MHz
u Good attenuation of high frequency signals
u Low TVS operating voltage (5V)
u Low clamping voltage
u Low leakage current
u Thin-film-on-silicon technology
Mechanical Characteristics
u EIAJ SC70-5L package
u Molding compound flammability rating: UL 94V-0
u Marking : 701
u Packaging : Tape and Reel per EIA 481
Applications
u Cell phone handsets
u Cell phone accessories
u RF Communications equipment
u Laptop Computers
u Two-way pagers
u GPS Devices
Circuit Diagram Schematic & PIN Configuration
SC70-5L (Top View)
Revision 9/2000
1
www.semtech.com
PROTECTION PRODUCTS
Absolute Maximum Rating
STF701
gnitaRlobmySeulaVstinU
rewoPetatS-ydaetSP
erutarepmeTgniredloSdaeLT
erutarepmeTgnitarepOT
erutarepmeTegarotST
Electrical Characteristics
107FTS
retemaraPlobmySsnoitidnoCmuminiMlacipyTmumixaMstinU
egatloVffO-dnatSesreveRSVTV
egatloVnwodkaerBesreveRSVTV
tnerruCegakaeLesreveRSVTI
tnerruCegakaeLesreveRSVTI
kp
2-4-00016CEIrepegrahcsiDriADSEV
2-4-00016CEIrepegrahcsiDtcatnoCDSEV
MWR
I
RB
R
R
V
MWR
V
MWR
Am1=6 V
t
C°52=T,V5=5Aµ
PP
PP
L
J
GTS
C°52=T,V3.3=1Aµ
001Wm
51Vk
8Vk
).ces01(062C°
521+ot02-C°
051+ot55-C°
5V
ecnaticapaCnoitcnuJSVTC
j
dnasnipO/IneewteB
56V
ecivedhcae,dnG
V
R
zHM1=f,V0=
ecnatsiseRseireSlatoTReniLhcaE540555
roticapaCCeniLhcaE001Fp
ecnaticapaClatoTC
TOT
dnatupnIneewteB
032Fp
eniLhcae,tuptuO
V
R
zHM1=f,V0=
W
2ã 2000 Semtech Corp.
www.semtech.com
PROTECTION PRODUCTS
PROTECTION PRODUCTS
Typical Characteristics
STF701
Normalized Breakdown Voltage vs. Temperature
1.1
1.05
1
|VBR|
0.95
0.9
-40 10 60 110
Temperature (
O
C)
Typical Insertion Loss
Normalized Resistance vs. Temperature
1.1
1.05
1
|R|
0.95
0.9
-40 10 60 110
Temperature (
O
C)
ESD Clamping
(8kV Contact per IEC 61000-4-2)
ycneuqerFnoitaunettA
zHM001Bd57.01-
zHG1Bd17.41-
Measurement taken with Hewlett Packard Model
8753E Network Analyzer
ã 2000 Semtech Corp.
3
www.semtech.com
PROTECTION PRODUCTS
Applications Information
STF701
Device Connection for Protection of Two Data Lines
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.
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 (V
) given by:
C1
Figure 1 - STF701 Circuit Diagram
Figure 2 - STF701 Connection Diagram
VC1 = Vbr + RD * I
PP
where
Vbr = Breakdown voltage of the TVS
RD = Dynamic resistance of the TVS
IPP = Peak pulse (ESD) current
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.
Figure 3 - STF701 Clamping Characteristics
4ã 2000 Semtech Corp.
www.semtech.com
PROTECTION PRODUCTS
PROTECTION PRODUCTS
Outline Drawing - SC70-5L
STF701
Land Pattern - SC70-5L
ã 2000 Semtech Corp.
5
www.semtech.com
PROTECTION PRODUCTS
Marking Codes
STF701
rebmuNtraP
107FTS1F
edoC
Ordering Information
rebmuNtraP
CT.107FTSV5000,3hcnI7
GT.107FTSV5000,01hcnI31
gnikraM
gnikroW
egatloV
leeRrepytQeziSleeR
Contact Information
Semtech Corporation
Protection Products Division
652 Mitchell Rd., Newbury Park, CA 91320
Phone: (805)498-2111 FAX (805)498-3804
6ã 2000 Semtech Corp.
www.semtech.com
Loading...