TVS Diode Array
For ESD and Latch-Up Protection
PROTECTION PRODUCTS
Description
The SMF series TVS arrays are designed to protect sen-
sitive electronics from damage or latch-up due to ESD
and other voltage-induced transient events. They are
designed for use in applications where board space is at
a premium. Each device will protect up to four lines.
They are unidirectional devices and may be used on lines
where the signal polarities are above ground.
TVS diodes are solid-state devices designed specifically
for transient suppression. They feature large cross-sec-
tional area junctions for conducting high transient cur-
rents. They offer desirable characteristics for board level
protection including fast response time, low operating
and clamping voltage, and no device degradation.
The SMF series devices may be used to meet the immu-
nity requirements of IEC 61000-4-2, level 4. The small
SC70 package makes them ideal for use in portable elec-
tronics such as cell phones, PDA’s, notebook comput-
ers, and digital cameras.
SMF05 and SMF12
Features
Transient protection for data lines to
IEC 61000-4-2 (ESD) ±15kV (air), ±8kV (contact)
IEC 61000-4-4 (EFT) 40A (5/50ns)
Small package for use in portable electronics
Protects four I/O lines
Working voltage: 5V and 12V
Low leakage current
Low operating and clamping voltages
Solid-state silicon-avalanche technology
Mechanical Characteristics
EIAJ SC70-5L package
Molding compound flammability rating: UL 94V-0
Marking : Marking Code
Packaging : Tape and Reel
Applications
Cellular Handsets and Accessories
Cordless Phones
Personal Digital Assistants (PDA’s)
Notebooks & Handhelds
Portable Instrumentation
Digital Cameras
Peripherals
MP3 Players
Circuit Diagram
1
3
4
5
Schematic & PIN Configuration
1
2
3
5
4
2
SC70-5L (Top View)
Revision 01/22/08
1
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SMF05 and SMF12
PROTECTION PRODUCTS
Absolute Maximum Rating
Rating
Peak Pulse Power (tp = 8/20
µ
s)
Peak Forward Voltage (I
F
= 1A, tp=8/20
µ
s)
ESD per IEC 61000-4-2 (Air)
ESD per IEC 61000-4-2 (Contact)
Lead Soldering Temperature
Operating Temperature
Storage Temperature
Symbol
P
pk
V
FP
V
ESD
T
L
T
J
T
STG
Value
200
1.5
20
15
260 (10 seconds)
-55 to +125
-55 to +150
Units
Watts
V
kV
o
C
C
C
o
o
Electrical Characteristics
SMF05
Par ame te r
Reverse Stand-Off Voltage
Reverse Breakdown Voltage
Reverse Leakage Current
Clamp ing Voltage
Clamp ing Voltage
Peak Pulse Current
Junction Cap acitance
Symbo l
V
RWM
V
BR
I
R
V
C
V
C
I
P P
C
j
I
t
= 1mA
V
RWM
= 5V, T=25°C
I
PP
= 1A, t
p
= 8/20µ s
I
PP
= 12A, t
p
= 8/20µ s
t
p
= 8/20µ s
Between I/O p ins and
Ground
V
R
= 0V, f = 1MHz
150
6
10
9.5
12.5
12
175
Co nditio ns
Minimum
Typical
Maximum
5
Units
V
V
µA
V
V
A
pF
SMF12
Par ame te r
Reverse Stand-Off Voltage
Reverse Breakdown Voltage
Reverse Leakage Current
Clamp ing Voltage
Clamp ing Voltage
Peak Pulse Current
Junction Cap acitance
Symbo l
V
RWM
V
BR
I
R
V
C
V
C
I
P P
C
j
I
t
= 1mA
V
RWM
= 12V, T=25°C
I
PP
= 1A, t
p
= 8/20µ s
I
PP
= 8A, t
p
= 8/20µ s
t
p
= 8/20µ s
Between I/O p ins and
Ground
V
R
= 0V, f = 1MHz
2
Co nditio ns
Minimum
Typical
Maximum
12
Units
V
V
13.3
1
19
25
8
60
75
µA
V
V
A
pF
2008 Semtech Corp.
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SMF05 and SMF12
PROTECTION PRODUCTS
Typical Characteristics
Non-Repetitive Peak Pulse Power vs. Pulse Time
10
Peak Pulse Power - P
pk
(kW)
Power Derating Curve
110
100
90
% of Rated Power or I
PP
80
70
60
50
40
30
20
10
1
0.1
0.01
0.1
1
10
Pulse Duration - t
p
(µs)
100
1000
0
0
25
50
75
100
o
125
150
Ambient Temperature - T
A
( C)
Pulse Waveform
110
100
90
80
Percent of I
PP
70
60
50
40
30
20
10
0
0
5
10
15
Time (µs)
20
25
30
td = I
PP
/2
e
-t
Clamping Voltage vs. Peak Pulse Current
30
Waveform
Parameters:
tr = 8µs
td = 20µs
25
20
SMF12
15
10
5
0
0
2
4
6
8
10
12
14
Peak Pulse Current - I
PP
(A)
Waveform
Parameters:
tr = 8µs
td = 20µs
SMF05
Clamping Voltage - V
C
(V)
Capacitance vs. Reverse Voltage
160
140
Capacitance - C
j
(pF)
120
100
80
60
40
20
f = 1MHz
0
0
1
2
3
4
5
6
Reverse Voltage - V
R
(V)
SMF05
SMF05 Insertion Loss S21
CH1 S21
LOG
6 dB / REF 0 dB
START . 030 MHz
.
STOP 3000 000000 MHz
2008 Semtech Corp.
3
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SMF05 and SMF12
PROTECTION PRODUCTS
Typical Characteristics (Continued)
SMF05 ESD Clamping
(8kV Contact per IEC 61000-4-2)
SMF12 ESD Clamping
(8kV Contact per IEC 61000-4-2)
2008 Semtech Corp.
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SMF05 and SMF12
PROTECTION PRODUCTS
Applications Information
Device Connection for Protection of Four Data Lines
The SMFxx is designed to protect up to four unidirec-
tional data lines. The device is connected as follows:
1. Unidirectional protection of four I/O lines is
achieved by connecting pins 1, 3, 4, and 5 to the
data lines. 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.
Circuit Board Layout Recommendations for Suppres-
sion of ESD.
Good circuit board layout is critical for the suppression
of ESD induced transients. The following guidelines are
recommended:
Place the SMFxx near the input terminals or con-
nectors to restrict transient coupling.
Minimize the path length between the SMFxx and
the protected line.
Minimize all conductive loops including power and
ground loops.
The ESD transient return path to ground should be
kept as short as possible.
Never run critical signals near board edges.
Use ground planes whenever possible.
Matte Tin Lead Finish
Matte tin has become the industry standard lead-free
replacement for SnPb lead finishes. A matte tin finish
is composed of 100% tin solder with large grains.
Since the solder volume on the leads is small com-
pared to the solder paste volume that is placed on the
land pattern of the PCB, the reflow profile will be
determined by the requirements of the solder paste.
Therefore, these devices are compatible with both
lead-free and SnPb assembly techniques. In addition,
unlike other lead-free compositions, matte tin does not
have any added alloys that can cause degradation of
the solder joint.
SMF Circuit Diagram
1
3
4
5
2
Protection of Four Unidirectional Lines
2008 Semtech Corp.
5
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