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VBUS054B-HSF-GS08

P1-P3P4-P6P7-P9
VBUS054B-HSF
www.vishay.com
Vishay Semiconductors
Rev. 1.7, 15-Jul-15
4
Document Number: 81624
For technical questions, contact: ESDprotection@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
Fig. 9 - Typical Peak Clamping Voltage at ESD
Contact Discharge (acc. IEC 61000-4-2)
Fig. 10 - Typical Peak Clamping Voltage at ESD
Contact Discharge (acc. IEC 61000-4-2)
APPLICATION NOTE
With the VBUS054B-HSF a double, high speed USB-port or up to 4 other high speed signal or data lines can be protected
against transient voltage signals. Negative transients will be clamped close below the ground level while positive transients will
be clamped close above the 5 V working range. An avalanche diode clamps the supply line (V
BUS
at pin 5) to ground (pin 2). The
high speed data lines, D
1+
, D
2+
, D
1-
and D
2-
, are connected to pin 1, 3, 4 and 6. As long as the signal voltage on the data lines
is between the ground- and the V
BUS
-level, the low capacitance PN-diodes offer a very high isolation to V
BUS
, ground and to
the other data lines. But as soon as any transient signal exceeds this working range, one of the PN-diodes starts working in the
forward mode and clamps the transient to ground or to the avalanche breakthrough voltage level of the Z-diode between pin 5
and pin 2.
- 250
- 200
- 150
- 100
- 50
0
50
100
150
200
0 5 10 15 20
V
ESD
(kV)
V
C-ESD
(V)
acc. IEC 61000-4-2
contact discharge
V
C-ESD
Pin 1, 3, 4 or 6 to Pin 2
Pin 2 to Pin 1, 3, 4 or 6
20555
- 80
- 60
- 40
- 20
0
20
40
60
80
100
120
140
0 5 10 15 20
V
ESD
(kV)
V
C-ESD
(V)
acc. IEC 61000-4-2
contact discharge
V
C-ESD
Pin 5 to Pin 2
Pin 2 to Pin 5
20556
R
E
C
E
I
V
E
R
IC
20399
6
4
5
1
2
3
t
i
w
n
U
S
B
-
P
o
r
t
V
BUS
D
1+
D
1-
D
2+
D
2-
G
ND
VBUS054B-HSF
www.vishay.com
Vishay Semiconductors
Rev. 1.7, 15-Jul-15
5
Document Number: 81624
For technical questions, contact: ESDprotection@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
BACKGROUND KNOWLEDGE:
A Zener- or avalanche diode is an ideal device for “cutting” or “clamping” voltage spikes or voltage transients down to low and
uncritical voltage values. The breakthrough voltage can easily be adjusted by the chip-technology to any desired value within a
wide range. Up to about 6 V the “zener-effect” (tunnel-effect) is responsible for the breakthrough characteristic. Above 6 V the
so-called “avalanche-effect” is responsible. This is a more abrupt breakthrough phenomenon. Because of the typical “Z-shape”
of the current-voltage-curve of such diodes, these diodes are generally called “Z-diode” (= zener or avalanche diodes). An
equally important parameter for a protection diode is the ESD- and surge-power that allows the diode to short current in the
pulse to ground without being destroyed.
This requirement can be adjusted by the size of the silicon chip (crystal). The bigger the active area the higher the current that
the diode can short to ground.
But the active area is also responsible for the diode capacitance - the bigger the area the higher the capacitance.
The dilemma is that a lot of applications require an effective protection against more then 8 kV ESD while the capacitance must
be lower then 5 pF! This is well out of the normal range of a Z-diode. However, a protection diode with a low capacitance
PN-diode (switching diode or junction diode) in series with a Z-diode, can fulfil both requirements simultaneously: low
capacitance AND high ESD- and/or surge immunity become possible!
A small signal (V
pp
< 100 mV) just sees the low capacitance of the PN-diode, while the big capacitance of the Z-diode in series
remains “invisible”.
Such a constellation with a Z-diode and a small PN-diode
(with low capacitance) in series (anti-serial) is a real
unidirectional protection device. The clamping current can
only flow in one direction (forward) in the PN-diode. The
reverse path is blocked.
Another PN-diode "opens" the back path so that the
protection device becomes bidirectional! Because the
clamping voltage levels in forward and reverse directions
are different, such a protection device has a Bidirectional
and Asymmetrical clamping behaviour (BiAs) just like a
single Z-diode.

D
ZD
20400
C
TOT
C
D
= 0.4 pF
C
ZD
= 110 pF
20404
ZD
I/O
G
nd
D
1
D
2
VBUS054B-HSF
www.vishay.com
Vishay Semiconductors
Rev. 1.7, 15-Jul-15
6
Document Number: 81624
For technical questions, contact: ESDprotection@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
One mode of use is,…
in the very first moment before any pulses have arrived, all
three diodes are completely discharged (so the diode
capacitances are empty of charge) the first signal pulse with
an amplitude > 0.5 V will drive the upper PN-diode (D
1
) in a
forward direction and “sees” the empty capacitance of the
Z-diode (ZD).
Depending on the duration of this pulse and the pause to the
next one the Z-diodes capacitance can be charged up so
that the next pulse “sees” a lower capacitance. After some
pulses the big Z-diode could be completely charged up so
that the following pulses just see the small capacitance of
both PN-diodes.
For some application this can work perfectly.....
For others applications the capacitance must be the same
all the time from the first till the last pulse.
For these applications the appropriate mode of use is to
connect the Z-diode to the supply voltage.
In this mode the Z-diode is charged up immediately by the
supply voltage and both PN-diodes are always used in
reverse. This keeps their capacitance at a minimum.
20405
ZD
I/O
G
nd
D
1
D
2
ZD
I/O
G
nd
20406
V
BUS
D
1
D
2
P1-P3P4-P6P7-P9

VBUS054B-HSF-GS08

Mfr. #:
Buy VBUS054B-HSF-GS08
Manufacturer:
Vishay Semiconductors
Description:
TVS Diodes / ESD Suppressors 5.0 Volt 45 Watt for 4-Line USB Ports
Lifecycle:
New from this manufacturer.
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