nup2201 ON Semiconductor, nup2201 Datasheet - Page 4

• Manufacturer Part Number: nup2201
• Description: Low Capacitance Tsop-6 Diode-tvs Array For High Speed Data Lines Protection
• Manufacturer: ON Semiconductor

positive ESD condition occurs, diode D1 will be forward
biased while diode D2 will be forward biased when a
negative ESD condition occurs. For slower transient
conditions, this system may be approximated as follows:
For positive pulse conditions:
For negative pulse conditions:
number of nanoseconds. Under these conditions, the effect
of parasitic inductance must be considered. A pictorial
representation of this is shown below.
transients would be:
For positive pulse conditions:
For negative pulse conditions:
only depends on the Vf of the steering diodes but also on the
L di
result in hundreds of volts appearing on the supply rail. This
endangers both the power supply and anything attached to
that rail. This highlights the importance of good board
layout. Taking care to minimize the effects of parasitic
Protected
V
Looking at the figure above, it can be seen that when a
Vc = Vcc + Vf
Vc = −Vf
ESD events can have rise times on the order of some
Protected
An approximation of the clamping voltage for these fast
Vc = Vcc + Vf + (L di
Vc = −Vf – (L di
As shown in the formulas, the clamping voltage (Vc) not
Supply
Device
CC
Power
Supply
Device
Power
ESD
/dt factor. A relatively small trace inductance can
D2
Data Line
Data Line
D1
ESD
V
/dt)
CC
ESD
D1
D2
D2
D1
/dt)
I
I
ESDpos
I
ESDneg
I
V
ESDpos
ESDneg
C
= V
I
I
V
ESDpos
ESDpos
C
CC
= −Vf − (L diESD/dt)
+ Vf + (L diESD/dt)
VF + V
CC
I
I
ESDneg
ESDneg
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−VF
NUP2201MR6
4
inductance will provide significant benefits in transient
immunity.
present when discrete diodes are used to suppress ESD
events across datalines and the supply rail. Discrete diodes
with good transient power capability will have larger die and
therefore higher capacitance. This capacitance becomes
problematic as transmission frequencies increase. Reducing
capacitance generally requires reducing die size. These
small die will have higher forward voltage characteristics at
typical ESD transient current levels. This voltage combined
with the smaller die can result in device failure.
overcome the disadvantages encountered when using
discrete diodes for ESD protection. This device integrates a
TVS diode within a network of steering diodes.
to ground through the TVS diode as shown below.
be:
Figure 4 and depends on the magnitude of the ESD current.
The steering diodes are fast switching devices with unique
forward voltage and low capacitance characteristics.
Even with good board layout, some disadvantages are still
The ON Semiconductor NUP2201MR6 was developed to
During an ESD condition, the ESD current will be driven
The resulting clamping voltage on the protected IC will
Vc = V
The clamping voltage of the TVS diode is provided in
V
Protected
CC
F
Supply
Device
Power
+ V
NUP2201MR6 Equivalent Circuit
TVS
.
Data Line
D1
D2
D3
D4
0
D1
D2
I
ESDpos