Whitepaper

What are TVS diodes and how do you
choose the right one?
Burkhard Laue - Application Marketing Manager

When it comes to medium-voltage high-energy pulses that last milliseconds,
choosing the right TVS diode can be vital. Do you have the right protection
for the typical surge events your system will face?

Optional
TVS-diodefor block A
VinInput
TVS-diode

Charger switch
or OVP

DC-DC
down-converter

Optional
OVP-output
clamping-diodeSignal lines and interfaces are designed with a specificvoltage range tolerance. Within these limits, the system
operates safely. However, when the safe operating area isexceeded, the system is vulnerable to disturbances or caneven get damaged by exposure to strong transients.
High current surge pulses originate from external surge
events through, for example, a charger or a cable, and frominternal surge events like switching events and load changes.
Discrete parallel protection solutions are necessary to shortthese surges to ground, promptly and recurrently. This blog
addresses highly robust protection diodes meant for DC-lines
or slow speed signal lines.
Transient Voltage Suppressor or TVS diodes are an effective
solution to protect other semiconductors from any damaging
surge levels they may be exposed to. Some confusion canarise as ESD diodes can often be referred to as TVS diodes inliterature. However, there is a clear distinction. TVS diodes
are particularly efficient in countering medium-voltage highenergy pulses that last milliseconds, in comparison to ESD
protection devices which address higher voltage pulses oflower energy and shorter duration.

Optional
TVS-diodefor block B

Batterypack
TVS-diode

System blockASystem blockB

Batterypack

From power lines to earphone jacks
TVS diodes are available as unidirectional and bidirectional
protection devices. The unidirectional types are perfectfor protecting power supply lines and all kinds of charger
ports. Bidirectional types can safeguard audio interfaces likeearphone jack connectors (for example in smartphones).
Nexperia’s offering includes TVS diodes for various surge
parameters including high-surge pulse ratings. Our PTVS
portfolio is designed to be placed on supply lines – and so canwithstand significantly higher energy than ESD protection
devices. TVS diodes can easily be selected by circuit operating
voltage and peak pulse power requirements.
Ultimately, package preference is a key decision factor. For
mobile and extremely space-constrained applications, types
in small packages are vital. Whereas for computing, consumer
and automotive applications, larger and more robust TVS
diodes in clip-bond technology are more common. Nexperia’s
TVS diodes help minimize PCB footprint requirements for all
applications by adjusting and optimizing the active junction
area, while ensuring good system robustness testing results.

VCL

Input waveform

Output waveform

Operation of a TVS diode on a signal line

How to choose the right solution
Choosing a TVS solution starts with context. Engineers
need to distinguish requirements between board-levelprotection and primary design protection. Further, thetypes of transients expected to impact the circuit have tobe considered – for example a lightning strike differs fromvoltage overshoots created by load change and non-perfectvoltage relation. Temperature also plays a role in finding theright device: as temperature increases, the power rating of aTVS diode decreases.
With our product selector, simply start by looking at theReverse Standoff Voltage or Reverse Working Voltage(VRWM or VWWM), which is the peak of normal DC operation
in a circuit. Typically 15% higher than this value, the Reverse
Breakdown Voltage (VBR) is the point where a TVS diodeenters low-impedance mode thanks to avalanche breakdown.
Once these two parameters are defined, review the PeakPulse Current (IPP) of the TVS for typical waveforms at
8/20 µs acc. to IEC 61000-4-5 and/or 10/1000 µs acc. to IEC
41643-21 pulse testing. Clamping Voltage (VCL) requirements
are derived from these values. When the voltage on theprotected line reaches the TVS breakdown voltage, it will
start conducting current to ground, resulting in the voltage
being clamped to VCL. To select a suitable solution, makesure the VRWM is equal to or higher than VBus, but neversurpass the VCC limits of any of the circuit’s components.

Surge pulses meet their match
With over 175 solutions in the Nexperia TVS diodes range,
our products can effectively dissipate the energy of various
forms of surge pulses. Whichever TVS solution you choose,
our devices offer reactive turn-on and low clamping,making these ideal to protect an extremely broad range ofapplications from smartphones and consumer electronics
right up to automotive electronic circuits and 600 W systems.
For further information about supply line protection with TVS
solutions, refer to our ESD application handbook, and gain adeeper understanding of TVS placement in Chapter 8.6.

About Nexperia
Nexperia is a leading expert in the high-volume
production of essential semiconductors that arerequired by every electronic design in the world.
The company’s portfolio includes diodes, bipolartransistors, ESD protection devices, MOSFETs,GaN FETs and analog & logic ICs. Headquartered in
Nijmegen, the Netherlands, Nexperia annually ships
more than 90 billion products, meeting automotivestandards. These products are recognized as
benchmarks in efficiency - in process, size, power andperformance - with industry-leading small packages
that save valuable energy and space. Nexperia has over
12,000 employees across Asia, Europe and the US.
Find your regional sales office here© 2020 Nexperia B.V.
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Date of release:
January 2020