Standoff voltage
The highest voltage the device tolerates without conducting. Set it above the normal working voltage including ripple, or the part leaks in service.
Protective Component products
Bidirectional ESD Protection Diodes
Bidirectional ESD parts clamp symmetrically, which differential pairs need because the signal swings either side of the common mode point. Channel to channel capacitance matching matters as much as the absolute value on a fast link.
Part number search & selector
Find Bidirectional ESD Protection Diodes part numbers
The table uses the current English-site product records, published selection fields and part-specific technical-file links.
* Frozen Image and Part Number columns · drag horizontally to review all specifications
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Polarity
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Vesd Air/Vesd Contact
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| Image | Part number | Datasheet | Compare | Downloads | Polarity | Vrwm/V | Vesd Air/Vesd Contact | Cj/pf | Package | Operating Temperature | Sample |
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WHALD30E2B | SPEC | Bi-Directional ESD | 30 | ±30KV/±30KV | 0.9 | SOT-23 | -40 °C to 125 °C |
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By polarity
Unidirectional and bidirectional devices
Polarity follows the signal: unidirectional for DC rails, bidirectional for AC and differential lines.
How to select
Selecting a TVS or ESD device in four steps
Threat first, then polarity, then the voltage window, then capacitance.
- 01
Identify the threat
Surge energy from lightning or switching needs a TVS. Fast human-body or contact discharge on a data port needs a low capacitance ESD device.
- 02
Choose the polarity
Unidirectional suits single-polarity DC rails. Bidirectional suits AC lines and differential pairs that swing both sides of ground.
- 03
Set the voltage window
Standoff voltage above the highest normal working voltage, clamping voltage below what the protected device survives. Both have to hold.
- 04
Check capacitance
On high speed lines, capacitance decides whether the protection is usable. Measure the eye diagram and return loss after fitting.
Parameters
Reading TVS and ESD ratings
Standoff and clamping voltage form a window that both has to fit inside.
Breakdown voltage
Where conduction begins, measured at a small stated test current. It sits above the standoff figure and below the clamping voltage.
Clamping voltage
The voltage across the device while it diverts a stated peak current. This is what the protected circuit actually sees, so compare at the same current.
Peak pulse power
Energy handling at a stated waveform, commonly 8 by 20 or 10 by 1000 microseconds. The waveform must match or the figures do not compare.
Capacitance
The load the device places on the line. Low capacitance parts exist specifically so high speed signals are not degraded by the protection.
Polarity
Unidirectional conducts hard in one direction only. Bidirectional behaves symmetrically, which is required where the signal swings both ways.
Compare
TVS against ESD devices and other protection
Energy handling, response speed and capacitance separate the choices.
Return to the selector ↑| Polarity | Parts | Vrwm/V | Vesd Air/Vesd Contact | Cj/pf | Package | Operating Temperature | Action |
|---|---|---|---|---|---|---|---|
| Bi-Directional TVS | 1 | 58 | - | - | DO-214AB | -60 °C to 150 °C | Filter → |
| ESD | 3 | 3.3, 5 | ±15KV/±12KV, ±20KV/±20KV, ±30KV/±30KV | 0.3, 0.8, 1.2 | SOD323, SOT-363, DFN2510-10L | -40 °C to 125 °C | Filter → |
| Bi-Directional ESD | 1 | 30 | ±30KV/±30KV | 0.9 | SOT-23 | -40 °C to 125 °C | Filter → |
Application review
Where TVS and ESD devices are fitted
Confirm the port type, the standard to be met and the signal speed on that line.
USB and high speed data ports
- Capacitance decides usability here. Choose a low capacitance ESD part and verify the eye diagram and return loss after fitting.
Ethernet interfaces
- Confirm how the device interacts with the magnetics already in the path, then check the clamping figure against the transceiver rating.
DC power rails
- Unidirectional parts suit single polarity rails. Set standoff above worst-case rail voltage including ripple and transients.
Industrial and automotive buses
- Buses swing both sides of ground, so bidirectional parts are usually required. Confirm the common mode range the bus specifies.
Documents
TVS and ESD datasheets
Datasheets carry the clamping curve, pulse waveform conditions and capacitance.
Showing representative available file sets. Search to find a specific SKU.
WHALD30E2BBi-Directional ESD
- 1
- PDF datasheets listed
- 0
- 3D file sets listed
- 0
- PCB footprints listed
VOOHU’s published product content is reviewed by its engineering team. Specifications, downloads and technical support information are tied to specific part numbers, so you can verify them before requesting samples or a quotation.
Category overview
TVS or ESD device, and which way round
Two decisions cover most of this category: which technology matches the threat, and whether the part needs to be unidirectional or bidirectional.
Discuss a new design
Contact FAE for a replacement assessment.
Already have a part number? Request samples or a quote.
Different events, different parts
A TVS diode is sized for surge energy from lightning coupling or heavy switching, rated in peak pulse power at a defined waveform. An ESD device is sized for fast, low energy static discharge and built for very low capacitance, so it can sit on a high speed line. Sizing one against the other threat gives the wrong part.
Polarity follows the signal
A unidirectional device conducts hard one way and blocks the other, which suits a DC rail that never goes negative. A bidirectional device is symmetric, which AC lines, differential pairs and buses swinging both sides of ground require. Fit a unidirectional part there and it conducts on the negative half.
Capacitance is the limit on fast lines
The device sits in parallel with the signal, so its capacitance is a load the line has to drive. On a high speed pair, a few picofarads visibly degrades the eye and raises return loss. That is why low capacitance ESD parts are a separate category, and why the eye should be measured with the part fitted.
FAQ
TVS and ESD questions engineers ask
Answers cover TVS against ESD, polarity choice, capacitance and placement.
Why do differential pairs use bidirectional ESD parts?
Because each line of the pair swings both above and below the common mode level. A unidirectional device would conduct on the negative excursion and distort the signal. A bidirectional device stays high impedance across the full swing and only conducts when a discharge takes the line outside the normal range.
Does the device affect the differential signal?
It adds some capacitive load. On a fast pair that shows as insertion loss and a smaller eye. What matters as much as the absolute capacitance is how well matched the two channels are, because a mismatch converts common mode noise into differential noise that lands directly on the signal.
Should I use a multi-channel array or single parts?
An array saves board area, simplifies routing and usually gives better channel matching because the channels are on one die. Single devices allow each one to sit right at its own connector pin. Choose on the number of lines, the space available and how critical matching is.
How does this differ from a bidirectional TVS?
Both clamp symmetrically, but an ESD part is built for low capacitance and fast response against static discharge, while a TVS is sized for surge energy. On a high speed pair the ESD part is usually the right choice; where both threats exist, the two are sometimes combined in stages.
How do I request samples or a quote?
With a complete part number, send the part number, quantity, delivery region and the date you need it. If you are still selecting, send the interface type, the data rate, the number of lines and the discharge level you must withstand.
Engineer support
Continue after product selection
Send the candidate part number and the condition you need reviewed. Sample support can be added after the selection is clear; commercial questions may be discussed in the same engineering conversation.
- 1Selected part numbers
- 2Engineering review
- 3Sample request
- 4Commercial discussion
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Samples are free of charge. Sample quantity and lead time depend on the part number and project stage. Sales will respond on business days.
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