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For a high-speed interface, an ESD diode supplier must provide complete capacitance, package, polarity and test-condition data that can be checked on the target board.
Direct answer
Check the interface voltage, data rate, channel count and downstream withstand voltage first. Then compare Cj, leakage, clamping behavior, package parasitics, pin assignment and the supplier’s current datasheet before sample testing.
The supplier check starts with the interface
“Low capacitance” is a screening condition, not a final result. The connector, trace, package and return path form one electrical channel. For USB, display, sensor and industrial communication lines, the candidate must also match polarity, common-mode range and channel arrangement.
normal signal range and rate
single-ended or differential topology
number of protected channels
maximum allowed downstream voltage
Evidence fields for an ESD part
| Field | Why it matters |
|---|---|
| Cj | Adds load to the signal channel; test frequency and bias must be known |
| VC | Must be read with the specified current and waveform |
| Leakage | Can affect bias and idle power |
| Package and pinout | Changes parasitics and routing length |
| ESD test rating | Describes the stated component test, not automatic system compliance |
Use current ASIM datasheets as the reference point
ASIM ESD3V3D500TA and ESD5D150TA datasheets show how voltage, clamping, capacitance, package and test conditions are presented together. The numbers are part-specific and should not be transferred to another model without checking its own revision. The product center and download center are useful for locating the relevant package family and the latest available document.
Board-level verification
Place the device close to the entry point and keep the return path short.
Measure the protected node and the interface waveform with the actual package and land pattern.
Run normal function, signal-integrity and the approved ESD test plan.
Record the exact part number, datasheet revision and board revision.
Frequently Asked Questions
Is the lowest Cj supplier always the best choice?
No. Cj must be balanced with VRWM, leakage, clamping, pinout, package parasitics and the system test result.
Does a component ESD rating prove system compliance?
No. System compliance depends on the product construction, layout, return path and the approved test plan.
Data source
Data verification date: October 12, 2026. Specific models, test levels, and rectification conclusions are subject to the current specifications, applicable standards, and the approved verification plan.
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