MLV Selection and Applications

Technical Topic 01

A practical MLV selection process begins with the protected node and the normal signal or power conditions. It then connects working voltage, capacitance, varistor voltage, clamping behavior, pulse conditions and package constraints to a validation plan.

Do not begin with a single clamping-voltage number. Values are comparable only when test current, waveform, polarity, temperature and measurement method are compatible.

Recommended reading sequence

The sequence is designed to prevent a package match or one favorable number from becoming an unsupported replacement decision.

01 Define

MLV terminology and product boundaries

Separate ceramic multilayer varistors from molded SMD MOVs, disc MOVs, polymer suppressors and TVS diodes before comparing data.

02 Explain

How multilayer varistors work

Review the transition from high-impedance operation to nonlinear conduction and understand why recovery, leakage and pulse stress remain part of the design question.

03 Compare

Datasheet parameters and test conditions

Keep maximum continuous voltage, varistor voltage, clamping voltage, capacitance and surge claims attached to their definitions and measurement conditions.

04 Select

A practical MLV selection workflow

Translate the circuit requirement into an auditable shortlist, then record the assumptions and evidence that still need confirmation.

05 Apply

Application paths

Review interface-specific trade-offs for USB, CAN, LIN, industrial I/O, power rails and other protected nodes instead of treating every transient as the same event.

Selection inputs

Record the maximum normal voltage, interface bandwidth, source impedance, allowed leakage and capacitance, transient standard and level, pulse repetition, ambient and component temperature, package limits and qualification requirements. Missing inputs should remain visible as open questions.

Validation outputs

The result is not merely a part number. It is a controlled comparison, a PCB placement decision, a test plan and evidence that the selected part meets functional, reliability and compliance requirements in the target system.

A lower nominal clamping value is not automatically better. Protection margin, current at the protected node, signal integrity, device tolerance and energy handling must be evaluated together.