STE Introduces 3225 and 4032 SMD Varistors for Compact Protection Circuits

Chongdiantou reported on April 29, 2025 that STE had introduced surface mount varistors in 3225 and 4032 packages. The announcement addressed demand for compact protection components in LED products, industrial equipment, communications devices, household appliances and power adapters.

The report presented the range as an extension of STE's capacitor, varistor and thermistor portfolio. Its main product themes were a smaller mounting outline, compatibility with automated assembly and transient-overvoltage protection. This English adaptation preserves the reported product information while separating announcement values from the conditions required for component selection.

Two packages in the reported range

A varistor has a nonlinear voltage-current characteristic. It carries relatively little current within its intended normal operating conditions and conducts more strongly during an overvoltage event. The voltage remaining across it depends on the current and waveform, so its nominal varistor voltage must not be treated as a fixed clamping voltage.

Chongdiantou gave the following comparison for the two STE packages:

These are historical values from the linked report. Use the part-specific STE SMD-MOV specification for design selection. The accompanying product tables specify an 8/20 µs waveform for peak current and a 10/1000 µs waveform for energy. Pulse-count conditions are part-specific and must be read with each table entry. These figures are not continuous current limits.

Likewise, the 200–820 V range describes nominal varistor voltage, not the allowable continuous AC supply range. A design decision needs the selected device's maximum continuous voltage, clamping data and temperature limits together. The reported package dimensions also do not replace a toleranced terminal and land-pattern drawing.

Assembly and packaging details

The announcement described molding material meeting UL94 V-0 and suitability for the specified lead-free reflow or wave-soldering processes. A material flammability classification is distinct from certification of the complete component or the equipment containing it.

The packaging figures were specific: 3225 devices used 16 mm carrier tape, while 4032 devices used 24 mm tape. Both were supplied in reels of 1500 pieces. The reported carton configurations were 11 reels, or 16,500 pieces, for 3225 and six reels, or 9000 pieces, for 4032.

Those formats support automated feeding and placement. Production benefits depend on the actual footprint, soldering profile and assembly controls; the report does not provide a measured comparison of manufacturing yield or cost.

Applications depend on the protection circuit

Chongdiantou highlighted power adapters, lighting and industrial or communications electronics as potential uses. It also referred to temperature and humidity performance and reliability testing. The linked report can be consulted for its original illustrations, but the available text does not establish a complete qualification record or automotive approval for the range.

For an intended application, the next step is to obtain the current specification for the exact SMD variant and review it alongside the required equipment surge test, downstream voltage tolerance and fault protection. A successful component test under defined conditions is useful evidence; it does not, by itself, establish the surge performance of the complete product.

Figures and tables from the original report

The following figures retain their original captions, markings and historical context. Transcribed tables present the values shown in the published images; product selection should use the specifications for the selected part.

These are statements in the historical source image, not independent verification of certification, environmental testing or automotive qualification. Check the specific device soldering profile before assembly.

The source first-column heading reads “product storage”; the English heading is normalized to Parameter. Historical image: revision 2024-11-14, page 4.

Historical revision 2024-11-14. The source gives 190 V AC for 3225K301K and 195 V AC for 4032K301K; the 621 models have clamping values of 1025 V and 1020 V respectively. These differences are retained.

Historical revision 2024-11-14. The source gives 190 V AC for 3225K301K and 195 V AC for 4032K301K; the 621 models have clamping values of 1025 V and 1020 V respectively. These differences are retained. The 781K row prints 3500 × 2 pulses, unlike 3500 × 1 pulse in the other rows. This source anomaly is retained and does not establish a verified two-pulse rating.

Standard references and the two vibration-amplitude statements are retained as printed; they are not verification of current standards or certification. The English humidity wording supplies the percent meaning missing from clause b in the image.

Related reading cited by the original report

Chinese source titles are retained below. 正浩、隆鑫两家知名户外电源品牌齐选松田元件 松田电子推出贴片式NTC热敏电阻器，可用于消费电子、工业设备等领域实现产品小型化 百款设备的共同选择，一文看懂松田元件历年拆解案例