ZXY-B2111 Audio Isolation Transformer, 1:1 600 Ohm Line Audio Transformer, SMD Potting, 4.6 kV Withstanding Voltage

1. Product Name

ZXY-B2111, 1:1 600 Ω audio isolation transformer: ED8×11 nickel-steel laminated core, 0.15 mm PC-grade laminations interleaved and fully stacked, two windings each of 520 turns of 2UEW-F Ø0.04 mm magnet wire, thickened two-slot bobbin, black high-temperature resistant housing fully potted. Six SMD gull-wing leads, three per row. Body max 13.8 mm × 10.6 mm, height max 8.0 mm.

Two faces, one solid body. One face carries the six terminals and the potted winding; the other is a flat molded wall. Because the fill compound is inside the housing, the part is a sealed unit externally and the winding is never exposed to handling, cleaning, or reflow.

2. Construction and Materials

Core. ED8×11 nickel-steel laminations, 0.15 mm thick, PC grade, interleaved and fully stacked. Nickel steel is used because at the low end of the audio band, a stacked nickel-iron core saturates later than ferrite in the same volume, allowing this product to maintain 1.4 H inductance and stay within ±0.25 dB at 200 Hz. The thin foil keeps eddy-current loss small at this frequency, and interleaving joins the two halves of the magnetic path with multiple overlapping joints rather than a single butt joint.

Two details that set the ratings. The isolation barrier is the dividing wall between the two winding sections and is the reason for the 4,600 VDC withstand rating: the bobbin is thickened and split into two sections, and the windings are separated by molded material plus fill compound rather than tape alone. The leads are formed gull-wing structures, making this a reflow-compatible component; the recommended temperature profile peaks at 260 °C, and the housing has been heat-tested to 280 °C.

Sealing. Epoxy covers the winding face and stops before the solderable portion of the leads. This boundary is deliberate: the fill must cover the coil to seal and lock the core, but it must not creep onto the terminals, because resin on the leads would prevent proper wetting in the oven.

Both windings are 520 turns of 2UEW-F Ø0.04 mm magnet wire. Equal turns and equal windings make the two sides interchangeable and hold the turns ratio within ±1 %. The specification also adds a process requirement that windings must be wound evenly, because a scrambled winding adds wire length and pushes DC resistance outside the ±10 % window.

3. Features

Matched 1:1 windings. Both windings are 520 turns of the same wire on the same bobbin, and the turns ratio is held within ±1 % when measured at 15 kHz, 1 V across pins 1-3 and 4-6. Equal turns and equal windings let this part serve as a balanced line isolator rather than a ratio-changing device.

ED8×11 nickel-steel laminated core. The core is fully stacked from 0.15 mm PC-grade nickel-steel laminations with interleaved assembly. Interleaving alternates the orientation of adjacent laminations so that the joints between the two halves of the stack do not align in the same plane, and full stacking leaves no air gap in the magnetic path.

Thickened two-slot bobbin. The bobbin is divided into two sections and thickened, physically separating the two windings and providing the wall thickness on which the 4,600 VDC withstand rating depends.

Fully potted housing. The body is a black high-temperature resistant housing with the core and windings potted inside. The fill compound keeps the assembly rigid, keeps moisture away from the windings, and prevents the core from shifting inside the housing during handling and reflow.

Six SMD gull-wing terminals. Three leads per row, formed as gull wings, allow this part to be placed and reflowed together with the rest of the board. The recommended reflow profile peaks at 260 °C, and the housing has been heat-tested to 280 °C.

4. Advantages

Flat response in the specified band. Referenced to 2 kHz, response is held within ±0.25 dB from 200 Hz to 4 kHz. In a 600 Ω line, this is precisely what keeps the transformer from coloring the signal it carries, which is the entire purpose of installing an isolation transformer.

Return loss in a 600 Ω system. Minimum 24 dB over the same band means the device looks close to 600 Ω on both sides, so little energy is reflected back into the line and no ripple from impedance mismatch appears.

Low insertion loss. Maximum 2 dB at 2 kHz with the secondary terminated in 412 Ω. A transformer with less loss requires less make-up gain downstream, and less gain means less noise added to the signal.

Dielectric strength stated as a tested value. 4,600 VDC is applied between secondary and primary for 60 s at a 1 mA leakage limit, and insulation resistance is minimum 100 MΩ at 200 VDC. Both are acceptance items on every unit, not type-test declarations.

Compact potted body for dense boards. Measuring 13.8 mm × 10.6 mm with 8.0 mm height, six leads on 5 mm in-row spacing and 11.0 mm between rows, the pad footprint is rectangular and the layout can be planned in advance rather than treated as a through-hole part that must be hand-placed.

5. Applications

Inter-stage line isolation in audio equipment. When two stages in the same chassis sit at different ground potentials, a 1:1 transformer can carry the signal across without tying the two grounds together.

Isolation between pieces of equipment. Between two devices on a 600 Ω reference line, this part breaks the ground loop that would otherwise appear as hum, while preserving level on both sides of the break.

Signal transmission from 200 Hz to 4 kHz. The specified band covers voice and program material, and the ±0.25 dB window is calibrated over that band rather than the full audio range.

Where galvanic isolation must be proven. When the design must demonstrate isolation between windings, the 4,600 VDC withstand and 100 MΩ insulation resistance are the two figures a test house will ask for.

In the signal chain, the device sits between the source and the next stage, carrying the signal across the isolation barrier without connecting the two grounds. Level and response should not change.

6. Specifications

The following data is the approved specification of the ZXY-B2111, reproduced as stated.

6.1 General

6.2 Electrical Parameters

6.3 Mechanical Dimensions and Pad Footprint

6.4 Construction

6.5 Quality and Testing

7. Ordering Information

This product is ordered under the model designation ZXY-B2111. The core, bobbin, and housing are fixed parts of the design; windings, turns ratio, and lead arrangement can be customized to customer drawings for applications where the standard 600 Ω 1:1 configuration does not match the equipment requirement. If the construction changes, specify the turns ratio and impedance when ordering so the corresponding acceptance sheet can be included with the shipment.

Brand/Manufacturer: ZXY, Shenzhen ZhiXiangYuan Electronics Co., Ltd. http://www.zxycoil.com