PQ3220 High-Frequency Transformer, Low-Loss Ferrite Core, 12-Pin PCB Through-Hole Mounting, 34.5 x 36.0 x 23.0 mm, 100-500 kHz Switching Power Supply, Custom Winding

1. Product Name

PQ3220 is the core size, not a winding specification. This part is a high-frequency transformer built on a PQ3220 ferrite core, featuring twelve PCB terminals, designed for switching power supplies operating between 100 kHz and 500 kHz. As windings are custom-manufactured, the model determines the core, bobbin, pin arrangement, and outline dimensions; primary and secondary windings are wound according to the turns ratio and inductance required by the customer's circuit.

These parts are actually purchased as follows: the designer selects a core size based on power and frequency, then specifies turns, wire size, inductance, leakage inductance, and pin assignment. Therefore, the useful information to provide is the winding specification or sample, not voltage parameters; the package size is the first thing to confirm. The dimensions and pin numbering below are sufficient to complete the PCB layout before the winding is finalized.

2. Core and Construction

The core uses a low-loss ferrite material in the PQ3220 shape. The specific material grade is not designated, so it is one of the items to be negotiated when ordering. The PQ shape is designed for this type of application: two core halves form a pot structure with the winding window extending to the outer surface, allowing the coil to be wide and short, shortening the mean turn length and leaving a large area for heat dissipation. The two core halves clamp the bobbin and press against the center post; the entire assembly is held together by the frame rather than tape.

The coil is mounted on a black glass-fiber-filled bobbin, and the outer layers of the winding are wrapped with yellow high-temperature tape. The core is clamped through the bobbin window, ensuring both core halves are firmly against the center post. The base is a molded black block that carries twelve solder pins, comb-like isolation barriers between pins, and molded feet that keep the part spaced from the PCB. The yellow tape is the outer insulation of the winding; the bobbin and base use the same black molded material.

3. Dimensions and Package

Maximum outline dimensions are width 34.5 mm, depth 36.0 mm, and height 23.0 mm. The pin length below the mounting surface is 3.5 +/- 0.5 mm, and the row spacing between the two pin rows is 30.5 +/- 0.5 mm. The bottom view shows the total span of the solder pins as 30.5 +/- 0.5 mm, with 7.5 +/- 0.5 mm and 5.0 +/- 0.5 mm marked below the two groups of pins. The side view also indicates a 0.8 +/- 0.1 mm dimension for the pins.

4. Terminals and Pin Numbering

The terminals are twelve solder pins arranged in two rows of six. One row is numbered 1 to 6, the other 7 to 12, with each side divided by a center gap into groups of three plus three. The pins stand in molded comb-like barriers that separate the copper wire ends; winding leads are soldered to the bases of the pins behind the barriers. The pins are through-hole type, so the part is wave-soldered or hand-soldered from the bottom side of the PCB.

5. Operating Characteristics

The supplier publishes the operating frequency band, an efficiency ceiling, and three qualitative statements. None are accompanied by test conditions, so they are reproduced here as supplier statements rather than measured data.

6. Quality and Compliance

The compliance panel carries three statements: RoHS, UL94V-0 flame-retardant bobbin, and 100% high-voltage and insulation testing at 3.75 kV AC. No certificate numbers, standard references, or test reports are shown.

7. Features

PQ3220 low-loss ferrite core. The PQ core shape places the winding window on the outer surface, so the coil can be made wide and short, with heat dissipated over a large surface area.

Twelve-pin PCB termination. Two rows of six pins with 30.5 mm row spacing, inserted directly into through-hole pads without the need to manage flying leads.

100 kHz to 500 kHz operating band. The core and wire diameter are selected for this frequency range, which is exactly what a switching power supply of this size requires.

Yellow high-temperature tape. The winding is wrapped before installing the core, so the external insulation is tape rather than a potted housing.

UL94V-0 flame-retardant bobbin. The bobbin and frame materials are declared to meet UL94V-0, a typical entry requirement for equipment manufactured to safety standards.

Custom windings per order. Turns, wire size, inductance, leakage inductance, and pin assignment are set according to customer requirements, so the platform covers a wide range of circuit applications.

8. Advantages

High power density in a small package. The 34.5 mm x 36.0 mm x 23.0 mm size is designed for a high-power-density platform, which is why a PQ core is worth the tooling investment over EI laminated cores at these frequencies.

Fewer connection points. Through-hole pins are soldered directly to the board, eliminating lead wire assemblies, connectors, or manual dressing on the production line.

PCB layout can be finalized early. Pad layout and pin numbering are published, so the board can be laid out before the winding scheme is decided.

Every unit is insulation-tested. The supplier declares 100% high-voltage and insulation testing at 3.75 kV AC, the most critical test for switching power supply components.

One platform, multiple windings. The same core and bobbin can carry different turns and taps, so a product family can share the same pad layout.

9. Specifications

Values are transcribed from the supplier's drawing. Where not marked, "not marked" is shown; contradictions are pointed out rather than resolved.

9.1 Summary

9.2 Electrical Parameters

9.3 Mechanical Specifications

9.4 Pin Assignment

9.5 Quality and Compliance

10. Applications

The following applications are the categories listed on the supplier's application panel, along with a brief explanation of where such a device is used. They describe the market that the platform targets, not certification of this batch.

Switching power supplies. Flyback, forward, and push-pull topologies operating in this frequency band.

Photovoltaic and energy storage inverters. Auxiliary power supplies and gate drive power inside inverters and converters.

Industrial power equipment. Drive and control boards requiring isolated power rails in a compact size.

EV charging and onboard. Onboard auxiliary power supplies that need the certifications required for the application.

LED lighting drivers. Isolated constant-current stages in the same frequency band.

Medical power units. Isolated power where high-voltage test results for every unit must be documented.

11. Ordering

Please provide winding requirements rather than voltage pairs. A valid inquiry should include input and output voltage, switching frequency, power or inductance, pin assignment (if already available), whether taps or shields are needed, and quantities per order and per delivery. With this information, the core grade, wire, turns, tape, and pin arrangement can be determined, and the price follows. If the board layout is already complete, provide the pad pattern and the pin assignment you are using so the numbering can be verified before winding begins.

Regarding compliance: the supplier declares RoHS compliance, UL94V-0 flame-retardant bobbin, and 100% high-voltage and insulation testing (3.75 kV AC). No certificate numbers, standard references, or test reports appear in the material, so these are reported as statements rather than certified facts. If your equipment must meet a specific standard, request the certificate and test report for that standard before finalizing the device design.

Brand/Manufacturer: ZXY, Shenzhen Zhi Xiang Yuan Electronics Co., Ltd. http://www.zxycoil.com