ZXY EI19 Permalloy Audio Isolation Transformer - Permalloy Core 1:1 / 1:4 | 50 Hz - 20 kHz | 1250 V Isolation | DIP 3+3 Pins | 600:600, 600:10K, 10K:10K

1. Product Name

ZXY EI19 Permalloy audio isolation transformer. Uses a standard EI19 laminated Permalloy (nickel-iron) core, DIP 3+3 pin through-hole package, dimensions 19.5 x 17.5 x 17.0 mm, pin spacing 12.0 mm, and offers three standard impedance configurations: 600:600 (1:1), 600:10K (1:4), and 10K:10K (1:1).

This transformer couples voice and data signals between circuits where electrical isolation must be maintained. The magnetic path transfers the signal while the electrical path between primary and secondary remains open, breaking ground loops, rejecting common-mode noise, and passing audio content without loss. The multi-layer copper windings are wound on a precision bobbin and closed by a high-permeability Permalloy core, providing high inductance and low core loss across the audio band.

This product is offered in a single mechanical configuration: identical 19.5 x 17.5 x 17.0 mm footprint, identical 12.0 mm 3+3 pin spacing, and identical -40 °C to +125 °C temperature rating. The three models differ in winding, and with it the turns ratio, DC resistance, and the level the core can handle at 20 Hz. Therefore, the same PCB layout can carry a 600:600 line isolator, a 600:10K step-up stage, or a 10K:10K bridging stage without redesign.

2. Product Features

Electrical Isolation — Complete isolation between primary and secondary, preventing damage or burnout of the previous stage output from DC or ground potential differences.

Voice and Data Coupling — A single compact magnetic component carries both voice and data signals, suitable for audio, telecom, and modem circuits where a common reference ground is not allowed.

Wide Audio Band — 50 Hz to 20 kHz, with 20 Hz - 20 kHz response held within ±0.1 dB on the 600:10K and 10K:10K models and ±0.12 dB on the 600:600 model.

Eliminates AC Hum from Ground Loops — Cuts the ground path that couples mains hum into the signal.

Reduces External Interference — Suitable for balanced and unbalanced transmission.

High Common-Mode Rejection — Combined with ultra-low phase distortion, keeps the signal path transparent and lossless.

Dielectric Strength 1250 V — Verified by Hi-Pot test, 1 mA leakage current for 60 s.

Wide Operating Temperature Range — Stable operation from -40 °C to +125 °C.

3. Product Advantages

DIP Through-Hole Package — Mounts directly on standard 3+3 pin PCB layout, no special fixtures or tooling required.

High-Permeability Permalloy Core — High permeability with low core loss provides stable low-frequency performance.

Multi-Layer Copper Windings — High conductivity and low internal resistance, reflected in the DC resistance limits in the electrical specification table.

Precision Bobbin Insulation — Flame-retardant material with high dielectric strength and temperature rating of -40 °C to +125 °C.

Durable Tin-Plated Pins — Easy to solder and reliable circuit connection.

Customized Design — Turns ratio, impedance, pin assignment, lead length, and case style can be customized to application needs.

Factory Direct Supply — In stock for immediate shipment, reducing reorder lead time.

4. Application Areas

The EI19 Permalloy transformer is suitable for any application requiring signal isolation or conversion between balanced and unbalanced lines without introducing noise:

Communication Equipment and High-Speed Modems — Isolation between line interface and modem front end.

Telephone Coupling and Analog Modems — 600 Ω line coupling with isolation on both sides.

Mixer Signal Isolation Output — Balanced, isolated mixer output.

Multi-Channel Isolated Signal Output — Distributing a single signal to multiple isolated outputs.

Audio Equipment, Electronic Circuits, and Control Systems — Circuit isolation where ground noise must be suppressed.

Balanced-to-Unbalanced and Unbalanced-to-Balanced Conversion — Line interface without active stages.

In practice, the transformer sits between an unbalanced or noisy signal source and a sensitive receiving stage. It breaks the ground connection between them, prevents noise interference from traveling along the signal path, and outputs a clean isolated signal with full-bandwidth fidelity. The component is suitable for both new designs and retrofits of existing boards, and can be used in single-channel or multi-channel isolated output configurations.

5. Application Specifications

The table below lists the guaranteed electrical characteristics for the three standard impedance types, together with common mechanical and environmental specifications for the EI19 Permalloy series. All electrical parameters are specified at 25 °C. When selecting among the three types, compare the turns ratio, DC resistance, maximum 20 Hz input level, frequency response, and dielectric strength with the circuit's interface requirements.

5.1 Electrical Specifications (25 °C)

Values are taken from the product datasheet. DC resistance tolerance: M = maximum. All three models meet the same 1250 V dielectric strength requirement.

5.2 General Specifications

5.3 Specification Notes

6. Quality and Test Assurance

Production units are electrically tested at 25°C according to the electrical parameter table. The series withstands 1250V dielectric strength (Hi-Pot) test for 60 seconds with leakage current not exceeding 1mA. Turns ratio is held within ±2% tolerance, DC resistance (DCR) is verified against maximum limits for both windings of each type, and frequency response is checked over 20Hz to 20kHz with reference to +4dB.

Production takes place in an ISO 9001 certified factory, and the series complies with CE and RoHS standards for export markets. Tin-plated pins ensure consistent solderability and reliable board connection, the flame-retardant bobbin provides a dielectric barrier, and the Permalloy core maintains stable performance over the entire -40°C to +125°C operating temperature range. Samples and custom designs are available on request.