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

1. Product Name

ZXY EI19-Permalloy Audio Isolation Transformer. Permalloy (nickel-iron) core in a standard EI19 lamination, DIP 3+3 pin through-hole package, 19.5 x 17.5 x 17.0 mm with a 12.0 mm pin row pitch, supplied in three standard impedance configurations: 600:600 (1:1), 600:10K (1:4) and 10K:10K (1:1).

The transformer couples voice and data signals between circuits that must stay electrically separated. The magnetic path transfers the signal while the galvanic path between primary and secondary remains open, so ground loops are interrupted, common-mode noise is rejected and the audio content itself passes through intact. The multi-layer copper winding is carried on a precision bobbin and closed by a high-permeability permalloy core, which gives high inductance and low core loss across the audio band.

The part is offered in a single mechanical build: the same 19.5 x 17.5 x 17.0 mm body, the same 3+3 pin row pitch of 12.0 mm and the same -40 °C to +125 °C rating. What changes between the three types is the winding, and with it the turns ratio, the DC resistance and the level the core can take at 20 Hz. That is why one board layout can carry a 600:600 line isolator, a 600:10K step-up stage or a 10K:10K bridging stage without redesign.

2. Feature

Galvanic isolation — primary and secondary are fully separated, so the output stage of preceding equipment is not damaged or burned out by DC or ground potential differences.

Voice and data coupling — one compact magnetic component carries both speech and data, for audio, telecom and modem circuits that must not share a reference.

Wide audio band — 50 Hz to 20 kHz, with the 20 Hz - 20 kHz response held within ±0.1 dB on the 600:10K and 10K:10K types and ±0.12 dB on the 600:600 type.

Solves AC hum from ground loops — breaks the ground path that couples mains hum into the signal.

Reduces external interference — works in balanced and unbalanced transmission alike.

High common-mode rejection — together with ultra-low phase distortion, it keeps the signal path transparent.

Dielectric strength 1250 V — verified by Hi-Pot at 1 mA for 60 s.

Wide temperature range — stable operation from -40 °C to +125 °C.

3. Advantage

DIP plug-in through-hole package — mounts directly on a standard 3+3 pin PCB layout with no special fixtures or tooling.

High-permeability permalloy core — high permeability with low core loss, giving stable low-frequency performance.

Multi-layer copper winding — high conductivity and low internal resistance, as reflected in the DCR limits of the electrical table.

Precision bobbin insulation — flame-retardant material with high dielectric strength and a -40 °C to +125 °C temperature rating.

Durable tinned pins — easy soldering and a reliable circuit connection.

Customized designs — turns ratio, impedance, pin assignment, lead length and case style can be tailored to the application.

Factory-direct supply — stock is held for immediate shipment, which keeps repeat orders short.

4. Application

The EI19-Permalloy is used wherever a signal has to be isolated, or converted between balanced and unbalanced lines, without adding noise:

Communication equipment and high-speed modems — isolation between the line interface and the modem front end.

Telephone coupling and analog modems — 600 Ω line coupling where the two sides must stay isolated.

Mixing console signal isolation output — balanced, isolated console output.

Multi-channel isolated signal output — one signal distributed to several isolated outputs.

Audio equipment, electronic circuits and control systems — isolation for circuits that must reject ground-borne noise.

Balanced-to-unbalanced and unbalanced-to-balanced conversion — line interfacing without an active stage.

In practice the transformer sits between an unbalanced or noisy source and a sensitive receiving stage. It breaks the ground connection between the two, stops noise interference from travelling along the signal path, and delivers a clean isolated output with full-bandwidth fidelity. The same part suits new designs and retrofit work on existing boards, and can be used singly or in multi-channel isolated output configurations.

5. Application Specifications

The tables below list the guaranteed electrical characteristics of the three standard impedance types and the general mechanical and environmental specification of the EI19-Permalloy series. All electrical parameters are specified at 25 °C. When choosing between the three types, compare the turns ratio, DC resistance, maximum 20 Hz input level, frequency response and dielectric strength against the interfacing requirement of the circuit.

5.1 Electrical specification (25 °C)

Values are reproduced from the product specification sheet. DCR tolerances: M = Max. All three types share the same 1250 V dielectric strength requirement.

5.2 General specification

5.3 Notes on the specification

6. Quality & Testing Assurance

Production units are electrically tested at 25 °C against the parameters of the electrical table, and the series carries a 1250 V dielectric strength (Hi-Pot) requirement at 1 mA for 60 seconds. Turns ratio is held to ±2 %, DC resistance is verified against the maximum limits of the two windings for each type, and the frequency response is checked from 20 Hz to 20 kHz against the +4 dB reference.

Manufacturing runs in an ISO 9001 certified factory and the series holds CE and RoHS compliance for export markets. Tinned pins ensure consistent solderability and a reliable board connection, the flame-retardant bobbin provides the dielectric barrier, and the permalloy core keeps performance stable across the full -40 °C to +125 °C operating range. Samples and customized designs are available on request.