EI14 600 Ohm : 600 Ohm Audio Isolation Transformer - 1:1 Vertical PCB Through-Hole Hard Pin | 300 mH Inductance | 1000 VAC Hi-Pot | Voice Band 300 Hz - 3.5 kHz

1. Product Name

EI14 Vertical Audio Isolation Transformer, 600 Ω : 600 Ω. Reference part number ZXY-B2127-2 (EI14 series, hard-pin version).

The transformer is a compact, PCB-mountable low-frequency part that provides galvanic isolation and clean signal transfer between two audio circuits of equal impedance. It is built on a cold-rolled silicon steel core with a V-0 flame-retardant bobbin and is supplied in a vertical through-hole format with rigid pins for stable, assembly-friendly board mounting.

2. Feature

600 Ω : 600 Ω impedance matching — 1:1 turn ratio (1-3 : 4-6) within ±2%, so two identical 600 Ω lines are isolated without any impedance conversion.

Parallel inductance 300 mH — measured at 1 kHz / 0.25 V, 1-3 = 4-6 = 300 mH within ±25%.

Low DC resistance — 82 Ω ±15% on the primary (1-3) and 102 Ω ±15% on the secondary (4-6).

Low insertion loss — ≤2 dB max at 1 kHz keeps the signal level intact through the isolation barrier.

Voice-band frequency response — 300 Hz - 3.5 kHz within ±2 dB.

Withstand voltage 1000 VAC — primary-to-secondary isolation at 1 mA for 2 s.

Cold-rolled silicon steel core — high permeability with ultra-low magnetic loss, efficiency ≥90%.

V-0 flame-retardant bobbin — high dielectric strength and thermal stability; 130 °C / 155 °C dual-insulation wire.

Vertical hard-pin package — through-hole pins give a small PCB footprint and a mechanically secure, automation-friendly mount.

3. Advantage

Drop-in for existing layouts — the vertical hard-pin format and 1:1 ratio let the part replace an existing 600 Ω isolation transformer without redesigning the board or the network.

Signal integrity kept — low insertion loss and a ±2 dB window across 300 Hz - 3.5 kHz preserve voice-band quality.

Efficient magnetic path — the high-permeability silicon steel core runs at ≥90% efficiency with very low magnetic loss.

Stable over temperature — dual-insulation high-temperature wire holds electrical performance across the -40 °C to +85 °C operating range.

Breaks ground loops — galvanic isolation separates the two circuits and protects sensitive downstream circuitry.

Small, secure footprint — vertical pin layout keeps board area low while giving a mechanically secure through-hole joint.

Configurable family — 210 mH and 420 mH 600 Ω : 600 Ω versions and 1:10, 1:13 and 1:16 step-up versions are available on request.

4. Application

The EI14 is intended for voice-band signal isolation and for 600 Ω interface duty in equipment where a ground loop would otherwise carry hum:

Audio communication and intercom systems — voice signal isolation between line and handset or door station.

Wired landline telephones and intercom doorbells — 600 Ω line interface isolation on a compact board.

Voice signal isolation, clean audio transmission — removes the ground loop and the hum it carries.

Instrumentation signal isolation — separates a measurement front end from the equipment it feeds.

Low-voltage detection circuits — isolated sensing of a low-level line.

Industrial and portable control modules — 600 Ω interface circuits that need galvanic isolation in a small footprint.

5. Application Specifications

5.1 Environmental conditions

5.2 Electrical specification at 25 °C

5.3 Materials and construction

5.4 Outline dimensions, unit inch, as printed on the data sheet

Alternative EI14 configurations are available on request: 600 Ω : 600 Ω versions with 210 mH and 420 mH parallel inductance, and 1 : 10, 1 : 13 and 1 : 16 step-up versions.

6. Quality & Testing Assurance

Every unit is 100% inspected before shipment. Dielectric strength is verified at 1000 VAC for 2 s between primary and secondary; insulation resistance is confirmed to be at least 100 MΩ with 500 V DC applied; and temperature rise is checked to remain within 42 °C under full load. DC resistance, inductance, turn ratio, insertion loss and frequency response are measured at 1 kHz against the limits in section 5.2.

The transformer is RoHS compliant and is manufactured under an ISO 9001:2015 certified quality management system, with CCC, CE, RoHS and UL compliance.