Hammond 101D 300:600 Ohm Center-Tapped PCB Audio Transformer

The 101D is a miniature, pin-type audio transformer for P.C. board mounting, with a 300 ohm center-tapped primary and a 600 ohm center-tapped secondary. It suits audio and communications designers who need a small, fully sealed line-matching part for a 300 to 600 ohm interface on a circuit board.

Construction is rugged and potted, producing a completely sealed unit that withstands severe environmental conditions, at a net weight of only 0.1 oz. The windings are interchangeable: the secondary may be used as the primary and the primary as the secondary, which effectively makes the 101D a 600 to 300 ohm part as well.

Nominal DC resistance is 20.4 ohms on the primary and 54 ohms on the secondary. The useful impedance range runs from 150/300 to 600/1200 ohms (primary/secondary). The 101D drawing specifies DCR of 20.4 ohms +/-20% on pins 1-3 and 54.0 ohms +/-20% on pins 6-8, output power of 20 dBm (100 mW), dielectric strength of 100 V RMS and a 105 degree C temperature class. Primary inductance measured at 1 V, 1 kHz open circuit is 13.15 H (109K ohms) with the halves joined in parallel and 44.0 H (290K ohms) in series, with leakage inductances of 15.64 mH and 63.50 mH respectively.

Frequency response holds +/- 0.5 dB from 300 Hz to 100 kHz at 100 mW, 200 Hz to 100 kHz at +10 and +15 dBm, and 300 Hz to 100 kHz at +20 dBm, measured with no DC current saturation. This part is RoHS and REACH compliant.