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DRV135: driving a 300ohm load

ajayt
Genius 9555 points
Part Number: DRV135

Hi, The device is specified for driving a 600Ohm load, would you still get good quality audio ( do you have any data as well) driving a 300ohm load, there is some flexibility in the power supply chosen

  • 0
    Genius 3945 points

    What audio system presents a 300-ohm load? Modern audio systems are "bridging," which means that low-impedance drivers (DRV135 has 50-ohm buildout resistors inside) connect to a moderate input impedance (10k or 20k) load. This reduces loading effects (distortion, among others) as well as voltage-divider effects which reduce output swing.

    The 600-ohm spec is an vestige of ancient telecommunications standards where a telephone line had to drive miles over a matched-impedance line. Nobody drives 600 ohm loads any more.

    Remember that as load increases (load resistance goes down), the amplifier needs to source or sink more current to drive to the same output voltage.  Data sheet Figure 14 has a charge of output swing vs output current. As expected, the output swing decreases with increasing drive, which corresponds to decreased load resistance. So expect distortion to increase with increased output voltage.

  • 0 in reply to Andy Peters
    TI__Mastermind 48006 points

    Hi ,

    Thanks Andy for answering the questions. 

    I believed that the question has been replied by Thomas. It you have additional questions. please let us know. 

    Best,

    Raymond