INA1620: THD vs Vpp and Parallel'd chip option

Barry Klein

Part Number: INA1620
Other Parts Discussed in Thread: BUF634A,

I see on the datasheet page 9 that the performance of this chip really suffers if the output amplitude is over 1Vrms. To drive certain aviation headsets to necessary high output levels (they stick earplugs in their ears) I need much higher Vpp. What happens when two chips are paralleled like often suggested by audio enthusiasts? Does this allow higher Vpp at lower distortion or just higher current at lower Vpp? The BUF634A also shows this behavior, beyond 10Vpp.

over 2 years ago

0 Chris Featherstone over 2 years ago

TI__Mastermind 25160 points

Barry,

Configuring the parallel solution will only allow for more output current drive such that the device doesn't current limit early and create distortion early on. This allows a device such as the INA1620 drive very heavy loads. I have tested the below circuit with even 3 ohms of resistance. The voltage output swing will remain the same regardless of single versus parallel although you will be able to drive more power to the headphones with the parallel solution.

https://www.ti.com/lit/an/sboa352/sboa352.pdf?ts=1663951335026&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FINA1620

The THD+N is shown below with the single and the parallel configuration. You can get significantly more output power drive with the parallel solution while maintaining THD+N.

Best Regards,

Chris Featherstone

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INA1620: THD vs Vpp and Parallel'd chip option