PCM5121: PCM5121 spec and application questions

Hi John,

1. The PCM5121 cannot be used to drive headphones directly.  It is only line out capable (2.1VRMS output).

The minimum output impedance it can handle is 1kΩ.

2. These criteria are really for an audio amplifier.  I will re-direct this question to the amplifier team to see if they can recommend a device.

Thanks,
Paul

Hi John,

If you want to drive headphones directly from I2S source, here are some options you can take a look:

• TLV320DAC3120: Mono DAC, mono HP and mono Class-D
• TLV320DAC3100: Stereo DAC, stereo HP and mono Class-D
• TLV320DAC3101: Stereo DAC, stereo HP and stereo Class-D
• TLV320DAC3203: Stereo DAC, stereo HP (optional mono differential)
• TAS2505: Stereo DAC, mono HP and mono Class-D

Regarding output power to 100-ohms I'll need to double check. All our devices are rated for 16-ohm and 32-ohm.

We can also give some headphone amplifier options with analog inputs, you could use these next to a line driver DAC like PCM5121.

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators

Hi Ivan,

Thanks for your reply.

Customer prefer to use the PCM5121, and could you please help check the spec requirement list above to give recommendation of headphone amplifiers?

1, Design of any embedded audio jacks shall support headphones with impedance levels ranging from 32 ohms to 300 ohms

2, The SVDU(Smart Video Display Unit) shall be capable of providing up to 50 mW into the headset load of 100ohm on a seat audio output.

3, The SVDU shall provide volume control for the analog audio output to the headset.

4, When connected to 100 Ω load, the SVDU shall provide the following performance on analog audio outputs: 

 An audio frequency response within ±3.0dB from 50Hz to 12.5KHz on all audio outputs
 A total harmonic distortion (THD) of less than 1% from 30Hz to 12.5KHz
 A stereo audio separation greater than 20dB
 A signal noise ratio greater than 55dB for Digital audio sources 
    A cross talk between channel lower than -55dB (at maximum volume)

5, The SVDU audio outputs shall be free of artifacts such as buzz, whine, hum, ticks, cracking, or popping in the following conditions: When changing audio volume, during the power on phase, changing audio or video sources and if a reset occurs in the LRU.

6, The SVDU shall allow independent volume control with the following characteristics: Output power range from +2dBm to -55dBm, step level changes lower or equal to 2dB, at least 20 steps. Note : Once installed on the system, the default audio levels should be adjusted to be no more than 50mW in a 100 ohm headset. Adjusting the default audio level to get 50mW into 300Ω headset may lead to inappropriately high audio levels if a 100 Ω or 32 Ω headset was to be used.

7,All SVDUs audio outputs shall be protected against any permanent short circuit, and shall recover when the short circuit is removed

8, In all use cases, a short circuit on one SVDU audio output shall not affect other functions of that the SVDU, or the audio output performance of the other SVDU audio output

Thanks.

Hi Ivan,

Could you please help check if TPA6138A2 or TPA6130A2 can meet the requirement customer listed?

Thanks.