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TLV320AIC3111: Decoupling capacitors required for the CODEC lines

Part Number: TLV320AIC3111
Other Parts Discussed in Thread: TLV320AIC3120

Hello,

We are in the process of developing our project and we are referring to the TLV320AIC3111 EVM schematic for the same. On that, we can see 4 capacitors on the SPL and SPR lines which probably act as decoupling capacitors for the power supply.

However, when we referred to the TLV320AIC3120 EVM schematic, there are only 2 capacitors on the SPL and SPR line. 

We have a serious space issue on our PCB and we need to optimize space by reducing size and number of capacitors. Would it serve our purpose by using only 2 capacitors as in the 3120 schematic? What is the minimum size and number requirement for the 3111 CODEC?

  • Hello,

    The AIC3120EVM is a little deceptive because there is an additional 100uF of capacitance sitting on the other side of the current loop monitor. We recommend using at least the values recommended in the Figure 5.1 which show a total of roughly 47uF of capacitance on these lines (22uF each).  You can use less capacitance but the performance results may vary slightly from the datasheet performance.

  • Souvik, 

    On the AIC3120 there is only 1 Class D amplifier.  The TLV320AIC3111 has 2,  thus twice as many decoupling capacitors. 

    I do not recommend removing them,  You can take a look at the TLV320AIC3110EVM-U which uses 3 caps, 1x100uF and 2 x 0.1uF  You should be able to reduce the 100uf cap to 47uf without any issues. 

    best regards

    -STeve Wilson

  • Thank you Steve and Collin,

    We shall be referring to fig 5.1 as mentioned above for our design.

    We are trying to reduce the size of the capacitors as well. The capacitors like the 47uF across HPLOUT AND HPROUT are 1210 sized on the EVM. Can we use 1206 or lower for them? Will tantalum caps be a better choice considering lower DC bias variation?

    What sizing do we need to use for caps across SPVDD, HPVDD, and MIC1LP?

    On the EVM we have a 0.47uF cap on MIC1LP but in fig 5.1, it is a 1uF cap. What effect will that have on the audio?

    Also, we were concerned with the issue of microphonics on the MIC1LP capacitor. Will it suffice if we use C0G capacitors on these lines?

  • As long as you meet the voltage rating with the smaller package capacitors then reducing their physical size should not cause issues.

    The capacitors on the input pins (MIC1LP) will set the high-pass filter cutoff frequency for the inputs.  Making them smaller will increase the frequency of the high-pass cutoff and you may start missing some lower-frequency audio signal information.

  • If we don't need the right channel speaker, can we remove the supply to SPRVDD AND SPRVSS and use just SPLVDD AND SPLVSS?

  • This is not advised as it may negatively interfere with other internal operations.

    Is there a reason that you wouldn't use the AIC3120 at that point which only has one class-D amplifier?