TLV320AIC1110: Output tone distortion

Vlad Nikiforov

Part Number: TLV320AIC1110
Other Parts Discussed in Thread: AIC111, TLV320AIC3254, TLV320AIC3262

Hi all,

I want use this chip for voice application, so I need digitize and play frequencies300..3400 Hz. The datasheet says chip is suitable for receiving and transmitting that frequencies.

So I wanted test how it works: ADC(mic in) and DAC(ear out).

Simply way do 2nd test(DAC) is put to PCM interface the DATA (one digital tone from 300 to 3400Hz) and watch the output.

See schemathic.

For example, I generated simple data (digital sine signal 3000Hz) on PCM_IN (PCM_CLK 2048000Hz, PCM_SYN 8000Hz) and seen signal output on TLV pins EAR2O and EAR1OP/N.

There are not ideal sine, as you seen.

There are STEPS of exponential function or charge/dischage capacity on the EAR_OUTPUTS

As you seen there are distortions on high voice freqs.

Registers are:

[0]9B [1]0B [2]40 [3]A0 [4]00 [5]00 [6]00 (MIC1 select, EAR1 select, Linear mode, filters - off)

or Reg [00]=0x99 for EAR2_OUT select.

What is that?

Is it normally?

Previous codec what we used is TP3070 produced in the last century, there is no distortions of signals.

over 7 years ago

0 Vlad Nikiforov over 7 years ago

Prodigy 140 points

another scale of DAC "STEPS"

0 Steve-Wilson over 7 years ago in reply to Vlad Nikiforov

TI__Mastermind 30220 points

Vlad,

you mentioned that you tested this Codec 2 ways, 1: mic IN to DAC out ( I assume this is PCM loopback?) and 2. data to PCMIN -> DAC.

Is this problem happening in both instances?

best regards,
-Steve Wilson

0 Vlad Nikiforov over 7 years ago in reply to Steve-Wilson

Prodigy 140 points

Hi Steve,

no, 1st test is passed ok.

In two words:

[sine signal about 10-20mV] -> [ MIC1 (or MIC2 choosed in registers) ] -> [Digital Data PCM_OUT ]

At this point I tested 2 ways:

1. Setted LOOPBACK bit in the register, so on the outputs EAR2O I seen distorted sine signal as in the above photos.

2. [PCM_OUT] -=TDM bus= -> [old codec TP3070] -> So I seen good sine signal on its outputs.

0 Vlad Nikiforov over 7 years ago in reply to Vlad Nikiforov

Prodigy 140 points

Timesize of steps is about 25us, so F=~ 40kHz.
In the PDF-Document "TI, SLAA_193 Feb2004" this frequency is sample rate (40kHz). But this doc is for chip AIC111, not for TLV320aic1110.
And in this doc it is recommended place analog output LP-filter(3rd order LC+RC) .
Why in the datasheet on TLV320aic1110 no words about that 40kHz?

This steps looks as low-quality(low freq) interpolation filter on outputs.

Why no one has yet noticed or answered?

0 Steve-Wilson over 7 years ago in reply to Vlad Nikiforov

TI__Mastermind 30220 points

Vlad,

can you send me the test tone file you are using?

best regards,
-Steve wilson

0 Vlad Nikiforov over 7 years ago in reply to Steve-Wilson

Prodigy 140 points

You have this chip ? Connect sine generator (any value >2500Hz ) on input in the loopback mode and look the output. And post here the oscillogram picture.

0 Steve-Wilson over 7 years ago in reply to Vlad Nikiforov

TI__Mastermind 30220 points

Vlad,

I have the EVM on order, and I will test this when I receive it.

best regards,
-Steve wilson

0 Vlad Nikiforov over 7 years ago in reply to Steve-Wilson

Prodigy 140 points

ok, I'll wait. May be someone else will answer

0 Steve-Wilson over 6 years ago in reply to Vlad Nikiforov

TI__Mastermind 30220 points

Vlad,

yes. I can reproduce this on the EVM. I've asked our design team to comment on this, but I want to be clear that this device is very old, and the original design team is long gone. The files for this device are archived, and our ability to support this device is limited.

we do have newer devices, that are less costly and do not have this problem. can you let me know what your requirements are and perhaps I can simply suggest a better fit?

best regards,
-Steve Wilson

0 Vlad Nikiforov over 6 years ago in reply to Steve-Wilson

Prodigy 140 points

Hi Steve-Wilson, thx for fast response.

During choosing chips I looked at the status on the web-site : it is "Active" (but date of the datasheet is Dec.2001)

(It is not so old. As I mentioned, last chip tp3070 have date in datasheet 1994)

About requirements: I need CODEC with analogue input-output (from -17dBm to +5dBm), support Linear and g.711 data mode, configuration port is spi/i2c/uart, small qfp package.

0 Steve-Wilson over 6 years ago in reply to Vlad Nikiforov

TI__Mastermind 30220 points

Vlad,

Well, the LM49352 would be perfect except it is only available in BGA package.

The TLV320AIC3254 or TLV320AIC3262 would work. the Mini DSP has ulaw/Alaw encoder/decoder blocks. You could make a process flow that facilitated that function. Both of those devices are available in QFN package, were released post 2010, and we still have design/systems support.

best regards,
-Steve wilson

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TLV320AIC1110: Output tone distortion