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16 Top Kickass 16 bit ADConverter

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Top Kick Ass ADConverters

16 Top kickass 16 bit ADConverter

The A/D converters are complex and sophisticated systems: there are many A/D types and every type can have several configurations. So the ADC are used to transform analog information, such as audio signals or measurements of physical variables (e.g. force or shaft rotation) into a form suitable for digital handling.
Lately I have an idea that is whirling through my head. I would like to realize a project using a micro-controller that can reproduce audio files. A waveform audio file, or simply .wav after its extension, is a common type of sound file. The wav file has two qualities and one drawback: it is a lossless format, that is the wav file format does not compromise the audio quality, moreover it is very easy to edit and manipulate with software. The drawback is that its extension is very large: a four-minute song can occupy over 40 memory megabytes! (2*44000*2*4*60=42240000/1024=41250MB). The A/D for audio applications convert the analogical audio in digital audio, this conversion must take account of:

Sampling frequency
The sample frequency shows the samples number per second that are digitally recorded, fractioning the sound wave in many small pieces, called samples, and giving them a value. The sampling frequency is measured in Hertz (Hz).
A 11 KHz frequency is suitable for the human voice recording.
A 22 KHz frequency is suitable for a tape recording.
A 44 KHz frequency is suitable for a cd recording.
Reducing the sampling frequency has a quality loss as consequence.

Bit number
The bit number represents an audio wave dimensions and it can be 8 or 16 bits. Of course an 8 bit resolution has a lower audio quality compared to a 16 bit resolution.

Channel type
3 methods exist to mix the audio channels during the compression : mono, stereo, joint stereo.

Conversion type
- Flash, it is really fast, limited resolution (12 bit max), used for video, test instruments, telecommunication applications.
- SAR, successive approximation register perhaps the most diffused, mostly found as micro-controllers peripheral.
- Sigma Delta, recently introduced, it is widely spread in consumer audio devices.
- Dual slope, low speed, old fashioned, good for low level signals.

Before talking about the audio A/D suitable for my project I want to remember the main A/D parameters.

SPS: conversion speed, it is expressed in sampling per second.
Resolution: generally it is expressed in Bit (8, 10, 12 etc.) and it is the division grade of an analogue input. Let's make an example: an 8 bit A/D can divide an analogue input in 256 steps (28 = 256), so if the input voltage changes from 0 to 5V we will have that 5/256 (19,5 mV) is the minimum conversion step.
DNL/INL: differential non linearity/integral non linearity.
When a DC is applied to an A/D, it should be converted according this formula: Vfs / 2 exp. (n). Vfs is the maximum input voltage and n is the A/D bit number. In reality the conversion has always an error, called DNL. Moreover the integral non linearity(INL) must be added to this error. INL is the sum of the all DNL errors in the transfer function of the A/D converter.
SNR: signal to noise ratio.
When a sinusoidal wave is applied to an A/D, step values as output are obtained (due to the resolution). The conversion errors show under the noise form.
THD: total harmonic distortion.
SINAD: signal to noise and distortion (ratio between SN and THD).
ENOB: effective number of bit.

So for my project I'm looking for A/D converter:
- SPS at least 44 KHz (or more for better performances).
- Resolution 16 to 24 bits
- Number of channels at least two (stereo or more).

Many manufactures produce the A/D converters, but only some of them produce the ones I am looking for. Here following I will give an A/D list with a short description of their features. Of course clicking on the manufacturer web you can find the data sheets and other pieces of information.

1.PCM1801 (Texas In.) is a low cost A/D. It has an anti-aliasing filter included, a single ended analog voltage input, a serial interface that supports slave mode operation and two data formats. (Data sheets and application notes available @: http://focus.ti.com/docs/prod/folders/print/pcm1801.html)

PCM1801

2.PCM1870 (Texas In.) is a low power A/D. It has sound effects, auto level control (ALC), control I/F SPI-I²C, high pass filter and two stage notch filter. (Data sheets and application notes available @: http://focus.ti.com/docs/prod/folders/print/pcm1870.html)

3.PCM1870A (Texas In.) is very similar to PCM1870. It has some programmable functions by register control in addition and the 24 DSBGA package only. (Data sheets and application notes available @:
http://focus.ti.com/docs/prod/folders/print/pcm1870a.html )

4.PCM1803 (Texas In.) is a high performance, low cost A/D. It includes a digital decimation filter and an high pass filter which removes the DC component of the input signal. (Data sheets and application notes available @:
http://focus.ti.com/docs/prod/folders/print/pcm1803.html)

5.AK5355 (AKM) is a low voltage ADC. The analog signal input is single-ended, eliminating the need for external filters. (Data sheets and evaluation board manual available @: http://www.akm.com/prodfolder-adc.asp?p=AK5355)

6.AK5701 (AKM) has an ALC (Auto Level Control) circuit that is suitable for portable application with recording function. (Data sheets and evaluation board manual available @: http://www.akm.com/prodfolder-adc.asp?p=AK5701)

AK5701

7.AK5702 (AKM) is a 4-channel ADC. Its software is compatible with the AK5701 stereo version. (Data sheets and evaluation board manual available @:
http://www.akm.com/prodfolder-adc.asp?p=AK5702)

8.AD1870 (Analog Devices) is an ADC based on sigma-delta technology intended primarily for digital audio bandwidth applications. (Data sheets and application notes available @: http://www.analog.com/en/analog-to-digital-converters/audio-ad-converter...)

9. AD1877 (Analog Devices) is very similar to AD1870. Every single-ended channel consists of a fourth-order one-bit noise shaping modulator and a digital decimation filter.(Data sheets and application notes available @:
http://www.analog.com/en/analog-to-digital-converters/audio-ad-converter...)

10. MAX1167 (Maxim) is a low power 4-channel A/D. It has a high speed SPI/QSPI/MICROWIRE compatible I/F.
(Data sheets and application notes available @: http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3997/t/qv#Applications%2FUses)

11. MAX1168 (Maxim) is similar to MAX1167, but it has 8 channels. It includes a data bit transfer input to select between 8 bit wide or 16 bit wide data transfer modes. (Data sheets and application notes available @:
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3997/t/qv#Applications%2FUses)

12. MAX1300 (Maxim) is a low power, successive approximation A/D. It provides 8 (single- ended) or 4 (true differential) analog input channels.
(Data sheets and application notes available @: http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4943)

MAX1300

13. CS5340 (Cirrus Logic) is a complete A/D for digital audio systems. It removes the need for an external anti-alias filter thanks to a 5th-order multi-bit delta-sigma modulator followed by digital filtering.
(Data sheets and evaluation board available @: http://www.cirrus.com/en/products/pro/detail/P1028.html)

CS5340

14. CS5341 (Cirrus Logic) is very similar to CS5340 A/D. It is ideal for audio systems requiring wide dynamic range, negligible distortion and low noise.
(Data sheets and evaluation board available @: http://www.cirrus.com/en/products/pro/detail/P1029.html)

15. CS5361 (Cirrus Logic) is an A/D that uses a differential architecture which provides excellent noise rejection. (Data sheets and evaluation board available @:
http://www.cirrus.com/en/products/pro/detail/P1001.html)

16. CS5381 (Cirrus Logic) is a specific audio A/D. It is pin compatible with CS5361, it has a differential analog architecture and a low latency digital filtering.(Data sheets and evaluation board available @: http://www.cirrus.com/en/products/pro/detail/P1024.html)

CS5381

Surely some of the above mentioned A/D are "wasted" for my project, in the meaning they have higher performances compared to my needs, but it does not matter because it is a recreation only. Just to have an idea about an A/D price I have given a look to the Farnell (www.farnell.com) catalogue and I have found, for example, that the AD1877 costs € 14,30.
To conclude this article let's summarize some of the main features of the above mentioned A/D.

Resolution
( Bit )

Sampl.
Rate

(kH-max)

Channels

SNR/DNR
(dB)

Price



Farnell Code

____________________________________________________________________

PCM1801

16

48

2

93/

$
3/100
units

PCM1870

16

50

2

90/

$
2.25/100
units

PCM1870A

16

50

2

90

$
1.80/100
units

PCM1803

24

96

2

103

$
1.55/100 units

AK5355

16

48

2

85/

//

AK5701

16

48

2

78/

//

AK5702

16

48

4

78/

//

AD1870

16

256
or 384 x fs

2

/92

$
7.59

AD1877

16

256
or 384 x fs

2

/94

14.30

1438337

MAX1167

16

200
(ksps )

4

86/

$11.04/1k

MAX1168

16

200
(ksps )

8

86/

$11.04/1k

MAX1300

16

130
(ksps )

8

86/

$31.95/1k

CS5340

24

192

2

/

//

1023404

CS5341

24

192

2

/

//

1023405

CS5361

24

192

2

/

//

1023411

CS5381

24

192

2

/

//

1023417

ADC Converter from Farnell

The format of the table sucks!

Can't somebody fix this table format? It is a pain in the neck to read it!

I'll speak with

I'll speak with theĀ Administator to change it Sealed!

Thank you forĀ the recommandation!

 

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