[SOLVED] How To Use The UDA1361 ADC?

Hi there,

I have a question about using the UDA1361 ADC in my project. I just soldered one up to a breakout board and have it wired into a circuit on my breadboard just like the ideal circuit description in the datasheet, minus the inductors. I have the following connections to the control pins:

Pin 7 (PWON): Voltage divider = 1.65V -> mode set to 0db gain.
Pin 8 (SFOR): 3.3V -> mode set to MSB justified output.
Pin 14 (MSSEL): 3.3V -> mode set to master mode.

The datasheet says:

The master mode drives pins WS (word select; 1fs) and BCK (bit clock; 64fs).

Click to expand...

Does this mean that the WS and BCK pins do not need to be controlled by a microcontroller signal? I have tried to test this by attaching my function generator to the SYSCLOCK input of the UDA1361, with a frequency of 2MHz. My BCK, WS and DATAO pins are holding at 0V.

Am I missing something from the datasheet? Here is the link:
https://pdf1.alldatasheet.com/datasheet-pdf/view/19863/PHILIPS/UDA1361.html

Any help would be much appreciated,

Thanks,

Judd

Sorry for the typo, meant to say pin 8.

Does the sample rate really need to be at an audio standard? (Probably sounds like a stupid question) My signal generator doesn't go above 3.3MHz, I will have to try building an oscillator or something.

Pin 1: 1.662VDC, no AC component
Pin 2: 1.656VDC, no AC component
Pin 3: 1.668VDC, no AC component
Pin 4: 0.000VDC, no AC component
Pin 5: 3.300VDC, no AC component
Pin 6: 3.300VDC, no AC component
Pin 7: 1.626VDC, small AC component leaking from pin 8: Vmin = ~1.42V, Vmax = ~1.89V, Vpp = ~400mV
Pin 8: Clock signal from generator, Vpp = 3.3V, 2MHz frequency
Pin 9: 3.300VDC, no AC component
Pin 10: 0.000VDC, no AC component
Pin 11: 0.857VDC, no AC component
Pin 12: 0.600VDC, no AC component
Pin 13: 0.278VDC, no AC component
Pin 14: 3.300VDC, no AC component
Pin 15: 0.000VDC, no AC component
Pin 16: 3.300VDC, no AC component

This application is not suited for a breadboard.

Click to expand...

Do you think it could still work though? I am trying to keep connections very short, good breadboard layout etc. so it shouldn't make too much difference? I have done experiments like this before with success.

Thanks,

Judd

HI,

SFOR = pin 6 (not pin 8)

Does this mean that the WS and BCK pins do not need to be controlled by a microcontroller signal?

Click to expand...

Exactely. They are outputs in master mode.

2MHz Sys_clock = 7812.5 Hz sample rate. = No audio standard. (But this is an audio ADC.)

--> measure all pin´s voltagesand tell us. Dc signals with a DVM. AC signals with a scope.

--> This application is not suited for a breadboard.

Klaus

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- - - Updated - - -


Hi,

Sorry for the typo, meant to say pin 8.

Click to expand...

..but it is pin 6!

****

Does the sample rate really need to be at an audio standard?

Click to expand...

If you want to use it for audio, then YES.

****
Voltages:
All - except your digital interface - seem to be correct.

I assume there is a bad connection in one of your breadboard-to-ADC connections.

Did you measure all voltages directely at the IC pin? (don´t measure on the breadbord, nor at the wires. ADC pin is the most reliable.)

AC at pin7 is a bit high...

***
Try to use 12.288MHz as sys clock input. This is the standard frequency for 48kHz audio sampling rate.

Klaus

I thought for sure I typed pin 6, although it was getting pretty late last night... Sorry!

I did measure from the ADC pin but I will try again from it and post results.

I will also try the 12.288MHz input signal but I have to build a circuit that will output that, so I will get back to you shortly on how that works out.

- - - Updated - - -

Solved the problem! It was due to a poor solder joint on Pin 9. My 2MHz input seems to work just fine which is a relief, now I will be able to drive this thing from a micro. Remeasuring from the actual pins and not the pads of the breakout board helped a lot.

Thanks for all your help,

Judd