Use TCXO successfully !

Wireless Connectivity Ultra-Wideband
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1

Hi all,

I have successfully run the DWM1000 module with a TCXO.
I have to put a LDO to supply 3V to TCXO AND VDDbatt pin.

My question is : Why do we need to supply this pin VDDbatt and the TCXO with 3V ?

I’ve tried to supply it with 3.3 V but without success.

Thanks :smiley: !

Erwan

2

Hi Erwan

What is problem when 3.3V supply is used?
Do you use an LDO as recommended in APH001 (chapter 6.5, TCXO Guidelines)
APH001 is available from: https://www.decawave.com/support#term5

/Leo

3

Hi Leo,

When we use the 3.3V power supply we are able to initialize the module but it is not possible to send or receive a message.
BUT I don’t use a 3.3V LDO to supply VDDbat and the TCXO (I didn’t check the APH0001 document). I just use the datasheet v2.13.

I 'll try it.

Thanks,

Erwan

4

Hello,

I have the same problem using a VCTCXO. My solution was to convert the 38.4 Mhz sine clipped signal that the oscillator outputs with less than 1Vpp to a square signal with +3V3 levels.

Regards,

Alex

5

Hello,

does anyone have [color=#333333][size=small]APH001 downloaded? I can only [/size][/color][color=#333333][size=small]download [/size][/color][color=#333333][size=small]product brief and datasheets from Decawave webpage.[/size][/color]

[color=#333333][size=small]Peter[/size][/color]

6

Try this?

7

Thank you.

8

Hello,

what did you used for converting VCTCXO output to +3V3 square signal?

Thanks,

Peter

9

Hi there,

I was wondering if anyone got the bottom of this issue? Is it that the VBatt pin or the TXCO pin is more sensitive to the voltage than the data sheet suggests?

Both cases here seem to suggest that that it may be the peak voltage from the oscillator that matters i.e. reducing the sine wave peak or dropping the 3V3 to 3V (which may also reduce the sine wave peak).

We are about to do this ourselves and so quite interested in the problem.

Many Thanks,

Dirk Vermaak.

10

I think my question has also something to do with this one:
https://www.decawave.com/decaforum/showthread.php?tid=117
I don’t remember the TCXO, but I think it was some Epson, min 0.8Vpp, clipped sine.
And a new board with TCXO only clocking the DW1000, the situation got worse, as if the processor was actually helping the TCXO to start.

11

If you’re that way inclined, this seems like an interesting problem. I have noticed that on the DW1000 datasheet (ver 2.12 page 35) the LDO for the TCXO and VBAT is shown as 3V, derived from 3V3, although the electrical data says 3V3 is OK.

Decawave, is there an omission in the datasheet or an errata? Is there some connection between a TCXO and the VBAT voltage that is not mentioned?

Cheers,
Dirk

12

Hello,

I’ve use this chip: IDT 830S21AMILF

https://www.google.es/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwjt1sDQnZPYAhXEwBQKHaNZDtsQFggoMAA&url=https%3A%2F%2Fwww.idt.com%2Fdocument%2Fdst%2F830s21i-final-data-sheet&usg=AOvVaw2PLA4aJou25lU8-u0NL89A

It’s a diferential to LVCMOS converter.

Regards.

13

Hello,

What did you use in R1 and R2 resistors in the bias to nClock at 830S21AMILF?

What is your VCTCXO?

Thanks,
Zimmer

14

Hi,

I’m trying to improve ranging accuracy by using a TCXO. I assume that a better timebase will produce more accurate ranges.

What (if any) improvements on range accuracy have you noticed when using a TCXO over the standard XTAL used in DWM1001 modules?

Cheers.