Hi, we changed from regular crystal to TCXO after experiencing some issues with crystal frequency previously.
We are now using JT21G However, when we use the recommended capacitor value (2200pF) for TCXO from dw3000 datasheet, with 1.8V VDD_TCXO, we cannot get the 800mV amplitude required by dw3000.
We just want to know what’s the official recommended TCXO for dw3000 now and where we can buy it? The recommended ones on the datasheet are no longer available.
capacitor on TCXO to the gnd does not make sense…
Sorry, i do not have P/N of recommended TCXO, but are they not the same as in DW1000?
there are some changes in the datasheet and we would like to know something that has been definitely demonstrated to work with dw3000 and is still manufactuered
here is the schematic for the TCXO part in our design
you need 3000-3300 pF
Thanks for the reply. Is this value range based on previous experience with dw3000 tcxo?
It`s based on KCL/KVL
Think how 2200 pF value was obtained.
And JT21 is a bad choice. Vout=0.8V (min)
DW3000 need V=0.8V (pk-pk, min). There is no any margin.
And voltage at DW3000 will be always less then Vout, because C11 and R11||R10 form divider.
But you can not remove R10 and R11, because they provide DC bias for AC-coupled signal.
P.S.
You can try remove R10, R11 and replace C11 with resistor (0 to 10-33 Ohm).
No idea how long trace is… But this is fix for lab. usage, not good for production samples.
Thanks for the advice.
We notice that the two recommended TCXO’s in the DW300 datasheet are also both 0.8V min, see
These recommended parts are also both obsolete and there is no stock available.The JT21 was selected based on the properties of the datasheet-recommended TCXO.If the JT21 is a bad choice, then what is a good one?
