Hello everyone!
I have to use Melexis TH72032 ASK Transmitter @ 868MHz and the datasheet says I need a crystal @ 27.134375MHz, but all the manufacturers I found are not producing it anymore, and the stock at mouser, farnell, digikey, arrow,... is 0. I've search for two days now and found nothing.
So I have two alternatives:
- Use another crystal at a close frequency (e.g. 27.12MHz), but I don't know how this will affect the output frequency. In theory, the output frequency is 32*fref according to the data sheet, so if I use 27.12 the output will be 867,84MHz, which is a difference of 0.46MHz. The question is: will I need to change the output matching filter, or with such a "little" difference won't be necessary?
- Generate somehow that frequency. I have no idea on how to do this (except by using an external signal generator, which is obviously out of the table).
It is my first pcb design and it's driving me crazy!! Any help would be really appreciated.
I'm following the test circuit given in the HT72032 datasheet (which you can find here: http://www.melexis.com/Asset/TH72032-DataSheet-DownloadLink-4807.aspx )
Thanks!
Carlos
I have to use Melexis TH72032 ASK Transmitter @ 868MHz and the datasheet says I need a crystal @ 27.134375MHz, but all the manufacturers I found are not producing it anymore, and the stock at mouser, farnell, digikey, arrow,... is 0. I've search for two days now and found nothing.
So I have two alternatives:
- Use another crystal at a close frequency (e.g. 27.12MHz), but I don't know how this will affect the output frequency. In theory, the output frequency is 32*fref according to the data sheet, so if I use 27.12 the output will be 867,84MHz, which is a difference of 0.46MHz. The question is: will I need to change the output matching filter, or with such a "little" difference won't be necessary?
- Generate somehow that frequency. I have no idea on how to do this (except by using an external signal generator, which is obviously out of the table).
It is my first pcb design and it's driving me crazy!! Any help would be really appreciated.
I'm following the test circuit given in the HT72032 datasheet (which you can find here: http://www.melexis.com/Asset/TH72032-DataSheet-DownloadLink-4807.aspx )
Thanks!
Carlos
Last edited: