CC1190 at 434MHz ... ?

The minimum frequency for CC1190 is 470 MHz (see http://www.ti.com/lit/pdf/swra412). For 434 MHz you have to use a Skyworks or RFMD part.

470MHz is far away from the original specified 868MHz - if this works what's against to use it just a few MHz below at e.g. 434MHz?
Are there any internal limitations on the CC1190 or is it just not tested?

In AN119 maximum output is at ~21dB - is that because the CC1100 can't drive more and using CC1120 ~27dB could be expected?

I don't know about Skyworks/RFMD, pls. give me hint where to look

The CC1190 contain a highpass filter at the input and if you look at the app note I linked to you see that the output power start to fall from 510 to 470 MHz and even at 510 the output power is a few dB lower than the maximum at 868 MHz. Or in other  words, the chip is designed for 850 MHz to 950 MHz and has physical limitations making is not possible to use at low frequencies. 

We don't have a reference design around 433 MHz with a FEM but we have reference designs on other frequencies with FEMs bots from RFMD and Skyworks, see under the ref design section of http://www.ti.com/product/cc1120

got it, too bad that 1190 can't handle 434MHz.

I looked at SKY and found a 400-500 MHz FEM (65366), but this part is quite complicated with 28 (mysterious) pins, different supply voltages and no reference design using a single antenna.

RFMD has nothing below 868MHz.

Any more ideas?

thx.

Hi,

This can always be done with a discrete PA design.

Recommend the following part: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=2&cad=rja&ved=0CDEQFjAB&url=http%3A%2F%2Fwww.cel.com%2Fpdf%2Fdatasheets%2Fcs-ne5550234-ev04-a.pdf&ei=f6PTUqbUO6iS7QahloCgDw&usg=AFQjCNHnlEW7USCJmekFLH8rkp3Af0C53Q&bvm=bv.59026428,d.ZGU

Regards,

   Richard.

Richard,
many thanks for that hint.

Unfortunately, looking at the part I do have new concerns:
a. it needs two differnt supply voltages (Vg + Vd), one with 7.5V which is veryunusual in digital designs.
b. the both TL TL1/TL2 are synonym for layout stripes, but not practical in small board layouts. The notes refer to it, but without firm recommendations how to replace the TL with components.
c. Using a tranceiver I can't see how to use one antenna without an antenna switch. Do I miss something or would this be another design add-on?

Best regards

Hi,

a. This will work fine for one supply at 3.3 V.

b. Ignore the TL since the discrete components can compensate for these.

c. Yes, you will need one SPDT switch in addition to the discrete PA block.

Have used this type of design at 490 MHz, 3.3V and the performance was good. If you are working at 434 MHz, then the input matching of this transistor can be reduced since the matching in the app note is quite wideband.

Regards,

   Richard.

last one: can you recommend an according SPDT and design recommendation (never used these parts before)?

Hi,

Recommend SKYWORKS (SKY13323-378 or AS179-92LF) for a SPDT.

Regards, Richard.

thought I could avoid to dig deeper, but I have to...
I don't want to bother with Semtech & Co., so taking your suggestion with external PA, how do I integrate this in a CC112x design (tranceiver mode) in reality:
a. do I need to disconnect discrete PA input AND output via 2 x SPDT plus shutdown power for that PA whenever I want to RX with 112x?
Means putting this whole block out whenever it's not needed...
Example block:

Renesas recommends NE85630 NPN as LNA, but does not give any example integration; could I just skip it and connect in RX direct both SPDT?

b. Maybe easy for you to provide some more detail about your comment "then the input matching of this transistor can be reduced since the matching in the app note is quite wideband"

c. Did you measure what spurious/harmonics this design create?

Thanks again

Hi,

Only one SPDT is required, connect a PA and LNA in the following manner with CC112x:

The matching of the discrete PA is designed for a wideband and since you will be operating a one frequency this can be replaced with a single LC element instead of two stages of LCs.

We passed all ETSI requirements with the discrete PA design.

Regards,

    Richard.

The SKY65366-11 part is a nice part which I can recommend especially if you are interested in all the blocks such as PA, LNA & switch.

Contact Stefan (Stefan.Fulga@skyworksinc.com) to connect this to the radio. The SKY65366-11 is very similar to the chips we have used from Skyworks at 169 MHz.

Regards,   Richard.