High Performance RF Modulators, PLL and VCO products

Forum Post: RE: Loop filter calulation tool W7 64bits

Hiroshi Kezuka — Sat, 08 Jun 2013 00:27:00 GMT

Hi Adam,

I confirmed this version is operate normaly on my Windows7 PC.
Thank you.

Regards,
Hiroshi Kezuka

Forum Post: RE: Conflicting result for LMX2581 software tools

Dean Banerjee — Tue, 04 Jun 2013 00:35:00 GMT

Frank,

No, you are not missing anything and you are correct to observe this.

The clock design tool blindly designs for the loop bandwidth for the optimal jitter, disregarding fractional spurs and disregarding the fact that the capacitors will be small. So I recommend NOT using the "Recommend Design and Calculate" and instead just specify your loop bandwidht and phase margin and just calculate with this. The loop bandwidth and phase margin you pick will probably be lower than what the tool designs.

The 3.3 nF rule for C3 is perhaps a little overconservative and perhaps you could go down to 1.8 nF, but this is to get the best possible VCO noise. But 3.3 pF is way too small. We are working on a new tool now, but until then, you can use the tool, but be cautions of this C3 value and don't design as wide loop bandwidths as it recommends. Also, try higher phase detector frequencies and higher charge pump currents to get the C3 value higher.

Regards,

Dean

Forum Post: RE: Software issue with the LMX2581 Codeloader program

Dean Banerjee — Tue, 04 Jun 2013 00:31:00 GMT

Frank,

This is just a GUI issue. To do it on codeloader, you ignore the divide and go to the Bits/Pins page. Then on the OUTA_MUX or OUTB_MUX, you select "Bypass"

Regards,

Dean

Forum Post: RE: TRF372017EVM

Adam Torma — Mon, 03 Jun 2013 16:01:00 GMT

Mingran,

Yes, you need to have a reference signal on the REFIN pin to provide the phase/frequency detector a reference signal to compare to the signal being feed back from the voltage controlled oscillator.

You can find the information on the reference signal parameters on page 5 of the data sheet under "Reference Oscillator Parameters."

Adam

Forum Post: RE: TRF3765: IBIS or SPICE or Touchstone model and skew time between LOs

Simona Mazzocchi — Wed, 29 May 2013 15:36:00 GMT

Hi Adam,

OK, thanks a lot for your answer.

Could you tell me if you can send me the Touchstone file for the TRF3765?

I look forward to hearing from you.

Best Regards,

Simona

Forum Post: RE: Fractional/Integer-N PLL Basics Technical Brief SWRA029

Michael Choi — Wed, 08 May 2013 09:41:00 GMT

Dear Mr. Torma;

I would like to thank you for your reply.

The purpose of my question was to determine the practical usefulness of the information I was reading in the app note.

Please take notice that there were two replies to your reply, not one. The reason why I had posed the question about whether a value was derived from experimental data was to determine the practical usefulness of the information I was reading.

I reference textbook analysis and app notes to verify the accuracy of the information I am reading. If a mathematical example is provided for the reader to get the "general idea" but cannot be practically applied then please assert in your reply that the example is not intended for practical application. I am going to assume by your answer, that this method cannot be practically applied. If this is correct, please state so - ambiguous replies are not helpful.

Page 16 of the app note defines He(s) = 1 - H1(s). H1(s) appears to be "closed loop transfer function" of the PLL. PLL textbooks have defined the "error function" differently than this equation. There may be a mistake with regard to referencing H1(s) in this equation as H1(s) is defined in this app note. I have checked the equation that explicitly sets forth He(s) in the form of a ratio/fraction and this definition is consistent with the equations that I have read in PLL textbooks.

With regard to the interpreted meaning of the number, 1, in the equation, 1-H1(s), can you please assert whether that one is defined as a numerical one (a number), or is that one intended to denote 1 angular unit (such as 1 radian) when this equation is utilized for practical application, or analysis. An explicit answer with regard to this question is sought, can you please comply with this request?

Forum Post: RE: LMX2485E boundary spurs

taylor Smith1 — Tue, 07 May 2013 04:20:00 GMT

Could this be related to your power supply or a digital load that is pulsing at 5KHz?

Forum Post: RE: LMX2485E Eval Board to CST Studio Suite

Daniel Pulito — Thu, 02 May 2013 13:23:00 GMT

I beleive Altium can export ODB++ files and CST can import them as well. Is ODB++ something we can try?

Thanks,

Dan

Forum Post: RE: TRF372017EVM - 2

Adam Torma — Thu, 25 Apr 2013 15:51:00 GMT

Mingran,

Decrease the input power level of the IQ signals going into the TRF3720. My results indicate -34dBc at the second harmonic you indicated, marker 1 on your screenshot.

Adam

Forum Post: RE: DC component at the output of TRF372017EVM

Adam Torma — Tue, 23 Apr 2013 03:13:00 GMT

Stefano,

The marker you placed on your screen shot near DC is part of the roll off from the DC signal internal to the instrument.

Adam

Forum Post: RE: TRF 1112/1212 and TRF 1222/1122 where i can buy these?

Giorgos Fovakis — Fri, 19 Apr 2013 19:39:00 GMT

Yes i saw this but you propose TRF2443EVM and i don't understand how to use it. Except the manual user guide is there any data with examples of 2443 to make it easier for some beginner like me ?

Thanks George

Forum Post: RE: TRF371125, what is minimum base-band output frequency?

RJ Hopper — Fri, 19 Apr 2013 19:28:00 GMT

Yes, this part is specifically designed for ZIF applications.

Forum Post: RE: TRF371135 query

RJ Hopper — Fri, 19 Apr 2013 19:23:00 GMT

(1) The typical values of IQ imbalance (phase and amplitude) of this chip over the entire frequency range.

A: The I/Q is not specifically measured. Image rejection is measured. Typical performance is 40 dBc regardless of RF frequency.

(2) The LPF is adjustable with values between 0 to 255. We need to know the LPF type (I guess it is analog. Is it chebyshev?). and the taps of the filter for the widest LPF (Cutoff approx 15MHz by setting a value of 0). We see that there is a peaking in the response and we need to equalize this, hence we need the impulse response of the filter.

A: The LPF is an active 8th order Butterworth type filter.

(3) The SPI is not very stable. Our Logic Analyser has dumped the three pins and it meets the timing diagram very accurately. Is there anything missing in the timing diagram? We get is to work 80% of the times, some times it will not configure. We have used the clock below 20MHz (tired at 5MHz and 10MHz).

A: I have not seen sensitivity to SPI stability previously. This could be a USB driver issue.

Forum Post: RE: NEED INFORMATION- TRF371109IRGZR

RJ Hopper — Fri, 19 Apr 2013 19:18:00 GMT

The TRF3711xx are utlilize similar die and package. Responses from earlier post are applicable for this part as well. --RJH

Forum Post: RE: NEED INFORMATION- TRF371109IRGZR

RJ Hopper — Fri, 19 Apr 2013 19:16:00 GMT

The temperature ratings and information that are available for the device are located in the datasheet. The typical power dissipation is in the datasheet. For other temperature ratings and/or max power dissipation ratings and weight information please contact your local sales representative and most of the information can likely be retrieved.

Forum Post: RE: GERBER files

RJ Hopper — Fri, 19 Apr 2013 19:08:00 GMT

Unforthunately, Gerber files are not avaialble for this product.

Forum Post: RE: TRF 3711X EVM not responding...

RJ Hopper — Fri, 19 Apr 2013 19:06:00 GMT

Check the jumper settings to make sure the supplies are in plance. Make sure the software GUI is communicating and that the none of the power down registers are engaged.

Forum Post: RE: TRF371109 BBoutn and BBoutp pins

RJ Hopper — Fri, 19 Apr 2013 18:58:00 GMT

The BBout pin-out on the TF3711-09 are technically labelled correctly. The pin-out on the -25 flavor and -35 have one set of p,n flip-flop to match up to the pin-out of most ADCs so that the lines do not cross. In any event, the swapping of p,n can easily be reversed digitally so the layout is typically routed most efficiently for the ADC.

Forum Post: RE: TRF3765 and TRF371109 on the same bus

Adam Torma — Fri, 19 Apr 2013 18:21:00 GMT

Eric,

Yes, It is possible to have the TRF3765 and the TRF371109 on the same Serial Peripheral Interface CLK and DATA bus but each must have their own Latch Enable.

Adam

Forum Post: RE: TRF372017EVM stuck on "downloading firmware, please wait"

Joyce Li — Mon, 15 Apr 2013 20:35:00 GMT

Hi Alexander,

You may need to connect the TSW1400 first, start the HSDC Pro GUI before launching any other programs.

Best regards,

Joyce