# Search results

1. ### Reading list for very high speed PCBs (>7 GHz bandwidth)

Hello, Can you suggest a book/reading material that can teach about how to design high speed PCBs for signal transmission? Due to an unfortunate turn of events, I now have to design PCBs with >7GHz bandwidth per line for fiber-optic front-end interface. Hence I think I have to learn about the...
2. ### CPW simulation in ADS using momentum and co-sim

Hi all, i found some discrepancies when simulating a CPW in ADS momentum compared to when co-simulating in ADS the same layout. Wonders if someone can help clarify things. It's a bit involved so I thank you so very much for your patience. Situation: We are simulating a coplanar waveguide...
3. ### Coplanar waveguide sandwiched between GND and VCC

Hi A question about coplanar waveguides (CPW). A conventional CPW structure is a signal line sandwiched between two ground tracks. Can we get the same characteristic impedance if we sandwich a signal line with the same dimensions between a GND track and a VCC (some DC supply voltage, say +5V)...
4. ### Is the S21 plot result given in the voltage ratio or the power ratio in ADS Momentum?

Hi, Just a simple question. Is the S21 plot result we get from momentum in dB the voltage ratio or the power ratio? Is there a method to convert one to another in ADS? Thanks!
5. ### Refractive index of solder mask

Hello, Does anyone know what's the typical refractive index of a green solder solder mask material? Guess that this is not a typical question but we need the value for some optical system design. Cant seem to get the value from web. Thnx!
6. ### Stiff PCB material with similar dielectric constant as FR4

Hi all, My 1 mm FR4 board warps all over the place when heated. Do u know of a cheap PCB substrate with similar dielectric constant to FR4 but is stiffer? Thanks
7. ### very low noise 3.3 V voltage regulator

Hi, At the moment I am trying to design a very low noise power supply for a 7GHz comms circuit. The best power design I got is based on ADP3338 attached below. The circuits require 3.3V and takes in 150 mA current max. The smaller the voltage regulator circuit is, the better. Have u got a...
8. ### SNR - peak-to-peak or RMS?

Hi, Hope someone can help me with the definition of signal-to-noise ratio (SNR). On the last page of this document: https://pdfserv.maxim-ic.com/en/an/AN607.pdf it is said that SNR is the ratio of the peak-to-peak signal and the rms noise However, wikipedia...
9. ### Output impedance matching question

Output impedance Hi I came across this voltage source (attached below) but i am unsure what its output impedance is. Is it 50 Ohm and hence must be matched with 50 ohm transmission line and load? How do we proof its output impedance mathematically? thanks in advance!
10. ### parasitic extraction from PCB layout

hi is there a software that can extract parasitics (LRC parameters) given a PCB layout? thanks
11. ### High frequency noise for 10 Gbps circuit

Hi, I am designing a 10 Gbps laser driver using commercially available ICs. At the moment, I noticed that there is significant noise in the resulting eye diagram. This noise is reduced when I touch the circuit (to be precise, the interface line between the IC and the laser) with my bare hands -...
12. ### ARES Footprints libraries repository needed

footprints ares Hi, Are there ares footprint libraries out there that we can download for components not included in the standard package? Thanks in advance, Fendi
13. ### Help with ARES: Rotating region file before pasting

Hi, I saved a portion of my PCB into a region file and would like to paste this into another PCB layout. I need to rotate the region file somehow before pasting it. How can this be done? If there's another way to cut and paste one layout into another with a rotation feature, please tell me...