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IDT VersaClock ® 3 : Introduction to Software and Evaluation Board



This video provides and overview of IDT’s VersaClock® 3 and VersaClock LP product families. VersaClock programmable clock generators allow designers to save board space and cost by replacing crystals, oscillators (including programmable oscillators), and buffers with a single timing device. IDT’s VersaClock product portfolio contains parts with up to four internal PLLs, each individually programmable, allowing for up to seven unique frequencies. Various subsets of the VersaClock family are targeted for different applications. For high-reliability systems, the VersaClock III family supports glitchless automatic or manual switchover function allows the redundant clock to be selected during normal operation. For consumer systems, VersaClock III and LP (low power) provide flexibility with an internal EEPROM that makes it simple to reprogram frequencies for changing system requirements through the use of the I2C interface. Presented by Baljit Chandhoke, Product Marketing Manager at Integrated Device Technology, Inc. To learn more about IDT’s VersaClock programmable clock generators, visit


Hello. Today I’m going to be providing an introduction to the VersaClock III family of programmable timing solutions from IDT, an introduction to how to download our software, use our software, and using our evaluation boards, as well as socket daughter cards for programming loose parts on your bench. 
The VersaClock III family of programmable devices is our third generation family, providing improved jitter performance, lower power consumption, availability of single-ended as well as differential output frequencies and provides increased user flexibility using our software interface. 
Our VersaClock III family actually has a dedicated website on The way to get there is to type in From this website, you can see we have all information related to the VersaClock III family. We have brief descriptions, the feature sets available, all of the product matrices involved including our crystal oscillator as well as VCXO solutions, and all of the data sheets, by clicking on the links of the part numbers. Scrolling down the page, you will see our software downloads, user manuals, as well as product collateral, such as our press release, as well as the product flyer. To download the software it is free for all users. All you need is a myIDT account name and password. This is easily attainable from To download the software, simply click on the link, and the pop-up box prompts you. Click “Open” and the software will automatically begin downloading. There are two versions of the software. One is connected to our server at The other is available for use strictly on your computer if you’re not connected to the internet. For that version, I suggest clicking on the second link, and following the same instructions of opening when the pop-up box prompts you. 
After the software is downloaded, an icon will appear on your desktop, and it will also be available in your programs menu. To open the software, all you do is double-click on the icon, and a pop-up box will appear. 
You’ll see that there are two options; one is called local, one is called remote. The local is the desktop version that you downloaded, so if you’re not connected to the internet, I suggest clicking “Local.” From here, all you would need to do is click “OK.” If you want to use the version that’s connected to our server, all you need to do is click on remote, and enter your myIDT username and password, and click OK
Next, the VersaClock III software menu pops up. You’ll see that there are two options available. One is to start a new session, which is this link here. The other is to open a previous session or programming file that you’ve already created and want to modify. Today we’ll focus on introducing a new programming file, so I’ll click on this link. As you see, a pop-up box appears that shows all of the part numbers available using the software interface, as well as a brief feature set of each product, and the package and pin-out. Today, we’ll choose to program a 5V49EE701 7-output VersaClock III clock synthesizer. So scroll down the list and you’ll see that all of the part numbers are available in the VersaClock III family. Choose the product that you’d like to create a programming file, and hit “Continue.” 
Next you will see the general interface for the VersaClock software. We have text fields along the top where you can enter information related to your company, so today I’ll be typing “ABC company,” as well as the operator, the person creating the programming file. Also available is a notes field, so if you want to tag which project this programming file will be used for, for example, “Project A.” Also you will see a part number field that’s automatically populated for the part number that you’ve selected, as well as a file name. The VersaClock software automatically attaches a file name to the programming file that you’re working on. You see that the part number, the package, as well as the date and time stamp. You also have the ability to name the file exactly as you want by hitting “Save As” and renaming the file. Next, you’ll want to enter the input frequency and output frequencies desired from this device. You’ll see here, we have a drop-down menu of all common input frequencies. If you select “25,” for example, to use as an input frequency, as either a clock or crystal input. You also have the ability to manually type in any frequency that you’d like. For the example today I will choose 25 MHz input.
Next, what you’ll want to do is type the desired outputs. So I’ll type 25 MHz reference output, 100 MHz, 100 MHz, 27 MHz, 74.25 MHz, as well as 48 MHz. You’ll see that there is also an input field for error ppm. This is available if you want to enter the tolerance or the ppm error for each clock output. Remember that you also have to take into account the error budget of the input frequency. For example, if you’re using a +/- 50 ppm crystal, you’ll have to account for that in the total error ppm budget. Once you’ve entered in all of your output frequencies desired, simply hit “Calculate,” and the software will automatically configure the PLLs in the chip to optimize for jitter performance and power consumption. 
You will see that the software came up with a zero ppm synthesis error solution for each of the frequency outputs that we have entered.
The VersaClock III family also has the ability to do a differential pair output. In order to do this, we will demonstrate. For example, if you wanted a 100 MHz differential pair, we’ve entered two single-ended frequencies of 100 MHz to begin with. Next, all you would need to do is click on “View,” “Detailed view,” which shows the highly flexible user interface to programming each individual PLL, VCO, loop parameter, and output dividers. We’ll go into the details of using detailed view in a later video. Today for simplicity, we’re just covering an introduction to the manual configuration view. If you scroll to the right, you’ll see that each of the outputs that we’ve calculated are here. Over to the right you’ll see each of the output levels associated with those frequencies. For the two 100 MHz that we would like to compare together to be a differential output, we will simply click on the down box next to the 100 MHz output and choose the level that we would like. For this example, we’ll choose HCSL for a PCI-express gen one pair.
From here, all you would need to do is go back to the single configuration view, and the two 100 MHz outputs are now combined together for a differential pair. You will also see a note in red font at the bottom of the screen indicating that you have changed this output in the detailed view. On the right-hand side of the screen, you will see the pin-out of the part, as well as where the frequencies are located on each of the output pins. You will see that the 25 MHz output is highlighted in blue font. This indicates that the output is a reference frequency from your input of 25 MHz. The software also gives you the ability to force that through a PLL instead of a true reference output. In order to do that, simply click this box under “use PLL” next to the 25 MHz output.
Next we will show you how to add spread spectrum to an output in the VersaClock software. There are two PLLs with spread spectrum capability in this VersaClock III family. In the software you have the ability to choose which frequency to apply spread spectrum to, as well as the modulation frequency associated with each of those. All you would need to do is type in the spread modulation rate that you’d like from the PLL. Anywhere from 32 kHz up to 120 kHz. Next you can choose the direction of the spread spectrum, either down spread or center spread. Since we know that we have a 100 MHz PCI-express, we would like to choose down spread of half a percent. 
Next, we’d like to choose which output to apply these spread spectrum criteria to. So for the 100 MHz outputs, we click on the boxes under A. This applies spread spectrum that we’ve defined for spread spectrum PLL A to the 100 MHz outputs. Next, we’ll hit “calculate” to add that spread spectrum to the 100 MHz output. The software reconfigures each of the PLL parameters with the updated spread spectrum configurations as well as the input and output frequencies we’ve previously defined.
 Here we see that the outputs now appear in magenta color. This indicates that spread spectrum is applied to those outputs. You can also see that over here in the pin mapping section of the user interface. Remember that we also forced the 25 MHz through a PLL instead of giving a reference output. You will see that the 25 MHz now appears in black color indicating that it is not a reference output any more. 
Also on screen you will see that the software has estimated the power consumption of this configuration to be 86 mA. You also see that the modulation rate of 32 kHz and -0.5% down spread is applicable in this setting. Also available in this family of devices are configuration settings. There are 6 configuration settings in each of the VersaClock III products. Here, you can see each of the configurations along the top, which are programmable through hardware select pins noted here. For example, we have already used configuration zero to come up with this sequence of input and output frequencies. By clicking on configuration one, you are able to program the chip with a completely different set of input and output frequencies, effectively generating multi-programs, for different projects, in one piece of silicon.
Another feature of this device is using configurations to do frequency selections or different spread amounts. To demonstrate that, I will click on this button here, which allows you to populate different configurations from previous ones already calculated. For example, for configuration one, if I want to turn spread off on that 100 MHz signal, all I would do is copy from register zero, click “OK,” and all of the information is transferred into configuration one. To turn off spread in this configuration I just un-click the boxes under A, and hit “Calculate.” As you can see, the software has re-calculated with spread turned off. By clicking between zero and one, you can see the difference. Also note that the hardware select pins are changing as well. So, by tying hardware select pin zero hide, you are effectively making spread turn off on the 100 MHz outputs.
To program the device on the evaluation board, all you need to do is plug in the evaluation board to a USB port on your computer. The board registers and is plugged in when you see the red LED light. To program the device on the board, all you would need to do is go to the settings menu, highlight “port,” and ensure the VersaClock III is highlighted in the port. Click “OK,” and then “Program Part,” in the software user interface. The software has successfully programmed the part on the evaluation board.
You can also use the evaluation board to program loose parts on your bench. In order to do so, all you need to do is remove the pins from the header on the evaluation board, and plug in the appropriate socket for the package of the product that you are using. From there, plug the evaluation board back into your computer, and hit “program part” just as you did for the evaluation board.
That concludes our introduction to the VersaClock III family of programmable timing solutions, the software download, using the manual configuration, using the evaluation board as well as our daughter cards for programming loose parts. Thank you for joining us, and tune in soon for our in-depth training, using the detailed view of the VersaClock software.