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Differential Fanout Buffers and Dividers by IDT



Overview of IDT’s differential fanout buffers and differential fanout dividers. Fanout buffers are a useful building block of many clock trees, providing signal buffering and multiple low-skew copies of the input signal. The clock fanout from a single input reduces loading on the preceding driver and provides an efficient clock distribution network. Presented by Vik Chaudhry, technical marketing manager at IDT. For more information about IDT’s rich portfolio of clock IC timing solutions, visit



Thank you for joining us for an overview of IDT’s fanout buffers. My name is Vik Chaudhry, I’m Marketing Manager for IDT’s timing products.
Differential signals are becoming very popular these days for the high speed applications. Various differential levels, such as LVDS, LVPECL and HCSLs are supported by IDT buffers. We offer parts that have up to 24 different outputs, and which go up to 3GHz in speed. These parts are available in both industrial, as well as commercial temperature ranges.  As I mentioned earlier, these parts are designed for very low additive phase noise in mind. You’ll find that additive phase noise is listed in the ACs tables in the back of the data sheets, and in many cases, you will also see a phase noise plot in the back of the data sheets, too. Here’s an example of 853S006 device, which has one input and six outputs. In this slide, you can also see the additive phase noise for this device.
Here are some more examples of differential buffers. One important thing to note is that in these cases, one, the input level is single ended, so the device acts as a level translator. Second, that these devices have a MUX built into them. In one case we have two single ended signals coming in. And in the other case, we have LVCMOS input and a crystal input. Also worth noting is that all output signals are synchronized for the enable signal, so they are all phased aligned.
854105 is another example of a simple one to four buffer, which has individual output enabled pins. 879S216 as you can see on the bottom of the screen, has a MUX divider and fanout buffer, all combined into one flexible device. Such devices can not only provide the fanout, but in some cases they can build the whole product tree for a customer.
IDT has a very large portfolio of fanout and clock distribution devices. To make it easy to select these parts, we have developed the collateral that can be used. This collateral is located on the IDT website under clock and timing products. If you look under fanout buffers and dividers, you will see this collateral available.
We also have an excellent application support for all the clocks and clock distribution devices. Most of our products include IBIS models. We also have application notes for various termination schemes, filter recommendations, and we also review schematics. If you have any questions, please feel free to either drop us an email at or
Thank you for choosing IDT timing products.