零延迟缓冲器 (ZDB) 提供了输出端输入时钟的同步拷贝（无传播延迟），并且一般情况下无需转换频率。 Renesas’ 的 ZDB 均是基于 PLL 的器件，可重新生成带扇出的输入时钟信号，以驱动多个负载提供多种信号级，包括 LVPECL、LVDS、HCSL、CML、HSTL、SSTL 或 LVCMOS。 对于 FPGA、CPU、逻辑和同步存储器等需要同步时钟的应用而言，ZDB 是它们的理想选择。

大多数零延迟缓冲器的延迟可通过外部反馈路径进行调节。 这样可以实现对时钟信号到达负载所需计时的精确控制。 当全部输出（包括反馈输出）均采用简单分频器时，可进行简单的频率转换以保持时钟同步化。

提示： 如果需要不止一个唯一的输出频率（如 100MHz 和 125MHz），可使用“输出库”参数选择器。 每个库与唯一的输出频率对应。

业内领先的零延迟缓冲器解决方案

Renesas' 的零延迟缓冲器 (ZDB) 产品系列拥有广泛的选项和功能。 LVPECL、LVDS、HCSL、CML、HSTL、SSTL 和可选输出等差分输出，都支持高达 3.2GHz 的输出频率和频率高达 350MHz 的单端 LVCMOS 输出。 此外，Renesas' 的 PLL 产品组合中有一些器件支持 1.2V 至 5V 电源电压，可在商业和工业温度范围内使用。

使用 Renesas PLL 产品具有多种好处。 减少电路板上石英晶体的数量，从而提高可靠性，因为晶体很容易受到冲击和振动的影响。 使用时钟信号发生器后，通过使用一个器件取代多个晶体和振荡器，还可降低消费类电子产品'的电路板成本和空间、材料单 (BOM) 和库存水平。 对于包括个人电脑、消费类电子产品或工业系统，以及高性能网络和通信系统在内的各种系统而言，它们都是理想选择。

选择零延迟缓冲器 (ZDB)

选择用于特定应用的 ZDB 时要考虑许多重要因素。 用户可以下列参数作为起始点，来缩小潜在解决方案的范围：

  • 输出数量：选择带有足够输出端的 ZDB 来简化您的时钟数。 元件数量减少可简化设计和采购流程，能够更快地投入市场营销，甚至能提高可靠性，从而增加产出。 Renesas 针对高度复杂的系统提供了一些业内’集成度最高的解决方案，同时也针对介于上述两者之间的系统提供了适当的解决方案。
  • 输出类型：零延迟缓冲器所需输出的信号类型。 Renesas 提供 LVPECL、LVDS、HCSL、CML、HSTL、SSTL 或 LVCMOS。
  • 输入/输出频率范围：输入和输出频率的有效范围。 Renesas 提供的零延迟缓冲器可满足所有主流应用的频率需求。
  • 核心电压：向 ZDB 供电的电源电压。 它通常由系统中可用的电源轨决定，并往往会对输出的电压电平产生影响。 Renesas’ 零延迟缓冲器的电压范围为 3.3V 到 1.5V。

时钟和时序

产品选型表

    Processing table
    器件号
    Outputs (#)
    Output Type
    Output Freq Range (MHz)
    Input Freq (MHz)
    Inputs (#)
    Input Type
    Output Banks (#)
    Core Voltage (V)
    Output Voltage (V)
    Divider Value
    9QXL2000B
    20-Output DB2000Q PCIe Clock Buffer    		 20 LP-HCSL 1 - 400 1 - 400 1 HCSL 1 3.3 0.7
    9QXL2000C
    20-Output Enhanced DB2000Q PCIe Clock Buffer    		 20 LP-HCSL 1 - 400 1 - 400 1 HCSL 1 3.3 0.7
    9QXL2001B
    20-Output DB2000QL PCIe Clock Buffer    		 20 LP-HCSL 1 - 400 1 - 400 1 HCSL 1 3.3 0.7
    9QXL2001C
    20-Output Enhanced DB2000QL PCIe Clock Buffer    		 20 LP-HCSL 1 - 400 1 - 400 1 HCSL 1 3.3 0.7
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    文档

    文档标题 类型 日期
    Clock Distribution Overview
    PDF217 KB
    概览
    Zero-Delay Clock Buffers by IDT

    Description

    Brief overview of IDT's zero-delay buffers. Zero-delay buffers (ZDB) are ideal for applications requiring synchronized clocking for FPGAs, CPUs, logic and synchronous memory. Zero-delay buffers are PLL-based devices that regenerate the input clock signal with fanout to drive multiple loads. Most devices allow the delay through the device to be adjusted through an external feedback path. This allows precise control of the timing of the clock signals to the loads. Zero-delay buffers provide a synchronous copy of the input clock at the outputs, usually without frequency translation. Simple frequency translation is possible when a single divider is used for all outputs, including feedback output, to maintain clock synchronization.Presented by Vik Chaudhry, technical marketing manager at IDT. For more information about IDT's rich portfolio of clock IC timing solutions, visit www.idt.com/go/clocks.

     

    Transcript

    Thank you for joining us for an overview of IDT's fanout buffers. My name Vik Chaudhry. I'm Marketing Manager for IDT's timing products. 
     
    We also have zero delay buffers in our portfolio. A zero delay buffer is a PLL-based device that provides an output that is in phase alignment with the input signal. In this category of devices we have parts with multiple outputs, different levels of inputs and outputs, and different divider ratios. Designers like these types of devices when they want really tight control over timing of their board. 
     
    IDT has a very large portfolio of fanout and clock distribution devices. To make it easy to select these parts, we have developed 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 e-mail at tsd-applications@IDT.com or clocks@IDT.com. 
     
    Thank you for choosing IDT timing products.
    Video List
    Zero-Delay Clock Buffers by IDT