NS LMK04800双回路PLL低噪音时钟抖动清理方案

NS 公司的LMK04800系列是双回路PLL的低噪音时钟抖动清理器，具有超低的RMS抖动性能：12 kHz -20 MHz为111fs RMS，100 Hz - 20 MHz为123fs RMS，工作电压3.15 V 到 3.45 V，时钟速率高达1536 MHz，可以满足新一代系统所需的要求，主要用在数据转换器时钟/无线基础设备，网络， SONET/SDH, DSLAM，医疗/视频/军用/航天以及测试测量设备。本文介绍了LMK04800主要特性，详细方框图和多种模式下的功能方框图以及典型应用电路。

LMK04800 Family Low-Noise Clock Jitter Cleaner with Dual Loop PLLs

The LMK04800 family is the industry’s highest performance clock conditioner with superior clock jitter cleaning, generation, and distribution with advanced features to meet next generation system requirements. The dual loop PLLatinum ™ architecture enables 111 fs rms jitter (12 kHz to 20 MHz) using a low noise VCXO module or sub-200 fs rms jitter (12 kHz to 20 MHz) using a low cost external crystal and varactor diode.

The dual loop architecture consists of two high-performance phase-locked loops (PLL), a low-noise crystal oscillator circuit, and a high-performance voltage controlled oscillator(VCO). The first PLL (PLL1) provides a low-noise jitter cleaner function while the second PLL (PLL2) performs the clock generation.
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