Silabs Si54x系列超低抖动高性能晶振解决方案详解

Silabs公司的Si54x系列是采用第四代DSPLL技术的超低抖动高性能晶体振荡器，频率范围从0.2-1500MHz，分辨率小于1ppb，具有极好的PSRR，电源抗噪度-80dBc，稳定度3倍于SAW振荡器，工作电压3.3V，2.5V和1.8V，输出格式包括LVPECL， LVDS， CML， HCSL， CMOS和双CMOS输出，主要用在100G/200G/400G OTN，相干光学，10G/40G/100G光学以太网，3G-SDI/12G-SDI/24G-SDI广播视频，数据中心，测量和测试，时钟和数据恢复，FPGA/ASIC时钟。本文介绍了Si54x系列主要特性，功能框图，通用振荡器评估板Si5xxUC-EVB主要特性，框图和电路图。

The Si545 Ultra Series™ oscillator utilizes Silicon Laboratories’advanced 4th generation DSPLL® technology to provide an ultra-low jitter， low phase noise clock at anyoutput frequency. The device is factory-programmed to any frequency from 0.2 to1500 MHz with 《1 ppb resolution and maintains exceptionally low jitter for both integerand fractional frequencies across its operating range. The Si545 offers excellentreliability and frequency stability as well as guaranteed aging performance. On-chippower supply filtering provides industry-leading power supply noise rejection，simplifyingthe task of generating low jitter clocks in noisy systems that use switched-modepower supplies. Offered in industry-standard 3.2x5 mm and 5x7 mm footprints， theSi545 has a dramatically simplified supply chain that enables Silicon Labs to ship customfrequency samples 1-2 weeks after receipt of order. Unlike a traditional XO，where a different crystal is required for each output frequency， the Si545 uses onesimple crystal and a DSPLL IC-based approach to provide the desired output frequency.

This process also guarantees 100% electrical testing of every device. The Si545 isfactory-configurable for a wide variety of user specifications， including frequency， output format， and OE pin location/polarity. Specific configurations are factory-programmedat time of shipment， eliminating the long lead times associated with custom oscillators.

Si54x系列主要特性：

• Available with any frequency from 0.2MHz to 1500 MHz

• Ultra low jitter： 80 fs Typ RMS（12 kHz–20 MHz）

• Excellent PSRR and supply noiseimmunity：–80 dBcTyp

• 3x tighter stability than SAW oscillators

• 3.3 V， 2.5 V and 1.8 V VDD supplyoperation from the same part number

• LVPECL， LVDS， CML， HCSL， CMOS，and Dual CMOS output options

• 3.2×5， 5x7 mm package footprints

• Samples available with 1-2 week leadTimes

Si54x系列应用：

• 100G/200G/400G OTN， coherent optics

• 10G/40G/100G optical ethernet

• 3G-SDI/12G-SDI/24G-SDI broadcastvideo

• Datacenter

• Test and measurement

• Clock and data recovery

• FPGA/ASIC clocking

图1.Si54x系列框图

通用振荡器评估板Si5xxUC-EVB

This document describes operation of the Silicon Laboratories Si5xxUC-EVB evaluation board designed to evaluate any of Silicon Labs’ pin-controlled or I2C configurable Si5xx XOs or VCXOs. Three device sites are available to support one of either 5mm x 7mm， 3.2mm x 5mm， or 2.5mm x 3.2mm devices in either 4， 6， or 8 pin configurations. Selector switches make it easy to configure device control pins （pins 1， 2， 7， or 8） for properoperation without the use of jumpers. Similarly， XO device VDD voltage （3.3V， 2.5V，1.8V） can be selected via switches based on either external +5V （for stand-alone operation）or micro USB sourced +5V USB operation. The EVB also features flexible outputtermination circuits and PCB layout optimized for superior signal integrity.

通用振荡器评估板Si5xxUC-EVB主要特性：

• Evaluation of any Silicon Labs XO orVCXO （Si51x， Si53x， Si54x， Si55x， Si57x，Si59x）

• AC coupled differential/single-ended outputclocks.

• Voltage control （Vc） port for VCXOevalution.

• Switch selectable settings. No jumpers.

• External power or USB powered.

• Use stand-alone or with our ProgrammableOscillator Calculator SW tool

图2.通用振荡器评估板Si5xxUC-EVB外形图

图3.通用振荡器评估板Si5xxUC-EVB框图

图4.通用振荡器评估板Si5xxUC-EVB电路图（1）

图5.通用振荡器评估板Si5xxUC-EVB电路图（2）