ADN2812是ADI公司生產的一款具有量化接收機功能，信號電平檢測、時鐘和數據恢復功能，連續(xù)數據率從12.3Mb/s到2.7Gb/s。ADN2812芯片在沒有外部基準時鐘或編程的情況下，自動鎖存所有數據速率。滿足所有光纖網絡抖動，包括抖動轉移、抖動生成和抖動公差。本文主要介紹ADN2812的主要特性、方框圖及其應用。同時介紹EVAL-ADN2812EB評估板、電路圖、材料清單和PCB Layout圖。
The ADN2812 provides the receiver functions of quantization, signal level detect, and clock and data recovery for continuous data rates from 12.3 Mb/s to 2.7 Gb/s. The ADN2812 auto-matically locks to all data rates without the need for an external reference clock or programming. All SONET jitter requirements are met, including jitter transfer, jitter generation, and jitter tolerance. All specifications are quoted for −40℃ to +85℃ ambient temperature, unless otherwise noted.
This device, together with a PIN diode and a TIA preamplifier, can implement a highly integrated, low cost, low power fiber optic receiver.
The receiver front end, loss of signal (LOS) detector circuit indicates when the input signal level has fallen below a user-adjustable threshold. The LOS detect circuit has hysteresis to prevent chatter at the output.
The ADN2812 is available in a compact 5 mm × 5 mm 32-lead lead frame chip scale package (LFCSP).
ADN2812主要特性：
Serial data input: 12.3 Mb/s to 2.7 Gb/s
Exceeds SONET requirements for jitter transfer/ generation/tolerance
Quantizer sensitivity: 6 mV typical
Adjustable slice level: ±100 mV
Patented clock recovery architecture
Loss of signal (LOS) detect range: 3 mV to 15 mV
Independent slice level adjust and LOS detector
No reference clock required
Loss of lock indicator
I2C interface to access optional features
Single-supply operation: 3.3 V
Low power: 750 mW typical
5 mm × 5 mm 32-lead LFCSP
ADN2812應用：
SONET OC-1/OC-3/OC-12/OC-48 and all associated FEC rates
Fibre Channel, 2× Fibre Channel, GbE, HDTV
WDM transponders
Regenerators/repeaters
Test equipment
Broadband cross-connects and routers
圖1. ADN2812方框圖
EVAL-ADN2812EB介紹：
This application note describes the use of the EVAL-ADN2812EB. The ADN2812 is a continuous rate clockrecovery, data-retiming device based on a multiloop PLL architecture. The ADN2812 can automatically lock to any data rate from 10 Mbps to 2.7 Gbps, recover the clock, and retime the data without programming and without the need for an external reference clock as an acquisition aid. An I2C“ interface is available to access special features of the ADN2812; however, it is not required for normal operation.
The EVAL-ADN2812EB is fabricated using standard FR-4 materials. All high speed differential signal traces are matched to within 3 mils length and maintain a 50 characteristic impedance to preserve signal integrity.
EVAL-ADN2812EB電路圖：
圖2. EVAL-ADN2812EB電路圖
EVAL-ADN2812EB材料清單：
PCB Layout圖：
