原标题：ADI AD9208双路14位3GSPS取样ADC评估方案

　　ADI公司的AD9208是双路14位3GSPS取样的模数转换器(ADC),具有低功耗小尺寸和容易使用等特点,宽输入-3dB带宽9GHz,取样模拟信号高达5GHz,噪音密度−152 dBFS/Hz,工作电压0.975 V, 1.9 V和2.5 V dc,双ADC核具有多级差分流水线型架构,ADC数据输出直接连接到四个数字下转换器(DDC),主要用在仪器仪表和测量,频谱/信号和网络分析,数据采集,电子测试和测量,通信和无线基础设施,宽带RF信号处理,软件定义无线电和航空航天和防务以及雷达等.本文介绍了AD9208产品亮点和主要特性,功能框图,以及评估板AD9208-3000EBZ主要特性,电路图和材料清单.

　　The AD9208 is a dual, 14-bit, 3 GSPS analog-to-digital converter (ADC). The device has an on-chip buffer and a sample-and- hold circuit designed for low power, small size, and ease of use. This product is designed to support communications applications capable of direct sampling wide bandwidth analog signals of up to 5 GHz. The −3 dB bandwidth of the ADC input is 9 GHz. The AD9208 is optimized for wide input bandwidth, high sampling rate, excellent linearity, and low power in a small package. The dual ADC cores feature a multistage, differential pipelined architecture with integrated output error correction logic. Each ADC features wide bandwidth inputs supporting a variety of user-selectable input ranges. An integrated voltage reference eases design considerations. The analog input and clock signals are differential inputs. The ADC data outputs are internally connected to four digital downconverters (DDCs) through a crossbar mux. Each DDC consists of up to five cascaded signal processing stages: a 48-bit frequency translator (numerically controlled oscillator (NCO)), and up to four half-band decimation filters. The NCO has the option to select preset bands over the general-purpose input/output (GPIO) pins, which enables the selection of up to three bands. Operation of the AD9208 between the DDC modes is selectable via SPI-programmable profiles. In addition to the DDC blocks, the AD9208 has several functions that simplify the automatic gain control (AGC) function in a communications receiver. The programmable threshold detector allows monitoring of the incoming signal power using the fast detect control bits in Register 0x0245 of the ADC. If the input signal level exceeds the programmable threshold, the fast detect indicator goes high. Because this threshold indicator has low latency, the user can quickly turn down the system gain to avoid an overrange condition at the ADC input. In addition to the fast detect outputs, the AD9208 also offers signal monitoringcapability. The signal monitoring block provides additional information about the signal being digitized by the ADC. The user can configure the Subclasss 1 JESD204B-based high speed serialized output in a variety of one-lane, two-lane, four- lane, and eight-lane configurations, depending on the DDC configuration and the acceptable lane rate of the receiving logic device. Multidevice synchronization is supported through the SYSREF± and SYNCINB± input pins. The AD9208 has flexible power-down options that allow significant power savings when desired. All of these features can be programmed using a 3-wire serial port interface (SPI). The AD9208 is available in a Pb-free, 196-ball BGA, specified over the −40°C to +85°C ambient temperature range. This product is protected by a U.S. patent. Note that throughout this data sheet, multifunction pins, such as FD_A/GPIO_A0, are referred to either by the entire pin name or by a single function of the pin, for example, FD_A, when only that function is relevant.

　　AD9208产品亮点:

　　1. Wide, input −3 dB bandwidth of 9 GHz supports direct radio frequency (RF) sampling of signals up to about 5 GHz.

　　2. Four integrated, wideband decimation filter and NCO blocks supporting multiband receivers.

　　3. Fast NCO switching enabled through the GPIO pins.

　　4. A SPI controls various product features and functions to meet specific system requirements.

　　5. Programmable fast overrange detection and signal monitoring.

　　6. On-chip temperature diode for system thermal management.

　　7. 12 mm × 12 mm, 196-ball BGA.

　　AD9208主要特性:

　　JESD204B (Subclass 1) coded serial digital outputs

　　Support for lane rates up to 16 Gbps per lane

　　1.65 W total power per channel at 3 GSPS (default settings)

　　Performance at −2 dBFS amplitude, 2.6 GHz input

　　SFDR = 70 dBFS

　　SNR = 57.2 dBFS

　　Performance at −9 dBFS amplitude, 2.6 GHz input

　　SFDR = 78 dBFS

　　SNR = 59.5 dBFS

　　Integrated input buffer

　　Noise density = −152 dBFS/Hz

　　0.975 V, 1.9 V, and 2.5 V dc supply operation

　　9 GHz analog input full power bandwidth (−3 dB)

　　Amplitude detect bits for efficient AGC implementation

　　2 integrated, wideband digital processors per channel

　　48-bit NCO

　　4 cascaded half-band filters

　　Phase coherent NCO switching

　　Up to 4 channels available

　　Serial port control

　　Integer clock with divide by 2 and divide by 4 options

　　Flexible JESD204B lane configurations

　　On-chip dither

　　AD9208应用:

　　Diversity multiband and multimode digital receivers

　　3G/4G, TD-SCDMA, W-CDMA, and GSM, LTE, LTE-A

　　Electronic test and measurement systems

　　Phased array radar and electronic warfare

　　DOCSIS 3.0 CMTS upstream receive paths

　　HFC digital reverse path receivers

　　图1. AD9208功能框图

　　评估板AD9208-3000EBZ

　　This user guide describes the AD9208-3000EBZ evaluation board which provides all of the support circuitry required to operate the ADC in its various modes and configurations. This guide entails both the hardware and software setup needed to acquire data capture from the evaluation board. This guide assumes the usage of the accompanying ADS7-V2 EBZ High Speed Evaluation Board. The user guide for the ADS7-V2 provides additional information available for consultation during usage. Documents and software tools, where available, can be found at the HS-ADC Eval Board homepage.

　　The AD9208-3000EBZ supports the AD9208-3000, a 14-bit, 3GSPS dual analog-to-digital converter (ADC). The device has an on-chip buffer and a sample-and-hold circuit designed for low power, small size, and ease of use. This device is designed support direct RF sampling analog signals of up to 5 GHz. The 3 dB bandwidth of the ADC input is greater than 9 GHz. The AD9208 is optimized for wide input bandwidth, high sampling rate, excellent linearity, and low power in a small package.

　　This reference design provides all of the support circuitry required to operate the ADC in its various modes and configurations. It is designed to interface directly with the ADS7-V2EBZ data capture card, allowing users to download captured data for analysis. The device control and subsequent data analyses can now be done using the ACE software package.

　　图2.评估板AD9208-3000EBZ外形图(正面)

　　图3.评估板AD9208-3000EBZ外形图(背面)

　　评估板AD9208-3000EBZ主要特性:

　　Full featured evaluation board for the AD9208-3000EBZ.

　　JESD204B coded serial digital outputs with support for lane rates up to 16Gbps/lane.

　　Wide full power bandwidth supports IF sampling of signals up to 9GHz (-3dB point).

　　Four Integrated wide-band decimation filter and NCO blocks supporting multi-band receivers.

　　Fast NCO switching enabled through GPIO pins.

　　Flexible SPI interface controls various product features and functions to meet specific system requirements.

　　Programmable fast over range detection and signal monitoring.

　　On-chip temperature diode for system thermal management.

　　评估板AD9208-3000EBZ材料清单见:

      评估板AD9208-3000EBZ材料清单.xls

　　详情请见:

      AD9208.pdf