原标题：TI ADC12J4000 12位4GSPS取样模数转换解决方案

　　TI公司的ADC12J4000是低功耗12位4GSPS RF取样模数转换器(ADC),具有JESD204B接口,输入高于2.7GHz时有极好的噪音和线性度,最大取样速率4000MSPS,DDC输出字宽 15位复数(总数30位),噪音水平-149 dBFS/Hz或-150 dbm/Hz,主要用在多标准3G和4G通信系统,RF取样SDR,宽带微波骨干网,军用通信, SIGINT, RADAR和LIDAR以及宽带通信系统, 测试测量.本文介绍了ADC12J4000主要特性, ADC12J4000框图以及评估板ADC12J4000EVM主要特性.测试框图,电路图,材料清单和PCB元件布局图.

　　The ADC12J4000 device is a wideband sampling and digital tuning device. The core technology contained in the device is Texas Instruments’ giga-sample analog-to-digital converter (ADC) technology that enables a large block of frequency spectrum to be sampled directly at RF. This technology is combined with low-power digital-processing blocks that provide digital filtering and down-conversion.The selected frequency block is made available on a JESD204B serial interface that is compatible with downstream system-processing elements. Data is output as baseband 15-bit complex information for ease of downstream processing. Based on the digital down-converter (DDC) decimation and link output rate settings, this data is output on 1 to 8 lanes of the serial interface.

　　A DDC bypass mode allows the full rate 12-bit raw ADC data to also be output. This mode of operation requires 8 lanes of serial output.

　　Clear advantages of the ADC12J4000 device over existing solutions currently available on the market are scalability, cost per radio path, power consumption per radio path, and flexibility.

　　The ADC12J4000 device is available in a 68 terminal QFN package. The device operates over the Industrial (–40℃ ≤ TA ≤ 85℃) ambient temperature range.

　　ADC12J4000主要特性:

　　Excellent Noise and Linearity up to and beyond FIN = 2.7 GHz

　　Configurable DDC

　　Decimation Factors from 4 to 32 (Complex Baseband Out)

　　Raw Output Bandwidth of 1000 MHz at 4x Decimation and 4000 MSPS

　　Raw Output Bandwidth of 125 MHz at 32x Decimation and 4000 MSPS

　　Bypass Mode for Full Bandwidth Data

　　Low Pin-Count-Configurable JESD204B Output Interface

　　Automatically Optimized Output Lane Count

　　Embedded Low Latency Signal Range Indication

　　Low Power Consumption

　　ADC12J4000主要指标:

　　Max Sampling Rate: 4000 MSPS

　　Min Sampling Rate: 1000 MSPS

　　DDC Output Word Size: 15-Bit Complex (30 bits total)

　　Bypass Output Word Size: 12-Bit Offset Binary

　　Noise Floor: −149 dBFS/Hz or −150 dbm/Hz

　　IMD3: −64 dBc (FIN = 2670 MHz ± 2.5 MHz at −10 dBFS)

　　FPBW (–3 dB): 3.3 GHz

　　NPR: 48.5 dB

　　Supply Voltages: 1.9 and 1.2 V

　　Power Consumption

　　Bypass (4000 MSPS): 2.0 W

　　Decimate by 10 (4000 MSPS): 2 W

　　Power Down Mode: 10 mW

　　ADC12J4000应用:

　　• Multi-Standard 3G and 4G Communication Receivers

　　• RF-Sampling Software Defined Radio

　　• Wideband Microwave Backhaul

　　• Military Communications

　　• SIGINT

　　• RADAR and LIDAR

　　• Wideband Communications

　　• Test and Measurement

　　图1. ADC12J4000框图

　　评估板ADC12J4000EVM

　　The ADC12J4000EVM is an evaluation module (EVM) that allows for the evaluation of Texas Instruments’ ADC12J4000. The ADC12J4000 is a low power, 12-bit, 4-GSPS RF-sampling analog to digital converter (ADC) with a buffered analog input, integrated Digital Down Converter with programmable NCO and Decimation settings (including un-decimated 12 bit ADC output) and features a JESD204B interface. The EVM has a transformer coupled analog input to accommodate a wide range of signal sources and frequencies. An LMX2581 clock synthesizer and LMK04828 JESD204B clock generator are included on the EVM and can be configured to provide an ultra-low-jitter ADC Device Clock and SYSREF for a complete JESD204B subclass 1 clocking solution.

　　The ADC12J4000, LMX2581 and LMK04828 are controlled through an easy to use software GUI to enable quick configuration for a variety of uses.

　　The ADC12J4000EVM connects directly to the TSW14J56EVM data capture hardware via the high speed FMC connector. The High Speed Data Converter Pro Software is also available for data capture and analysis support when using the TSW14J56EVM.

　　评估板ADC12J4000EVM 主要特性:

　　Flexible transformer coupled analog input and clock input to allow for a variety of sources and frequencies

　　Easy to use software GUI to configure the ADC12J4000, LMX2581 and LMK04828 for a variety of configurations through a USB interface

　　Quickly evaluate ADC performance through High Speed Data Converter Pro software

　　Simple connection to TSW14J56EVM data capture card

　　图2. 评估板ADC12J4000EVM外形图

　　图3. 评估板ADC12J4000EVM测试框图