原标题：ADI AD4114单电源多路24位Sigma－Delta ADC解决方案

　　ADI公司的AD4114单电源低功耗低噪音多路24位Sigma-Delta(Σ-Δ)模拟数转换器(ADC),集成了用于差分或单端高阻抗(≥1 MΩ)双极±10 V电压输入的模拟前端(AFE).此外,AD4114集成了主要模拟和数字信号调理区块,用来配置八个单独建立的每一个模拟输入通路. AD4114具有最大通路扫描速率6.21 kSPS (161 μs),用于全确定的数据.其嵌入的2.5V低飘移(±5 ppm/C)带宽基准电压(带输出基准缓冲器),从而降低了外接元件数量.数字滤波器允许灵活设定,包括在27.27 SPS输出数据速率的50Hz和60Hz的抑制.用户可根据应用每路的要求来选择不同滤波器的设定.器件具有快速和灵活的输出速率,从1.25 SPS 到 31.25 kSPS,每路20SPS时的50Hz和60Hz的共模抑制比为120dB.电源电压AVDD = 3.0 V to 5.5 V ,IOVDD = 2 V to 5.5 V.总电流消耗AVDD + IOVDD (IDD) = 3.9 mA,温度范围从−40C 到 +105C,3线或4线串行数字接口.主要用在过程控制,可编逻辑控制器(PLC)和分布控制系统(DCS)模块以及仪器和仪表.本文介绍了AD4114主要特性,功能框图, 评估板EVAL-AD4114SDZ主要特性,框图,电路图,材料清单和PCB设计图.

　　Single Supply, Multichannel, 31.25 kSPS, 24-Bit, Sigma-Delta ADC with ±10 V Inputs

　　The AD4114 is a low power, low noise, 24-bit, sigma-delta (Σ-Δ) analog-to-digital converter (ADC) that integrates an analog front end (AFE) for fully differential or single-ended, high impedance (≥1 MΩ), bipolar, ±10 V voltage inputs. The AD4114 integrates key analog and digital signal conditioning blocks to configure eight individual setups for each analog input channel in use. The AD4114 features a maximum channel scan rate of 6.21 kSPS (161 μs) for fully settled data. The embedded 2.5 V, low drift (±5 ppm/C), band gap internal reference (with output reference buffer) reduces the external component count. The digital filter allows flexible settings, including simultaneous 50 Hz and 60 Hz rejection at a 27.27 SPS output data rate. The user can select different filter settings depending on the requirements of each channel in the application. The automatic channel sequencer enables the ADC to switch through each enabled channel. The precision performance of the AD4114 is achieved by integrating the proprietary iPassives® technology from Analog Devices, Inc. The AD4114 is factory calibrated to achieve a high degree of specified accuracy. The AD4114 operates with a single power supply that allows simplified use in galvanically isolated applications. The specified operating temperature range is −40C to +105C. The AD4114 is housed in a 40-lead, 6 mm × 6 mm LFCSP.

　　AD4114主要特性:

　　24-bit ADC with integrated AFE

　　Fast and flexible output rate: 1.25 SPS to 31.25 kSPS

　　Channel scan data rate of 6.21 kSPS per channel (161 μs settling)

　　17.3 noise free bits at 1007 SPS per channel

　　120 dB common mode rejection of 50 Hz and 60 Hz at 20 SPS per channel

　　±10 V inputs, either 8 differential or 16 single-ended

　　VIN pin absolute maximum rating: ±65 V

　　Absolute input pin voltage up to ±20 V

　　Minimum 1 MΩ impedance

　　0.07% TUE at 25C

　　On-chip 2.5 V reference

　　±0.12% initial accuracy at 25C, ±5 ppm/C (typical) drift

　　Internal or external clock

　　Power supplies

　　AVDD = 3.0 V to 5.5 V

　　IOVDD = 2 V to 5.5 V

　　Total current consumption AVDD + IOVDD (IDD) = 3.9 mA

　　Temperature range: −40C to +105C

　　3-wire or 4-wire serial digital interface (Schmitt trigger on SCLK) SPI, QSPI, MICROWIRE, and DSP compatible

　　AD4114应用:

　　Process control

　　Programmable logic controller (PLC) and distributed control system (DCS) modules

　　Instrumentation and measurement

　　图1. AD4114功能框图

　　评估板EVAL-AD4114SDZ

　　The EVAL-AD4114SDZ is a full featured evaluation board that can evaluate all the features of the AD4114. The AD4114 is a 24-bit, 31.25 kSPS, Σ-Δ analog-to-digital converter (ADC) with a ±10 V input voltage range (16 single-ended channels or eight fully differential channels). All channels have on-board overvoltage and overcurrent protection.

　　The EVAL-AD4114SDZ includes voltage references and power and data insulation and can be connected to the Analog Devices, Inc., system demonstration platform (SDP) hardware. The SDP board provides connection to a PC via a universal serial bus (USB) port and can provide power for the EVAL-AD4114SDZ from the PC USB port.

　　The AD411x Eval+ evaluation software configures the AD4114 functionality and provides dc time domain analysis in the form of waveform graphs, histograms, and associated noise analysis for ADC performance evaluation.

　　Full specifications for the AD4114 are available in the AD4114 data sheet, which must be consulted in conjunction with this user guide when working with the EVAL-AD4114SDZ.

　　评估板EVAL-AD4114SDZ主要特性:

　　Fully featured evaluation board for the AD4114

　　PC software for control and data analysis (time domain)

　　评估板EVAL-AD4114SDZ包括:

　　EVAL-AD4114SDZ evaluation board

　　AD411x Eval+ evaluation software

　　Plastic screw and washer set

　　图2. 评估板EVAL-AD4114SDZ外形图

　　图3. 评估板EVAL-AD4114SDZ框图

　　图4. 评估板EVAL-AD4114SDZ电路图(1):AD4114

　　图5. 评估板EVAL-AD4114SDZ电路图(2):电压输入前端

　　图6. 评估板EVAL-AD4114SDZ电路图(3):SDP和Arduino连接器

　　图7. 评估板EVAL-AD4114SDZ电路图(4):隔离和电源