AD7691BCPZRL7:  18位、1.5 LSB INL、250 kSPS PulSAR(R)差分ADC,采用MSOP或QFN封装
     AD7691是一款18位、电荷再分配、逐次逼近型模数转换器(ADC),采用2.3 V至5   V单电源(VDD)供电。该器件内置一个低功耗、高速、18位无失码采样ADC、一个内部转换时钟和一个多功能串行接口端口。在CNV上升沿,该器件对IN+与IN-引脚之间的电压差进行采样。这两个引脚上的电压摆幅通常在0   V至REF之间、相位相反。基准电压(REF)由外部提供。最高可设置为电源电压,其功耗和吞吐量呈线性变化关系。
     SPI兼容串行接口还能够利用SDI输入,将几个ADC以菊花链形式连结到单三线式总线上,并提供一个可选的忙闲指示。采用独立电源VIO时,该器件与1.8V、2.5V、3V或5V逻辑兼容。AD7691采用10引脚MSOP封装或10引脚QFN(LFCSP)封装,工作温度范围为-40°C至+85°C。
     The AD7691 is an 18-bit, charge redistribution, successive approximation,   analog-to-digital converter (ADC) that operates from a single power supply, VDD,   between 2.3 V and 5 V. It contains a low power, high speed, 18-bit sampling ADC with no missing codes, an internal conversion clock, and a versatile serial   interface port. On the CNV rising edge, it samples the voltage difference   between the IN+ and IN- pins. The voltages on these pins usually swing in   opposite phase between 0 V and REF. The reference voltage, REF, is applied   externally and can be set up to the supply voltage.Its power scales linearly with throughput.
     The SPI-compatible serial interface also features the ability, using the SDI   input, to daisy-chain several ADCs on a single 3-wire bus and provides an   optional busy indicator. It is compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic,   using the separate VIO supply.The AD7691 is housed in a 10-lead MSOP or a 10-lead QFN (LFCSP) with   operation specified from -40°C to +85°C.
     产品应用领域 Applications
     
       - 电池供电设备 
 
       - 数据采集 
 
       - 地震数据采集系统 
 
       - 仪器仪表 
 
       - 医疗仪器
 
     
     产品应用领域 Applications
     
       - Battery-powered equipment 
 
       - Data acquisitions 
 
       - Seismic data acquisition systems 
 
       - Instrumentation 
 
       - Medical instruments 
 
     
     AD7691BCPZRL7        特点
     
       - 18位分辨率、无失码 
 
       - 吞吐量: 250 kSPS 
 
       - 积分非线性(INL):典型值±0.75 LSB,
         最大值±1.5 LSB(FSR的±6 ppm)  
       - 动态范围:102 dB(典型值、250 kSPS) 
 
       - 过采样动态范围:125 dB (1 kSPS) 
 
       - 无噪声编码分辨率:20 bits (1 kSPS) 
 
       - 有效分辨率:22.7 bits(1 kSPS) 
 
       - 信纳比(SINAD):
         101.5 dB(典型值、1 kHz)  
       - 总谐波失真(THD):
         -125 dB(典型值、1 kHz)  
       - 真差分模拟输入范围:
         ±VREF 0 V ~   VREF
         (两个输入脚的VREF最高为VDD)  
       - 无流水线延迟 
 
       - 单电源工作:2.3 V至5 V,含1.8 V/2.5 V/3 V/5 V逻辑接口 
 
       - 串行接口:
         SPI-/QSPITM-/MICROWIRETM-/DSP-兼容  
       - 能够以菊花链形式联接多个ADC 
 
       - 可选的忙闲指示功能 
 
       - 功耗:
         1.35 mW @ 2.5 V/100 kSPS, 4 mW @ 5 V/100 kSPS
         1.4 μW @ 2.5 V/100   SPS  
       - 待机电流:1 nA 
 
       - 10引脚封装:MSOP(MSOP-8尺寸)和3 mm × 3 mm QFN (LFCSP)(SOT-23尺寸) 
 
       - 与18位AD7690和16位AD7693、AD7688、AD7687引脚兼容
 
       - 18-bit resolution with no missing codes 
 
       - Throughput: 250 kSPS 
 
       - INL: ±0.75 LSB typical, ±1.5 LSB maximum (±6 ppm of FSR) 
 
       - Dynamic range: 102 dB typical @ 250 kSPS 
 
       - Oversampled dynamic range: 125 dB @1 kSPS 
 
       - Noise-free code resolution: 20 bits @ 1 kSPS 
 
       - Effective resolution: 22.7 bits @ 1 kSPS 
 
       - SINAD: 101.5 dB typical @ 1 kHz 
 
       - THD: -125 dB typical @ 1 kHz 
 
       - True differential analog input range: ±VREF 0 V to   VREF with VREF up to VDD on both inputs 
 
       - No pipeline delay 
 
       - Single-supply 2.3 V to 5 V operation with 1.8 V/2.5 V/3 V/5 V logic   interface 
 
       - Serial interface SPI-/QSPITM-/MICROWIRETM-/DSP-compatible 
 
       - Ability to daisy-chain multiple ADCs 
 
       - Optional busy indicator feature 
 
       - Power dissipation
         1.35 mW @ 2.5 V/100 kSPS, 4 mW @ 5 V/100 kSPS
         1.4 μW   @ 2.5 V/100 SPS  
       - Standby current: 1 nA 
 
       - 10-lead packages: MSOP (MSOP-8 size) and 3 mm × 3 mm QFN (LFCSP) (SOT-23   size) 
 
       - Pin-for-pin compatible with the18-bit AD7690 and 16-bit AD7693, AD7688, and   AD7687     
 
     
     AD7691BCPZRL7                                     功能框图
     
 
     AD7691  产品选型
     
     AD7691BCPZRL7 应用技术支持与电子电路设计开发资源下载
     
       - AD7691 数据手册DataSheet下载. pdf 
 
       - Analog Devices, Inc.ADI 美国模拟器件公司产品订购手册 .PDF
 
       - ADC模数转换器选型指南 . PDF