>
首页 » 解决方案 » ADI AD7699 SAR 模数转换方案

ADI AD7699 SAR 模数转换方案

作者:  时间:2008-07-21 09:53  来源:eaw
数据采集设计工程师面临的挑战是设计具有最高的精度、最高的集成度以及最低的功耗解决方案,因此多通道ADC已经成为越来越受欢迎的选择。ADI 公司的AD7699 是最快的16位8通道SAR 模数转换器,采样速率500 kSPS,广泛应用在以电池为能源的设备,医疗仪器,移动通信,PDA,数据采集以及过程控制等。本文介绍一系列模数转换器的特性,集中介绍了AD7699的主要性能特点,方框图以及评估板的详细电路图。

多通道ADC降低功耗和空间需求
数据采集设计工程师面临的挑战是设计具有最高的精度、最高的集成度以及最低的功耗解决方案,因此多通道ADC已经成为越来越受欢迎的选择。AD768x 系列14 bit与16 bit ADC不仅能够满足这些需求,而且能够进一步缩短设计周期。AD7699是最快的16 bit、8通道ADC,采样速率500 kSPS。AD7682与AD7689工作电压是2.7 V,以节省功耗。AD7949是低成本的14 bit、8通道ADC。其他系列特性包括:允许单端、差分或双极输入的可配置多路复用器、可选择电压基准(2.5 V或4.096 V)、温度传感器、可选择单极滤波器、允许连续的通道扫描的时序器。适合AD768x系列产品的驱动放大器包括ADA4841-2、AD8021与AD8022。



24位过采样ADC,适合低功耗设备
ADI公司的24位过采样ADC的设计目的是扩展Σ-Δ产品系列,使其速率超过工业类型Σ-Δ ADC的输出数据速率。
这些ADC实现了宽动态范围与输入带宽(如AD7766与AD7767)与适合高端仪器应用的低功耗(如振动分析、声纳与音频)等特性的完美结合。在较大交流或直流信号中测量输入信号的微小变化时,AD776x产品系列是完美的设计选择。 适合AD776x系列的ADI配套产品包括ADA4841,它是低噪声与低失真度、轨对轨输出放大器,以及低功耗、低失真度、高信噪比驱动器放大器ADA4941。

The AD7699 is an 8-channel 16-bit, charge redistribution successive approximation register (SAR), analog-to-digital converter (ADC) that operates from a single power supply, VDD.
The AD7699 contains all of the components for use in a multichannel, low power, data acquisition system including: a true 16-bit SAR ADC with no missing codes; an 8-channel, low crosstalk
multiplexer useful for configuring the inputs as single ended (with or without ground sense), differential or bipolar; an internal low drift reference (selectable 2.5V or 4.096V) and buffer; a temperature sensor; a selectable 1-pole filter; and a sequencer useful when channels are continuously scanned in order.
The AD7699 uses a simple SPI interface for writing to the configuration register and receiving conversion results. The SPI interface uses a separate supply, VIO, which is set to the host logic
level.Power dissipation scales with throughput.
The AD7699 is housed in a tiny 20-lead LFCSP with operation specified from −40°C to +85°C.
AD7699主要特性:
16-bit resolution with no missing codes
4-channel multiplexer with:
Unipolar single ended or
Differential (GND sense)/pseudo-bipolar inputs
Throughput: 500 kSPS
INL/DNL: ±0.6 LSB typical
Dynamic range: 93.5 dB
SINAD: 92.5 dB @ 20 kHz
THD: −100 dB @ 20 kHz
Analog input range:
0 V to VREF with VREF up to VDD
Reference:
Internal selectable 2.5 V/4.096 V or
External buffered (up to 4.096 V)
External (up to VDD)
Internal temperature sensor
Channel sequencer, selectable 1-pole filter, BUSY indicator
No pipeline delay, SAR architecture
Single-supply 5 V operation with
1.8 V to 5 V logic interface
Serial interface SPI®/QSPI/MICROWIRE/DSP compatible
Power dissipation:
6 mW @ 5 V/100 kSPS
Standby current: 1 nA
20-lead 4 mm × 4 mm LFCSP package
主要应用:
Battery-powered equipment
Medical instruments
Mobile communications
Personal digital assitants
Data acquisition
Seismic data acquisition systems
Instrumentation
Process Control



图1. AD7699方框图
The EVAL-AD76XXCB 8/10-Pin is an evaluation board for the AD768x/AD769x/AD794x/AD798x 8 and 10-pin PulSAR high resolution ADCs
评估板主要特性:
Versatile analog signal conditioning circuitry
On-board reference, crystal oscillator and buffers
16-bit Parallel Buffered Outputs
Ideal for DSP and data acquisition card interfaces
Analog and digital prototyping area for breadbording the target system
Stand-alone operation or Eval control board compatibility
PC software for control and data analysis
LabVIEW1 driver to develop custom application



图2.评估板外形图



图3. 评估板电路图(模拟部分)



图4. 评估板电路图(数字部分)



图5. 评估板电路图(电源部分)



图6. 评估板电路图(选择部分)

相关推荐

德州仪器推出业界首款支持 SPICE 模型的 SAR ADC

德州仪器  ADC  SPICE  2012-05-24

美国出口管制条例对于Linear ADC系列重新进行分类

凌力尔特  ADC  2011-12-20

为高速模数转换选择优秀的缓冲放大器

ADC  缓冲放大器  2011-09-16

透视芯海科技在ADC技术上的“穿越”

芯海科技  ADC  CSE7780  2011-09-14

理解Σ-Δ ADC中时钟公差对50Hz/60Hz噪声抑制

ADC  滤波器  2011-09-01

副边变压器端接提升高速ADC的增益平坦度

ADC  变压器  2011-08-31
在线研讨会
焦点