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[原创] Linear LTC2508-32 32位过取样ADC解决方案

关键词:工业仪表 自动测试(ATE) LTC2508

时间:2017-06-22 12:48:16       作者:Linear       来源:中电网

Linear公司的LTC2508-32是带可配置数字滤波器的 32位过取样ADC,具有低噪音低功耗和高性能等特性,工作电压2.5V,差分全输入范围±VREF,而VREF从2.5V到5.1V.器件具有±0.5ppm INL (典型),1Msps时的SNR为104dB,61sps时的动态范围148dB,保证32位不丢失码.主要用在地震学,能源勘探,自动测试(ATE)和高精度仪表.本文介绍了LTC2508-32主要特性,框图,应用电路图和演示板DC2222A主要特性,电路图,材料清单和PCB设计文件图.

The LTCR2500-32 is a low noise, low power, high performance32-bit ADC with an integrated configurable digitalfilter. Operating from a single 2.5V supply, the LTC2500-32 features a fully differential input range up to ±VREF,withVREF ranging from 2.5V to 5.1V. The LTC2500-32 supportsa wide common mode range from 0V to VREF simplifyinganalog signal conditioning requirements.

The LTC2500-32 simultaneously provides two outputcodes: (1) a 32-bit digitally filtered high precision lownoise code, and (2) a 32-bit no latency composite code.

The configurable digital filter reduces measurement noiseby lowpass filtering and down-sampling the stream of datafrom the SAR ADC core, giving the 32-bit filtered output code.The 32-bit composite code consists of an overrangedetection bit, a 24-bit code representing the differentialinput voltage and a 7-bit code representing the commonmode input voltage. The 32-bit composite code is availableeach conversion cycle, with no cycle of latency.

The digital filter is highly configurable through the SPIcompatibleinterface and features many distinct filter typesthat suit a variety of applications. The digital lowpass filterrelaxes the requirements for analog anti-aliasing. MultipleLTC2500-32 devices can be easily synchronized usingthe SYNC pin

LTC2508-32主要特性:

±0.5ppm INL (Typ)
104dB SNR (Typ) at 1Msps
148dB Dynamic Range (Typ) at 61sps
Guaranteed 32-Bits No Missing Codes
Configurable Digital Filter with Synchronization
Relaxed Anti-Aliasing Filter Requirements
Dual Output 32-Bit SAR ADC
32-Bit Digitally Filtered Low Noise Output
24-Bit Differential + 7-Bit Common Mode 1MspsOutput with Overrange Detection
Wide Input Common-Mode Range
Guaranteed Operation to 85°C
1.8V to 5V SPI-Compatible Serial I/O
Low Power: 24mW at 1Msps
24-Lead 7mm × 4mm DFN Packages

LTC2508-32应用:

Seismology
Energy Exploration
Automatic Test Equipment
High Accuracy Instrumentation

图1.LTC2508-32框图

图2.LTC2508-32应用电路图

演示板DC2222A

Demonstration circuit 2222A features the LTC®2500-32,LTC2508-32 and LTC2512-24 ADCs. The LTC2500-32,LTC2508-32 and LTC2512-24 are low power, low noise,high speed, 32-bit/24-bit SAR ADCs with an integrated configurabledigital averaging filter that operate from a single2.5V supply. The following text refers to the LTC2508-32but applies to all parts, the only difference being samplerate and number of bits. The DC2222A demonstrates theDC and AC performance of the LTC2508-32 in conjunctionwith the DC590 or DC2026 QuikEval™ and DC890 PScope™data collection boards. Use the DC590 or DC2026 todemonstrate DC performance such as peak-to-peak noiseand DC linearity. Use the DC890 if precise sampling ratesare required or to demonstrate AC performance such asSNR, THD, SINAD and SFDR. The DC2222A is intendedto show recommended grounding, component placementand selection, routing and bypassing for this ADC.


图3.演示板DC2222A连接图

图4. 演示板DC2222A-A电路图(1)

图5. 演示板DC2222A-A电路图(2)

图6. 演示板DC2222A-A电路图(3)

图7. 演示板DC2222A-B电路图(1)

图8. 演示板DC2222A-B电路图(2)

图9. 演示板DC2222A-B电路图(3)

图10. 演示板DC2222A-C电路图(1)

图11. 演示板DC2222A-C电路图(2)

图12. 演示板DC2222A-C电路图(3)

图13. 演示板DC2222A-C PCB设计图(1)

图14. 演示板DC2222A-C PCB设计图(2)

图15. 演示板DC2222A-C PCB设计图(3)
演示板DC2222A材料清单见:
715-DC2222A_REV07_WEB_BOM.xls
演示板DC2222A-C PCB设计文件见:
DC2222A.zip
详情请见:
http://cds.linear.com/docs/en/datasheet/250032f.pdf
http://cds.linear.com/docs/en/demo-board-manual/dc2222afa.pdf
以及http://cds.linear.com/docs/en/demo-board-schematic/DC2222A_REV07_PCA_SCHEMATIC.PDF
dc2222afa.pdf
DC2222A_REV07_PCA_SCHEMATIC.PDF

 

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