TI公司的ADS5294是80MSPS/14位 8路ADC,具有低功耗,高SNR和低SFDR,以及连续过载恢复,适用于高性能系统设计. ADS5294具有数乁信号处理核,包括数字滤波器模块, 可编程数字增益0 dB到12 dB,内部和外接基准电压,1.8V工作电压,主要用在超声图像,通信设备和多路数据采集.本文介绍了ADS5294主要特性,方框图, 模拟输入模型和电路,评估模块测试图以及评估模块电路图,材料清单和PCB布局图.

　　Using CMOS process technology and innovative circuit techniques, the ADS5294 is a low power 80MSPS 8-Channel ADC. Low power consumption, high SNR, low SFDR, and consistent overload recovery allow users to design high performance systems.

　　The ADS5294 has a digital processing block that integrates several commonly used digital functions for improving system performance. It includes a digital filter module that has built-in decimation filters (with low-pass, high-pass and band-pass characteristics).

　　The decimation rate is also programmable (by 2, by , or by 8). This makes it useful for narrow-band applications, where the filters can be used conveniently to improve SNR and knock-off harmonics, while at the same time reducing the output data rate. The device includes an averaging mode where two channels (or even four channels) can be averaged to improve SNR.

　　Serial LVDS outputs reduce the number of interface lines and enable the highest system integration. The digital data from each channel ADC can be output over one or two wires of LVDS output lines depending on the ADC sampling rate. This 2-wire interface helps keep the serial data rate low, allowing low cost FPGA based receivers to be used even at high sample rate. The ADC resolution can be programmed to 12 bit or 14 bit through register. A very unique feature is the programmable mapping module that allows flexible mapping between the input channels and the LVDS output pins. This helps greatly reduce the complexity of LVDS output routing and can potentially result in cheaper system boards by reducing the number of PCB layers.

　　The device integrates an internal reference trimmed to accurately match across devices. Best performance is expected to be achieved through the internal reference mode. The device can be driven with external references as well. The device is available in a 12 mm × 12 mm 80-pin QFP. It is specified over a –40°C to 85°C operating temperature range. ADS5294 is completely pin-to-pin and register compatible to ADS5292 QFP. It is specified over a –40°C to 85°C operating temperature range. ADS5294 is completely pin-to-pin and register compatible to ADS5292.

　　ADS5294主要特性:

　　Maximum Sample Rate: 80 MSPS/14-Bit

　　High Signal-to-Noise Ratio

　　75.5-dBFS SNR at 5 MHz/80 MSPS

　　78.2-dBFS SNR at 5 MHz/80 MSPS and Decimation Filter Enabled

　　84-dBc SFDR at 5 MHz/80 MSPS

　　Low Power Consumption

　　58 mW/CH at 50 MSPS

　　77 mW/CH at 80 MSPS (2 LVDS Wire Per Channel)

　　Digital Processing Block

　　Programmable FIR Decimation Filter and Oversampling to

　　Minimize Harmonic Interference

　　Programmable IIR High Pass Filter to Minimize DC Offset

　　Programmable Digital Gain: 0 dB to 12 dB

　　2- or 4- Channel Averaging

　　Flexible Serialized LVDS Outputs:

　　One or Two Wires of LVDS Output Lines per Channel

　　Depending on ADC Sampling Rate

　　Programmable Mapping Between ADC Input Channels and

　　LVDS Output Pins-Eases Board Design

　　Variety of Test Patterns to Verify Data Capture

　　by FPGA/Receiver

　　Internal and External References

　　1.8V Operation for Low Power Consumption

　　Low-Frequency Noise Suppression

　　ADS5294应用:

　　Ultrasound Imaging

　　Communication Applications

　　Multi-channel Data Acquisition

　　图1. ADS5294方框图

　　图2. ADS5294模拟输入模型

　　图3. ADS5294模拟输入驱动电路

　　ADS5294评估模块

　　This user’s guide gives a general overview of the evaluation module (EVM) and provides a general description of the features and functions to be considered while using this module. This manual is applicable to the ADS5294 analog-to-digital converters (ADC), which collectively are referred to as ADS529x. Use this document in combination with the respective ADC data sheet. The ADS529xEVM provides a platform for evaluating the ADC under various signal, clock, reference, and power supply conditions.

　　图4.ADS5294 EVM和TSW1250EVM硬件连接图

　　图5.ADS5294评估测试图

　　图6.ADS5294 EVM电路图(1)

　　图7.ADS5294 EVM电路图(2)

　　图8.ADS5294 EVM电路图(3)

　　图9.ADS5294 EVM电路图(4)

　　图10.ADS5294 EVM电路图(5)

　　图11.ADS5294 EVM电路图(6)

　　图12.ADS5294 EVM电路图(7)

　　图13.ADS5294 EVM电路图(8)

　　图14.ADS5294 EVM电路图(9)

　　ADS5294 EVM材料清单(BOM):

　　图15.ADS5294 EVM PCB布局图

　　详情请见:

　　http://www.ti.com/lit/ds/symlink/ads5294.pdf

　　和

　　http://www.ti.com/lit/ug/slau355/slau355.pdf