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[原创]ADI AD4134 24位4路同步采样1.5 MSPS模数转换器(ADC)解决方案

ADI公司的AD4134 是24位4路低噪音同步采样精密模数转换器(ADC),提高警惕供功能性,高性能和容易使用.基于连续时间sigma-delta (CTSD)调制方案, AD4134移除了传统所需要的开关电容电路取样程序Σ-Δ调制器,导致放宽了ADC输入驱动要求.CTSD架构还在ADC混淆频段周围固有抑制信号,使器件具有固有的抗混淆功能,从而不需要复杂的外部的抗混淆滤波器. AD4134具有极好的DC和AC性能,每路ADC的带宽从DC到391.5kHz,使得器件非常适合用在通用精密数据采集解决方案,支持各种类性传感器,从温度和压力到振动与震动.器件具有108dB动态范围(ODR = 374 kSPS, FIR滤波器),137dB动态范围(ODR = 10 SPS, sinc3滤波器),1kHz输入音调的THD为−120 dB,失调误差飘移为0.9 μV/°C,增益飘移为2 ppm/°C,INL为FSR的±2 ppm,平均模式的动态范围增强为4:1和2:1.A加权动态范围为126dB.Sinc3滤波器具有50 Hz/60 Hz 抑制,串扰为130.7 dBFS,菊花链连接,工作电压为4.5 V到5.5 V 和1.65 V到1.95 V,外接基准源为4.096 V 或5 V, 1.8 V IOVDD电平.主要用在电测量和测试,音频测试,3相电源质量分析,声纳,闭环验证的控制和硬件,预测性维修的条件监视, 声学和材料科学研究和开发.本文介绍了AD4134主要特性,功能框图,典型连接框图, 典型应用框图以及评估板EVAL-AD4134FMCZ主要特性和电路图.

24-Bit, 4-Channel Simultaneous Sampling 1.5 MSPS Precision Alias Free ADC

The AD4134 is a quad channel, low noise, simultaneous sampling, precision analog-to-digital converter (ADC) that delivers on functionality, performance, and ease of use.

Based on the continuous time sigma-delta (CTSD) modulation scheme, the AD4134 removes the traditionally required switched capacitor circuitry sampling preceding the Σ-Δ modulator, which leads to a relaxation of the ADC input driving requirement. The CTSD architecture also inherently rejects signals around the ADC aliasing frequency band, giving the device its inherent antialiasing capability, and removes the need for a complex external antialiasing filter.

The AD4134 has four independent converter channels in parallel, each with a CTSD modulator and a digital decimation and filtering path. The AD4134 enables simultaneous sampling of four separate signal sources, each supporting a maximum input bandwidth of

391.5 kHz and achieving tight phase matching between these four signal measurements. The high level of channel integration, together with its simplified analog front-end requirement, enables the AD4134 to provide a high density multichannel data acquisition

solution in a small form factor.

The signal chain simplification property of the AD4134 also improves the system level performance through the reduction of noise, error, mismatch, and distortion that is normally introduced by the analog front-end circuitry.

The AD4134 offers excellent dc and ac performance. The bandwidth of each ADC channel ranges from dc to 391.5 kHz, making the device an ideal candidate for universal precision data acquisition solutions supporting a breadth of sensor types, from temperature and pressure to vibration and shock.

The AD4134 offers a large number of features and configuration options, giving the user the flexibility to achieve the optimal balance between bandwidth, noise, accuracy, and power for a given application.

An integrated asynchronous sample rate converter (ASRC) allows the AD4134 to precisely control the decimation ratio and, in turn, the output data rate (ODR) using interpolation and resampling techniques.

The AD4134 supports a wide range of ODR frequencies, from 0.01 kSPS to 1496 kSPS with less than 0.01 SPS adjustment resolution, allowing the user to granularly vary sampling speed to achieve coherent sampling. The ODR value can be controlled through the ODR_VAL_INT_x and ODR_VAL_FLT_x registers (Register 0x16 to Register 0x1C, ASRC master mode), or using an external clock source (ASRC slave mode). The ASRC slave mode operation enables synchronous sampling between multiple AD4134 devices to a single system clock. The ASRC simplifies the clock distribution requirement within a medium bandwidth data acquisition system because it no longer requires a high frequency, low jitter master clock from the digital back end to be routed to each ADC.

The ASRC acts as a digital filter and decimates the oversampled data from the Σ-Δ modulator to a lower rate to favor higher precision.

The ADC data is then further processed by one of the AD4134 user-selectable digital filter profiles to further reject the out of band signals and noises, and reduce the data rate to the final desired ODR value.

The AD4134 offers three main digital filter profile options: a wideband low ripple filter with a brick wall frequency profile and an ODR range from 2.5 kSPS to 374 kSPS that is suitable for frequency domain analysis, a fast responding sinc3 filter with an ODR range

from 0.01 kSPS to 1496 kSPS that is suitable for low latency time domain analysis and low frequency high dynamic range input types, and a balanced sinc6 filter with an ODR range from 2.5 kSPS to 1.496 MSPS, offering optimal noise performance and response

time.

The AD4134 is also capable of performing on-board averaging between two or four of its input channels. The result is a near 3 dB, if two channels are combined, or 6 dB, if all four channels are combined, improvement in dynamic range while maintaining the bandwidth.

The AD4134 supports two device configuration schemes: serial peripheral interface (SPI) and hardware pin configuration (pin control mode). The SPI control mode offers access to all the features and configuration options available on the AD4134. SPI control mode also enables access to the on-board diagnostic features designed to enable a robust system design. Pin control mode offers the benefit of simplifying the device configuration, enabling the device to operate autonomously after power-up operating in a standalone mode.

In addition to the optional SPI, the AD4134 has a flexible and independent data interface for transmitting the ADC output data.

The data interface can act as either a bus master or a slave with various clocking options to support multiple communication bus protocols. The data interface also supports daisy-chaining and an optional minimum input/output (I/O) mode designed to minimize the

number of digital isolator channels required in isolated applications.

The AD4134 has an operating ambient temperature range from −40°C to 105°C. The device is housed in an 8 mm × 8 mm, 56-lead lead frame chip scale package (LFCSP).

Note that throughout this data sheet, multifunction pins, such as FORMAT1/SCLK, are referred to either by the entire pin name or by a single function of the pin, for example, SCLK, when only that function is relevant.

AD4134主要特性:

► Alias free: inherent antialias rejection high performance mode 102.5 dB, typical

► Excellent ac and dc performance

► 108 dB dynamic range at ODR = 374 kSPS, FIR filter, typical

► 137 dB dynamic range at ODR = 10 SPS, sinc3 filter, typical

► THD: −120 dB typical with 1 kHz input tone

► Offset error drift: 0.9 μV/°C typical

► Gain drift: 2 ppm/°C typical

► INL: ±2 ppm of FSR typical

► Dynamic range enhancement: 4:1 and 2:1 averaging mode

► 126 dB, A weighted dynamic range

► Resistive ADC and reference input

► Easy to sync: asynchronous sample rate converter

► Multidevice synchronization with one signal line

► Programmable data rates from 0.01 kSPS to 1496 kSPS with resolution of 0.01 SPS

► Option to control output data rate by external signal

► Linear phase digital filter options

► Low ripple FIR filter: 32 μdB pass-band ripple, dc to 161.942 kHz

► Low latency sinc3 filter and sinc6 filter, dc to 391.5 kHz

► Sinc3 filter with 50 Hz/60 Hz rejection

► Crosstalk: 130.7 dBFS

► Daisy-chaining

► CRC error checking on data and SPI

► Two power modes: high performance mode and low power mode

► Power supply: 4.5 V to 5.5 V and 1.65 V to 1.95 V

► 1.8 V IOVDD level

► External reference: 4.096 V or 5 V

► Crystal or external CMOS clock of 48 MHz

► SPI or pin (standalone) configurable operation

► Operating temperature range: −40°C to +105°C

► Available in 8 mm × 8 mm, 56-lead LFCSP with exposed pad

AD4134应用:

► Electrical test and measurement

► Audio test

► 3-phase power quality analysis

► Control and hardware in loop verification

► Sonars

► Condition monitoring for predictive maintenance

► Acoustic and material science research and development

图1. AD4134功能框图(1)

图2. AD4134功能框图

图3. AD4134典型连接框图

图4. AD4134典型应用框图

评估板EVAL-AD4134FMCZ

The evaluation kit features the AD4134 24-bit, 4-channel, simultaneous sampling, 1.5 MSPS precision alias free analog-to-digital converter (ADC). The EVAL-AD4134FMCZ draws power from the system demonstration platform (SDP) EVAL-SDPCH1Z (SDP-H1) board, and the on-board dc-to-dc regulators regulate an external supply of 8 V to 14 V down to 5 V and 1.8 V to supply the AD4134 and peripheral components. A separate

reference of 4.096 V generated by the on‑board ADR444. The ADC is clocked by an on-board crystal.

The EVAL-AD4134FMCZ connects to the PC USB port via the SDP-H1 board.

The AD4134 evaluation software running on a PC provides full accessibility to the AD4134 device register map, as well as a data analysis interface to display key parameters and graphics from the conversion result in both time and frequency domains.

For full details on the AD4134, see the AD4134 data sheet, which must be consulted in conjunction with this user guide when using the EVAL-AD4134FMCZ.

评估板EVAL-AD4134FMCZ主要特性:

► Fully featured evaluation board for the AD4134

► PC control in conjunction with the SDP-H1 board

► PC software control and data analysis

► Standalone hardware capability

评估板EVAL-AD4134FMCZ 包括:

► EVAL-AD4134FMCZ board

► AD4134