24-Bit, 4.7 Hz, 4-Channel Analog Data Acquisiton System (CN0251)

The circuit shown in Figure 1 is a flexible signal conditioning circuit for processing signals of wide dynamic range, varying from several mV p-p to 20 V p-p. The circuit provides the necessary conditioning and level shifting and achieves the dynamic range using the internal programmable gain amplifier (PGA) of the high resolution analog-to-digital converter (ADC).


A ±10 V full-scale signal is very typical in process control and industrial automation applications; however, in some situations, the signal can be as small as several mV. Attenuation and level shifting is necessary to process a ±10 V signal with modern low voltage ADCs. However, amplification is needed for small signals to make use of the dynamic range of the ADC. Therefore, a circuit with a programmable gain function is desirable when the input signal varies over a wide range.


In addition, small signals may have large common-mode voltage swings; therefore, high common-mode rejection (CMR) is required. In some applications, where the source impedance is large, high impedance is also necessary for the analog front-end input circuit.



Figure 1. Flexible Analog Front-End Circuit for Wide Industrial Range Signal Conditioning

The circuit shown in Figure 1 solves all of these challenges and provides programmable gain, high CMR, and high input impedance. The input signal passes through the 4-channel ADG1409 multiplexer into the AD8226 low cost, wide input range instrumentation amplifier. The AD8226 offers high CMR up to 80 dB and very high input impedance (800 MΩ differential mode and 400 MΩ common mode). A wide input range and rail-to-rail output allow the AD8226 to make full use of the supply rails.


The AD8475 is a fully differential, attenuating amplifier with integrated precision gain resistors. It provides precision attenuation (G = 0.4 or G = 0.8), common-mode level shifting, and single-ended-to-differential conversion. The AD8475 is an easy to use, fully integrated precision gain block, designed to process signal levels up to ±10 V on a single supply. Therefore, the AD8475 is suitable for attenuating signals from the AD8226 up to 20 V p-p, while maintaining high CMR and offering a differential output to drive the differential input ADC.


The AD7192 is a 24-bit sigma-delta (Σ-Δ) ADC with an internal PGA. The on-chip, low noise gain stage (G = 1, 8, 16, 32, 64, or 128) means that signals of large and small amplitude can be interfaced directly to the ADC.


With the combination of the previous parts, the circuit offers very good performance and easy configuration for signals with varying amplitudes. The circuit can be used in industrial automation, process control, instrumentation, and medical equipment applications.



Возможности

  • 4-channel wide dynamic range
  • Industrial signal levels
  • In-amp input stage for high CMR

Файлы

Схемы и диаграммы

Быстро получите общее представление о схемотехнике решения

24-Bit, 4.7 Hz, 4-Channel Analog Data Acquisiton System  CN0251

Используемые компоненты

Производитель: Analog Devices Inc.
Наименование
Производитель
Описание Корпус/
Изображение
Цена, руб. Наличие
ADG1409YRUZ
ADG1409YRUZ
Analog Devices Inc.
Арт.: 292552 PDF RD
Доступно: 5346 шт. от: 383 руб.
IC, MUX, 4-CH, SMD, TSSOP16, 1409
ADG1409YRUZ 383,00 от 10 шт. 328,00 от 21 шт. 301,00
290 шт.
(на складе)
5056 шт.
(под заказ)
ADG1409YCPZ-REEL7
ADG1409YCPZ-REEL7
Analog Devices Inc.
Арт.: 1068611 PDF RD
Доступно: 30364 шт.
Выбрать
условия
поставки
ANALOGUE MULTIPLEXER, 4 TO 1, LFCSP-16
ADG1409YCPZ-REEL7
30364 шт.
(под заказ)
Выбрать
условия
поставки
ADG1409YRUZ-REEL7
Analog Devices Inc.
Арт.: 2177734 RD
Доступно: 5265 шт.
Выбрать
условия
поставки
ADG1409YRUZ-REEL7
5265 шт.
(под заказ)
Выбрать
условия
поставки
ADG1409YRUZ-REEL
Analog Devices Inc.
Арт.: 2177798 RD
Поиск
предложений
ADG1409YRUZ-REEL
-
Поиск
предложений
ADG1409SRU-EP-RL7
Analog Devices Inc.
Арт.: 2389758 RD
Поиск
предложений
ADG1409SRU-EP-RL7
-
Поиск
предложений