Complete 5 V, Single-Supply, 8-Channel Multiplexed Data Acquisition System with PGIA for Industrial Signal Levels (CN0201)
The circuit shown in Figure 1 is a highly integrated 16-bit, 1 MSPS, multiplexed 8-channel flexible data acquisition system (DAS) with a programmable gain instrumentation amplifier (PGIA) capable of handling the full range of industrial signal levels.
Figure 1. Complete 5 V, Single-Supply, 8-Channel Data Acquisition Solution with Integrated PGIA (Simplified Schematic: All Connections and Decoupling Not Shown)
A single +5 V supply powers the circuit, and a high efficiency, low ripple boost converter generates the ±15 V that allows processing differential input signals up to ±24.576 V with ±2 LSB INL (maximum), and ±0.5 LSB DNL (typical). For high accuracy applications, this compact and cost-effective circuit offers high precision, as well as low noise.
The successive approximation register (SAR)-based data acquisition system includes true high impedance differential input buffers; therefore, there is no need for additional buffering, as is usually required to reduce kickback in capacitive digital-toanalog converter (DAC)-based SAR analog-to-digital converters (ADCs). In addition, the circuit has high common-mode rejection, eliminating the need for external instrumentation amplifiers, which are typically required in applications where common-mode signals are present.
The ADAS3022 is a complete 16-bit, 1 MSPS data acquisition system that integrates an 8-channel, low leakage multiplexer; a programmable gain instrumentation amplifier stage with a high common-mode rejection; a precision low drift 4.096 V reference; a reference buffer; and a high performance, no latency, 16-bit SAR ADC. The ADAS3022 reduces its power at the end of each conversion cycle; therefore, the operating currents and power scale linearly with throughput make it ideal for the low sampling rates in battery-powered applications.
The ADAS3022 has eight inputs and a COM input that can be configured as eight single-ended channels, eight channels with a common reference, four differential channels, or various combinations of single-ended and differential channels.
In the circuit shown in Figure 1, the reference is supplied by the ADR434 low noise reference buffered by an AD8031 op amp. The AD8031 is ideally suited as a reference buffer because of its ability to drive dynamic loads with fast recovery.
The ADP1613 is a dc-to-dc boost converter with an integrated power switch and provides the ADAS3022 high voltage ±15 V supplies required for the on-chip input multiplexer and the programmable gain instrumentation amplifier without compromising the performance of the ADAS3022.
This circuit offers high precision, as well as low noise, which is ensured by the combination of the ADAS3022, ADP1613, ADR434, and AD8031 precision components.
Схемы и диаграммы
Быстро получите общее представление о схемотехнике решения
Печатные платы и ПО
Ускорьте разработку по готовому дизайну