TI ADS1248 24位精密ADC传感器应用评估方案
TI 公司的ADS1246, ADS1247和ADS1248是高度集成的24位精密ADC,集成了低噪音可编程增益放大器(PGA),带单周期设定数字滤波器的精密Delta-Sigma ADC以及振荡器,组成了完整的温度/桥式传感器应用包括热耦合,电热调节器,RTD和应力测量的前端解决方案.本文介绍了ADS1246, ADS1247和ADS1248主要特性,以及ADS1248EVM评估板的主要特性,详细电路图和材料清单(BOM).The ADS1246, ADS1247, and ADS1248 are highly-integrated, precision, 24-bit analog-to-digital converters (ADCs). The ADS1246/7/8 feature an onboard, low-noise, programmable gain amplifier (PGA), a precision delta-sigma ADC with a single-cycle settling digital filter, and an internal oscillator. The ADS1247 and ADS1248 also provide a built-in, very low drift voltage reference with 10mA output capacity, and two matched programmable current digital-to-analog converters (DACs). The ADS1246/7/8 provide a complete front-end solution for temperature/bridge sensor applications including thermal couples, thermistors, RTDs, and strain-gauge applications.
An input multiplexer supports four differential inputs for the ADS1248, two for the ADS1247, and one for the ADS1246. In addition, the multiplexer has a sensor burnout detect, voltage bias for thermocouples, system monitoring, and general-purpose digital I/Os (ADS1247 and ADS1248). The onboard, low-noise PGA provides selectable gains of 1 to 128. The delta-sigma modulator and programmable digital filter settle in only one cycle, for fast channel cycling when using the input multiplexer, and support data rates up to 2kSPS. For data rates of 20SPS or less, both 50Hz and 60Hz interference are rejected by the filter.
The ADS1246 is offered in a small TSSOP-16 package, the ADS1247 is available in a TSSOP-20 package, and the ADS1248 in a TSSOP-28 package. All three devices are specified over the extended temperature range of –40℃ to +105℃.
ADS1248主要特性:
24 Bits, No Missing Codes
Data Output Rates Up to 2kSPS
Single-Cycle Settling for All Data Rates
Simultaneous 50/60Hz Rejection at 20SPS
4 Differential/7 Single-Ended Inputs (ADS1248)
2 Differential/3 Single-Ended Inputs (ADS1247)
Low-Noise PGA: 48nV at PGA = 128
Matched Current Source DACs
Very Low Drift Internal Voltage Reference: 10ppm/℃ (max)
Sensor Burnout Detection
4/8 General-Purpose I/Os (ADS1247/48)
Internal Temperature Sensor
Power Supply and VREF Monitoring
Self and System Calibration
SPI-Compatible Serial Interface
Unipolar (+3.3V to +5V)/Bipolar (±2.5V) Operation
Digital Supply: +3.3V or +5V
Operating Temperature –40℃ to +125℃
ADS1248应用:
Temperature Measurement
RTDs, Thermocouples, and Thermistors
Pressure Measurement
Industrial Process Control
图1.ADS1247/8方框图
图2.硬件补偿的三线RTD应用框图
ADS1248EVM评估板
ADS1148EVM, ADS1248EVM, ADS1148EVM-PDK, and ADS1248EVM-PDK
This users guide describes the characteristics, operation, and use of the ADS1148EVM and ADS1248EVM, both by themselves and as part of the ADS1148EVM-PDK or DS1248EVM-PDK. These evaluation modules (EVMs) are evaluation boards for the ADS1248, a 24-bit, multi-channel, delta-sigma analog-to-digital converter (ADC), and the ADS1148, a 16-bit version of the ADS1248. This EVM allows evaluation of all aspects of the ADS1148 or ADS1248 devices. Complete circuit descriptions, schematic diagrams, and bills of material are included in this document.
For use with a computer, the ADS1148EVM-PDK or ADS1248EVM-PDK is available. This kit combines the ADS1148/ADS1248EVM board with the MSP430-based MMB3 motherboard, and includes ADCPro software for evaluation.
The MMB3 motherboard allows the ADS1148/ADS1248EVM to be connected to the computer via an available USB port. This manual shows how to use the MMB3 as part of the
ADS1148EVM-PDK/ADS1248EVM-PDK, but does not provide technical details about the MMB3 itself.
图3. ADS1248EVM (左)和ADS1248EVM-PDK (右)外形图
The ADS1248EVM is an evaluation module built to the TI Modular EVM System specification. It can be connected to any modular EVM system interface card.
The ADS1248EVM is available as a stand-alone printed circuit board (PCB) or as part of the ADS1248EVM-PDK, which includes an MMB3 motherboard and software. As a stand-alone PCB, the ADS1248EVM is useful for prototyping designs and firmware.
Note that the ADS1248EVM has no microprocessor and cannot run software. To connect it to a computer, some type of interface is required.
ADS1148EVM/ADS1248EVM 主要特性:
Contains all support circuitry needed for the ADS1148/ADS1248
2.5V and +5V power-supply options for ADC
Voltage reference options: external or onboard
GPIO access
Compatible with the TI Modular EVM System
ADS1148EVM-PDK/ADS1248EVM-PDK 主要特性:
Easy-to-use evaluation software for Microsoft Windows XP
Data collection to text files
Built-in analysis tools including scope, FFT, and histogram displays
Complete control of board settings
Easily expandable with new analysis plug-in tools from Texas Instruments
图4.ADS1148EVM和 ADS1248EVM电路图
ADS1148EVM/ADS1248EVM 材料清单:
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