TI公司的ADS1262是32位低噪音低漂移38.4-kSPS Delta-Sigma (ΔΣ) ADC,集成了PGA,基准电压和内部故障监视器,数据速率2.5 SPS 到38400 SPS,失调1 nV/℃,增益漂移 0.5 ppm/℃,线性度3ppm,噪音7 nV_RMS(2.5 SPS,增益= 32),主要用在高分辨率PLC,温度和压力测量仪,称重仪和应力表,分析仪器,图表记录仪和面板表.本文介绍了ADS1262主要特性,框图和应用电路,以及高分辨率低漂移称重仪参考设计TIPD188主要特性, ,材料清单和PCB布局图.

The ADS1262 and ADS1263 are low-noise, low-drift, 38.4-kSPS, delta-sigma (ΔΣ) ADCs with an integrated PGA, reference, and internal fault monitors. The ADS1263 integrates an auxiliary, 24-bit, ΔΣ ADC intended for background measurements. The sensor-ready ADCs provide complete, high-accuracy, one-chip measurement solutions for the most-demanding sensor applications, including weigh scales, strain-gauge sensors, thermocouples, and resistance temperature devices (RTD).

The ADCs are comprised of a low-noise, CMOS PGA (gains 1 to 32), a ΔΣ modulator, followed by a programmable digital filter. The flexible analog front-end (AFE) incorporates two sensor-excitation current sources suitable for direct RTD measurement.

A single-cycle settling digital filter maximizes multiple-input conversion throughput, while providing 130-dB rejection of 50-Hz and 60-Hz line cycle interference.

The ADS1262 and ADS1263 are pin and functional compatible. These devices are available in a 28-pin TSSOP package and are fully specified over the –40℃ to +125℃ temperature range.

ADS1262主要特性:

Precision, 32-bit, ΔΣ ADC
Auxiliary 24-Bit, ΔΣ ADC (ADS1263)
Data Rates: 2.5 SPS to 38400 SPS
Differential Input, CMOS PGA
11 Multifunction Analog Inputs
High-Accuracy Architecture
Offset Drift: 1 nV/℃
Gain Drift: 0.5 ppm/℃
Noise: 7 nV_RMS (2.5 SPS, Gain = 32)
Linearity: 3 ppm
2.5-V Internal Voltage Reference
Temperature Drift: 2 ppm/℃
50-Hz and 60-Hz Rejection
Single-Cycle Settled Conversions
Dual Sensor Excitation Current Sources
Internal Fault Monitors
Internal ADC Test Signal
8 General-Purpose Input/Outputs

ADS1262应用:

? High-Resolution PLCs
? Temperature, Pressure Measurement
? Weigh Scales and Strain-Gauge Digitizers
? Panel Meters, Chart Recorders
? Analytical Instrumentation

图1.ADS1262框图

图2.ADS1262温度补偿桥式测量

高分辨率低漂移称重仪参考设计TIPD188

High-Resolution, Low-Drift, Precision Weigh-Scale Reference Design with AC Bridge Excitation TIPD188

This precison weigh-scale reference design achieves greater than 50,000 noise-free counts of resolution. Offset and offset drift errors are nearly eliminated by ac bridge excitation. This design takes advantage of the high-resolution ADS1262 delta-sigma ADC.

称重仪参考设计TIPD188主要特性:

>50,000 noise-free count weigh-scale solution
Operating temperature range: -40 ℃ to +125 ℃
Less than 1 μV total error across temperature range
ADC Supply and Bridge Excitation Voltage: 5V
Bridge Output: 0 V to 10 mV
Firmware provides ADS1262 example code
This robust circuit reference design includes theory, complete error analysis, component selection, simulation, PCB design, example code, and measured data that correlates with the theory and simulation

图3.称重仪参考设计TIPD188外形图

图4.称重仪参考设计TIPD188框图

图5.称重仪参考设计TIPD188 (1)

图6.称重仪参考设计TIPD188 (2)
称重仪参考设计TIPD188材料清单:



图7.称重仪参考设计TIPD188 PCB布局图
详情请见:
http://www.ti.com/lit/ds/symlink/ads1262.pdf
和http://www.ti.com/lit/ug/tiduac1/tiduac1.pdf
以及http://www.ti.com/lit/df/tidrg59/tidrg59.pdf

ads1262.pdf
tiduac1.pdf
tidrg59.pdf