TI INA333 ECG心電圖應用方案

TI公司的INA333是微功耗零漂移軌到軌精密儀表放大器,采用單一外接電阻可把增益設定在1到1000之間.工作電壓低到1.8V(±0.9V),靜態電流僅為50uA,有極低的噪音密度(50nV/ Hz) .

廣泛用于橋式放大器,心電圖(ECG)放大器,壓力傳感器,醫療儀器和手提儀表,熱電偶放大器和數據采集.本文介紹了INA333的主要性能, 方框圖, 基本的連接電路,以及ECG心電圖系統方框圖,非常低功耗的ECG應用電路和血糖儀應用電路以及數據采集系統電路圖.

INA333 Micro-Power (50uA), Zeroslash;-Drift, Rail-to-Rail Out Instrumentation Amplifier

The INA333 is a low-power, precision instrumentation amplifier offering excellent accuracy. The versatile 3-op amp design, small size, and low power make it ideal for a wide range of portable applications.

A single external resistor sets any gain from 1 to 1000. The INA333 is designed to use an industry-standard gain equation: G = 1 + (100k /RG).

The INA333 provides very low offset voltage (25micro;V, G ≥ 100), excellent offset voltage drift (0.1micro;V/°C, G ≥ 100), and high common-mode rejection (100dB at G ≥ 100). It operates with power supplies as low as 1.8V (±0.9V), and quiescent current is only 50micro;A—ideal for battery-operated systems. Using autocalibration techniques to ensure excellent precision over the extended industrial temperature range, the INA333 also offers exceptionally low noise density (50nV/ Hz) that extends down to dc.

The INA333 is available in both MSOP-8 and DFN-8 surface-mount packages and is specified over the TA = -40°C to +125°C temperature range.

主要特性:

LOW OFFSET VOLTAGE: 25micro;V (max), G=100

LOW DRIFT: 0.1micro;V/°C, G=100

LOW NOISE: 50nV/ Hz, G=100

HIGH CMRR: 100dB (min), G=10

LOW INPUT BIAS CURRENT: 200pA (max)

SUPPLY RANGE: +1.8V to +5.5V

INPUT VOLTAGE: (V-) +0.1V to (V+) -0.1V

OUTPUT RANGE: (V-) +0.05V to (V+) -0.05V

LOW QUIESCENT CURRENT: 50micro;A

OPERATING TEMPERATURE: -40°C to +125°C

RFI FILTERED INPUTS

MSOP-8 AND DFN-8 PACKAGES

應用:

BRIDGE AMPLIFIERS

ECG AMPLIFIERS

PRESSURE SENSORS

MEDICAL INSTRUMENTATION

PORTABLE INSTRUMENTATION

WEIGH SCALES

THERMOCOUPLE AMPLIFIERS

RTD SENSOR AMPLIFIERS

DATA ACQUISITION

圖1. INA333方框圖

圖2. INA333基本連接電路

圖3.ECG心電圖系統方框圖

圖4.帶右腿驅動的ECG放大框圖

圖5.單電源非常低功耗的ECG應用電路

圖6.用于以電池為能源的手持設備的低功耗對數功能的應用電路(血糖儀案例)

圖7.用于PT100 RTD的四線3V調理電路(帶可編程增益采集系統)

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