摘要：  TI公司的INA333是微功耗零漂移轨到轨精密仪表放大器，采用单一外接电阻可把增益设定在1到1000之间.工作电压低到1.8V(±0.9V)，静态电流仅为50uA，有极低的噪音密度(50nV/ Hz) .

关键字：  仪表放大器，  压力传感器，  ECG心电图

TI公司的INA333是微功耗零漂移轨到轨精密仪表放大器，采用单一外接电阻可把增益设定在1到1000之间.工作电压低到1.8V(±0.9V)，静态电流仅为50uA，有极低的噪音密度(50nV/ Hz) .

广泛用于桥式放大器，心电图(ECG)放大器，压力传感器，医疗仪器和手提仪表，热电偶放大器和数据采集.本文介绍了INA333的主要性能， 方框图， 基本的连接电路，以及ECG心电图系统方框图，非常低功耗的ECG应用电路和血糖仪应用电路以及数据采集系统电路图.

INA333 Micro-Power (50uA)， Zerø-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 (25µV， G ≥ 100)， excellent offset voltage drift (0.1µV/°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 50µA—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: 25µV (max)， G=100

LOW DRIFT: 0.1µV/°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: 50µA

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

RFI FILTERED INPUTS

MSOP-8 AND DFN-8 PACKAGES

应用:

BRIDGE AMPLIFIERS

ECG AMPLIFIERS

PRESSURE SENSORS

MEDICAL INSTRUMENTATION

PORTABLE INSTRUMENTATION

WEIGH SCALES

THERMOCOUPLE AMPLIFIERS

RTD SENSOR AMPLIFIERS

DATA ACQUISITION

图5.单电源非常低功耗的ECG应用电路

图6.用于以电池为能源的手持设备的低功耗对数功能的应用电路(血糖仪案例)

图7.用于PT100 RTD的四线3V调理电路(带可编程增益采集系统)