Datasheet AD8237 (Analog Devices) - 26
| Manufacturer | Analog Devices |
| Description | Micropower, Zero Drift, True Rail-to-Rail Instrumentation Amplifier |
| Pages / Page | 28 / 26 — AD8237. Data Sheet. IN AN ECG FRONT END. INSTRUMENTATION. AMPLIFIER. … |
| File Format / Size | PDF / 657 Kb |
| Document Language | English |
AD8237. Data Sheet. IN AN ECG FRONT END. INSTRUMENTATION. AMPLIFIER. PATIENT. G = +100. +5V. PROTECTION. 110kΩ. ECG OUT. 100kΩ. 47nF. 22nF. REF. 1kΩ
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AD8237 Data Sheet AD8237 IN AN ECG FRONT END
With this system architecture, large gains can be applied at the in-amp Electrocardiogram (ECG) circuits must operate with a differential stage, and the requirements of the rest of the system can be greatly dc offset due to the half-cell potential of the electrodes. The tolerance reduced. This also reduces noise and offset error contributions from for this over potential is typically ±300 mV; however, it can be a volt devices after the in-amp in the signal path. The circuit in Figure 77 or more in some situations. As ECG circuits move to lower supply illustrates the core concept. Additional op amps can be added for voltages, the half-cell potential problem becomes more difficult, improved performance, such as input buffering, filtering, and driven strictly limiting the gain that can be applied in the first stage. The lead, if it is required by the system. Proper decoupling is not shown. AD8237 architecture provides a unique solution to this problem. If the REF pin is left unconnected to the gain setting network, a low frequency inverting integrator can be connected from the output to the REF pin. Because the AD8237 applies gain to the integrator output, the integrator only has to swing as far as the dc offset to compensate for it, rather than the dc offset multiplied by the gain.
INSTRUMENTATION AMPLIFIER PATIENT G = +100 +5V PROTECTION A B 110kΩ AD8237 ECG OUT FB 100kΩ 47nF 22nF REF 1kΩ +5V VMID C 3.3μF 100kΩ +5V +5V VMID 100kΩ 2MΩ AD8607 AD8607
079 10289- Figure 77. AD8237 in ECG Rev. 0 | Page 26 of 28 Document Outline Features Applications General Description Pin Configuration Table of Contents Revision History Specifications Absolute Maximum Ratings Thermal Resistance ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Architecture Setting the Gain Gain Accuracy Clock Feedthrough Input Voltage Range Input Protection Filtering Radio Frequency Interference Using the Reference Pin Layout Common-Mode Rejection Ratio over Frequency Power Supplies Reference Input Bias Current Return Path Applications Information Battery Current Monitor Programmable Gain In-Amp AD8237 in an ECG Front End Outline Dimensions Ordering Guide
AD8237 Data Sheet AD8237 IN AN ECG FRONT END
With this system architecture, large gains can be applied at the in-amp Electrocardiogram (ECG) circuits must operate with a differential stage, and the requirements of the rest of the system can be greatly dc offset due to the half-cell potential of the electrodes. The tolerance reduced. This also reduces noise and offset error contributions from for this over potential is typically ±300 mV; however, it can be a volt devices after the in-amp in the signal path. The circuit in Figure 77 or more in some situations. As ECG circuits move to lower supply illustrates the core concept. Additional op amps can be added for voltages, the half-cell potential problem becomes more difficult, improved performance, such as input buffering, filtering, and driven strictly limiting the gain that can be applied in the first stage. The lead, if it is required by the system. Proper decoupling is not shown. AD8237 architecture provides a unique solution to this problem. If the REF pin is left unconnected to the gain setting network, a low frequency inverting integrator can be connected from the output to the REF pin. Because the AD8237 applies gain to the integrator output, the integrator only has to swing as far as the dc offset to compensate for it, rather than the dc offset multiplied by the gain.
INSTRUMENTATION AMPLIFIER PATIENT G = +100 +5V PROTECTION A B 110kΩ AD8237 ECG OUT FB 100kΩ 47nF 22nF REF 1kΩ +5V VMID C 3.3μF 100kΩ +5V +5V VMID 100kΩ 2MΩ AD8607 AD8607
079 10289- Figure 77. AD8237 in ECG Rev. 0 | Page 26 of 28 Document Outline Features Applications General Description Pin Configuration Table of Contents Revision History Specifications Absolute Maximum Ratings Thermal Resistance ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Architecture Setting the Gain Gain Accuracy Clock Feedthrough Input Voltage Range Input Protection Filtering Radio Frequency Interference Using the Reference Pin Layout Common-Mode Rejection Ratio over Frequency Power Supplies Reference Input Bias Current Return Path Applications Information Battery Current Monitor Programmable Gain In-Amp AD8237 in an ECG Front End Outline Dimensions Ordering Guide