Product Description
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AD8232 Sensor Module Single-Lead Heart Rate Monitoring Front-End The AD8232 is an integrated front-end suitable for signal conditioning cardiac biopotential signals for cardiac monitoring. This integrated signal conditioning module is designed for ECG and other biopotential measurement applications. This device is designed to extract, amplify, and filter weak biopotential signals in the presence of noise generated by motion or remote electrode placement. This design enables an ultra-low-power analog-to-digital converter (ADC) or embedded microcontroller to easily acquire the output signal. The AD8232 uses a two-pole high-pass filter to eliminate motion artifacts and electrode half-cell potential. This filter is tightly coupled with the instrumentation amplifier structure, enabling single-stage high gain and high-pass filtering, saving space and cost. The AD8232 uses a free-standing operational amplifier to create a three-pole low-pass filter, eliminating additional noise. The user can select the cutoff frequencies of all filters to meet the needs of different applications. To improve common-mode rejection of system line frequencies and other undesirable interference, the AD8232 includes an integrated amplifier for driven lead applications, such as right-side-driven (RLD). The AD8232 includes a fast recovery feature that reduces the otherwise long settling tail of the high-pass filter. If a sudden signal change in the amplifier rail voltage occurs (such as a leads-off condition), the AD8232 automatically adjusts to a higher filter cutoff. This feature allows the AD8232 to recover quickly, enabling valid measurements to be obtained soon after the leads are connected to the subject's electrodes. Performance is guaranteed over the 0°C to 70°C temperature range and operates over the -40°C to +85°C temperature range. |
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Applications Fitness and Sports Heart Rate Monitoring Portable ECG Remote Health Monitoring Gaming Peripherals Biological Signal Acquisition Pin Number Pin Name Description 1 HPDRIVE High-pass Driver Output. HPDRIVE should be connected to the capacitor in the first high-pass filter. The AD8232 drives this pin to maintain HPSENSE at the same voltage level as the reference voltage. 2 +IN Instrumentation Amplifier Positive Input. +IN is typically connected to the left arm (LA) electrode. 3 -IN Instrumentation Amplifier Negative Input. -IN is typically connected to the right arm (RA) electrode. 4 RLDFB Right Leg Drive Feedback Input. RLDFB is the feedback pin for the right leg drive circuit. 5 RLD Right Leg Drive Output. The drive electrode (typically the right leg) should be connected to the RLD pin. 6 SW Fast Recovery Switch Pin. This pin should be connected to the output of the second high-pass filter. 7 OPAMP+ Operational Amplifier Noninverting Input. 8 REFOUT Reference Buffer Output. The instrumentation amplifier output is referenced to this potential. REFOUT should be used as a virtual ground at any point in the circuit requiring a reference signal. 9 OPAMP- Operational amplifier inverting input. 10 OUT Operational amplifier output. This output provides a fully conditioned heart rate signal. OUT can be connected to the input of an ADC. 11 LOD- Lead-off comparator output. In DC lead-off detection mode, LOD- is high when the -IN electrode is disconnected, and low otherwise. In AC lead-off detection mode, LOD- is always low. Lead-off comparator output. In DC lead-off detection mode, LOD+ is high when the +IN electrode is disconnected, and low otherwise. In AC lead-off detection mode, LOD+ is high when either the -IN or +IN electrode is disconnected, and low when both electrodes are connected. 12 LOD+ 13 SDN Shutdown Control Input. Drive SDN low to enter low-power shutdown mode. 14 AC/DC Lead-Off Mode Control Input. For DC lead-off mode, drive the AC/DC pin low. For AC lead-off mode, drive the AC/DC pin high. 15 FR Fast Recovery Control Input. Drive FR high to enable fast recovery mode; otherwise, drive it low. 16 GND Power Ground. 17 +VS Power Supply Pin. 18 REFIN Reference Voltage Buffer Input. REFIN (high-impedance input pin) can be used to set the voltage level of the reference buffer. 19 IAOUT Instrumentation Amplifier Output Pin. 20 HPSENSE High-Pass Sense Input of the Instrumentation Amplifier. Connect HPSENSE to the junction of R and C, which sets the corner frequency of the DC blocking circuit. EP Exposed Pad. The exposed pad should be connected to GND or left unconnected. |
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