The AD8233 is an integrated signal conditioning block for ECG and other biopotential measurement applications. It is designed to extract, amplify, and filter small biopotential signals in the presence of noisy conditions, such as those created by motion or remote electrode placement. This design allows an ultralow power analog-to-digital converter (ADC) or an embedded microcontroller to easily acquire the output signal.
The AD8233 implements a two-pole high-pass filter for eliminating motion artifacts and the electrode half cell potential. This filter is tightly coupled with the instrumentation architecture of the amplifier to allow both large gain and high-pass filtering in a single stage, thereby saving space and cost.
An uncommitted operational amplifier enables the AD8233 to create a three-pole, low-pass filter to remove additional noise. The user can select the frequency cutoff of all filters to suit different types of applications.
To improve the common-mode rejection of the line frequencies in the system and other undesired interferences, the AD8233 includes an amplifier for driven lead applications, RLD.
The AD8233 includes a fast restore function that reduces the duration of the otherwise long settling tails of the high-pass filters. After an abrupt signal change that rails the amplifier (such as a leads off condition), the AD8233 automatically adjusts to a higher filter cutoff. This feature allows the AD8233 to recover quickly, and therefore, to take valid measurements soon after connecting the electrodes to the subject.
The AD8233 is available in a 2 mm × 1.7 mm, 20-ball WLCSP package. Performance is specified from 0°C to 70°C and is operational from −40°C to +85°C.
- Fitness and activity heart rate monitors
- Portable ECG
- Wearable and remote health monitors
- Gaming peripherals
- Biopotential signal acquisition, such as EMG
The ADAS1000 measures electro cardiac (ECG) signals, thoracic impedance, pacing artifacts, lead on/off status and outputs this information in the form of a data frame supplying either Lead/Vector or Electrode data at programmable data rates. Its low power and small size make it suitable for portable, battery powered applications. The high performance also makes it suitable for higher end diagnostic machines.
The ADAS1000 is designed to simplify the task of acquiring and ensuring quality ECG signals. Value-added cardiac postprocessing is executed externally on a DSP, microprocessor or FPGA. Several digital output options ensure flexibility when monitoring and analyzing signals. The ADAS100
0 provides a low power, small data acquisition system for biopotential applications.
Auxiliary features that aid in better quality ECG signal acquisition include: multi-channel averaged driven lead, selectable reference drive, fast over load recovery, flexible respiration circuitry returning magnitude and phase information, internal pace detection algorithm operating on 3 leads and option of AC or DC leads off detection.
Since ECG systems span different applications, the ADAS1000 features a flexible power/noise scaling architecture where the noise can be reduced at the expense of increasing power consumption. Signal acquisition channels may be shutdown to save power. Data rates can be reduced to save power.
To ease manufacturing tests, development, as well as offer holistic power-up testing, the ADAS1000 offers a suite of dc and ac test excitation via the CAL DAC, CRC redundancy testing in addition to read-back of all relevant register address space.
The ADAS1000 is available in two package options, either a 56 lead LFCSP or a 64 lead LQFP package and is specified over -40°C to +85°C temperature range. The ADAS1000 is a full featured 5 channel ECG including respiration and pace detection, while the ADAS1000-1 offers only ECG channels with no respiration or pace features. Similarly the ADAS1000-2 is a subset of the main device and is configured for gang purposes with only ECG channels enabled (no respiration, pace, RLD, etc).
APPLICATIONSECG: Monitor & Diagnostic
- Bedside Patient Monitoring
- Portable Telemetry
- Cardiac Defibrillators
- Ambulatory Monitors
- Pace Maker Programmer
- Patient Transport
- Stress testing
The AD8237 is a micropower, zero drift, rail-to-rail input and output instrumentation amplifier. The relative match of two resistors sets any gain from 1 to 1000. The AD8237 has excellent gain accuracy performance that can be preserved at any gain with two ratio-matched resistors.
The AD8237 employs the indirect current feedback architecture to achieve a true rail-to-rail capability. Unlike conventional in-amps, the AD8237 can fully amplify signals with common-mode voltage at or even slightly beyond its supplies. This enables applications with high common-mode voltages to use smaller supplies and save power.
The AD8237 is an excellent choice for portable systems. With a minimum supply voltage of 1.8 V, a 115 μA typical supply current, and wide input range, the AD8237 makes full use of a limited power budget, yet offers bandwidth and drift performance suitable for bench-top systems.
- Bridge amplification
- Pressure measurement
- Medical instrumentation
- Thermocouple interface
- Portable systems
- Current measurement
- Building Control and Automation
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