Maxim already serves this market space with a number of products, primarily for the “fitness wearables” market domain. At present, a company spokesman said, that business is much greater than the corresponding delivery of product to the clinical part of the market. Now, however, Maxim sees a convergence between the two, with its “fitness” customers seeking to obtain approval (FDA in the USA) for products certified as having the performance to operate as clinical devices – yielding data that can be the basis of medical diagnosis and treatment. Examples quoted include product categories such as an ECG patch, in which the front-end signal capture and processing moves to the (potentially, consumable/disposable) skin patch; and continuous blood-glucose monitoring by non-invasive means.
The two device familes in this announcement comprise the MAX86140 and MAX86141 optical pulse oximeter/heart rate sensor ICs and the MAX30001 electrocardiogram (ECG) and bioimpedance (BioZ) analogue front end (AFE).
MAX30001 is a complete, biopotential and bioimpedance (BioZ), AFE for wearables. It has two channels; a bioimpedance (skin resistance) channel that has an excitation current source and voltage measurement connection; and an ECG input that measures the body’s own potentials. Specifications (product page here) include clinical-grade ECG data conversion of 15.9 bits ENOB with 3.1 µV PP (typ) noise for ECG; and 17 bits ENOB with 1.1 µV PP noise for BioZ applications. Power usage of 85 µW at 1.1V supply voltage (or 158 µW for BioZ operation) extends battery life in continuous monitoring. The MAX30001 is a single biopotential channel providing ECG waveforms, heart rate and pacemaker edge detection, plus a single bioimpedance channel capable of measuring respiration.
The biopotential and bioimpedance channels have ESD protection, EMI filtering, internal lead biasing, DC leads-off detection, ultra-low-power, leads-on detection during standby mode, and calibration voltages for built-in self-test. Soft power-up sequencing ensures no large transients are injected into the electrodes. Both channels also have high input