Analog Devices introduced a low-power, single-lead, heart-rate monitor analog front end for a wide range of vital sign monitoring applications. The AD8232 AFE was designed specifically to meet the ECG signal conditioning requirements of emerging fitness, portable/wearable monitoring and remote health monitoring equipment. Unlike the topologies employed in many of today’s integrated solutions, the highly flexible analog filtering configuration of the AD8232 incorporates a two-pole, high-pass filter that is tightly coupled with the IC’s instrumentation amplifier architecture, and an uncommitted operational (gain) amplifier that enables the user to employ multi-pole low pass filtering techniques to remove line noise and other interference.
By performing large-gain and high-pass signal conditioning in a single stage in the analog domain, the AD8232 can accommodate electrode DC offsets while operating on a single supply voltage without sacrificing performance or signal quality. With an analog output, the AD8232 can be paired with either a discrete A/D converter or a microcontroller with an embedded A/D converter, which provides system designers with the flexibility to deliver a new level of value and performance for fitness and healthcare monitoring.
In addition to the instrumentation and gain amplifier, the AD8232 heart-rate monitor AFE incorporates a reference buffer, right leg drive circuit and shutdown function. The AD8232 also includes user-selectable (AC or DC) leads-off detect circuitry that monitors when an electrode is disconnected from the patient or user, providing an alert to the system. This new heart-rate monitor AFE offers an innovative fast-restore mode that quickly and automatically recovers the cardiac signal in the event a user temporarily loses contact with an electrode during exercise, or other activity, greatly improving the quality of the end-user experience.
