Ultra-Small Integrated Analog Front End (AFE) for Heart-Rate Monitors and Low-Cost Pulse Oximeters

The AFE4403 is a fully-integrated analog front-end

(AFE) ideally suited for pulse oximeter applications. The device consists of a

low-noise receiver channel with an integrated analog-to-digital converter (ADC), an

LED transmit section, and diagnostics for sensor and LED fault detection. The device

is a very configurable timing controller. This flexibility enables the user to have

complete control of the device timing characteristics. To ease clocking requirements

and provide a low-jitter clock to the AFE4403, an oscillator is also integrated that

functions from an external crystal. The device communicates to an external

microcontroller or host processor using an SPI™ interface.

The device is a complete AFE solution packaged in

a single, compact DSBGA-36 (3.07 mm × 3.07 mm × 0.5 mm) and is specified over the

operating temperature range of –20°C to 70°C.