●The AFE4400 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 AFE4400, 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 VQFN-40 package (6 mm × 6 mm) and is specified over the operating temperature range of 0°C to 70°C.
● Fully-Integrated Analog Front-End for Pulse Oximeter Applications:
● Flexible Pulse Sequencing and
●Timing Control
● Transmit:
● Integrated LED Driver
●(H-Bridge, Push, or Pull)
● Dynamic Range: 95 dB
● LED Current:
● Programmable to 50 mA with 8-Bit Current Resolution
● Low Power:
● 100 µA + Average LED Current
● Programmable LED On-Time
● Independent LED2 and LED1 Current Reference
● Receive Channel with High Dynamic Range:
● 13 Noise-Free Bits
● Low Power: < 670 µA at 3.3-V Supply
● Integrated Digital Ambient Estimation and Subtraction
● Flexible Receive Sample Time
● Flexible Transimpedance Amplifier with Programmable LED Settings
● Integrated Fault Diagnostics:
● Photodiode and LED Open and
●Short Detection
● Cable On and Off Detection
● Supplies:
● Rx = 2.0 V to 3.6 V
● Tx = 3.0 V to 5.25 V
● Package: Compact VQFN-40 (6 mm × 6 mm)
● Specified Temperature Range: 0°C to 70°C
