说明：  AFE4400 是一款非常适合于脉冲血氧仪应用的完全集成模拟前端 (AFE)。 此器件包含一个具有集成模数转换器 (ADC) 的低噪声接收器通道、一个 LED 发射部件和针对传感器以及 LED 故障检测的诊断功能。 此器件是一款可配置定时控制器。 这个灵活性使得用户能够完全控制器件定时特性。 为了简化计时要求并为 AFE4400 提供一个低抖动时钟，还集成了一个由外部晶振供频的振荡器。 此器件使用一个 SPI 接口与外部微控制器或主机处理器通信。
(The AFE4400 is a fully-integrated analog front-end (AFE) ideally suited for pulse oximeter applications. (H-Bridge, Push, or Pull) The device consists of a low-noise receiver channel – Dynamic Range: 95 dB with an integrated analog-to-digital converter (ADC), – LED Current: an LED transmit section, and diagnostics for sensor – Programmable to 50 mA with 8-Bit Current and LED fault detection. The device is a very Resolution configurable timing controller. This flexibility enables the user to have complete control of the device timing – Low Power: characteristics. To ease clocking requirements and – 100 μA+ Average LED Current provide a low-jitter clock to the AFE4400, an oscillator – Programmable LED On-Time is also integrated that functions an external crystal. The device communicates to an external – Independent LED2 and LED1 Current microcontroller or host processor using an SPI™ Reference interface. )