AFE4432
- Supports signal acquisition of up to 12 phase sets
- Supports up to 4 LEDs, 3 PDs
- Flexible allocation of LEDs, PDs in each phase
- Simultaneous signal acquisition from different sensors at different data rates
- Accurate, continuous PPG monitoring:
- Low current for continuous heart-rate monitoring on a wearable device with a typical value: 12 µA for the receiver
- Peak system SNR of 115 dB in 0.5-10 Hz band enables high-accuracy SpO2 measurement
- Transmitter:
- 8-Bit Programmable LED current with range adjustable from 25 mA to 250 mA
- Mode to fire two LEDs in parallel with independent per-phase current control
- Programmable LED on-time per-phase
- Simultaneous support of 4 LEDs for SpO2, Multi-Wavelength HRM
- Receiver:
- Supports 3 Time-Multiplexed PD Inputs
- 2 parallel receivers (2 sets of TIA/filter)
- Individual ambient offset subtraction DAC at each TIA Input with 8-bit per-phase control and range adjustable up to 255-µA
- Individual LED offset subtraction DAC at each TIA input with 9-bit per-phase control and 64-µA range
- Digital ambient subtraction at ADC output
- Noise filtering with programmable bandwidth
- Transimpedance gain: 3.7 kΩ to 1 MΩ
- Supports external clock or internal oscillator
- Option to acquire data synchronized with a system clock
- Automatic cancellation of DC from Ambient, LED
- FIFO with 160-sample depth
- SPI™ interface/ I2C interface
- 1.9-mm × 1.8-mm DSBGA, 0.35-mm Pitch
- Supplies: Rx:1.7 - 1.9 V, Tx: 3-5.5 V
The AFE4432 is an analog front-end for optical bio-sensing applications, such as heart-rate monitoring (HRM) and saturation of peripheral capillary oxygen (SpO2). The device supports up to 4 switching light-emitting diodes (LEDs) and up to three photodiodes (PDs). The AFE has two LED drivers each with 8-bit current control. The device has a high dynamic range transmit-and-receive circuitry that helps with the sensing of very small signal levels. Up to 12 signal phase sets can be defined, each phase set comprising a combination of LED and Ambient phases. Low noise offset DACs at the receiver inputs can be automatically controlled to cancel DC from Ambient and LED light. The current from the PDs in each phase is converted into voltage by TIAs, filtered, and then digitized using a common ADC. The ADC code can be stored in a 160-sample FIFO block. The FIFO can be read out using a SPI or I2C interface.
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技術文件
| 重要文件 | 類型 | 標題 | 格式選項 | 下載最新的英文版本 | 日期 | |
|---|---|---|---|---|---|---|
| * | 資料表 | AFE4432 Ultra-Small, Integrated AFE for Optical Bio-Sensing datasheet | PDF | HTML | 2022/8/23 | ||
| 應用說明 | SPI Communication Issue in Wearable Application and Solution Using AFE4xxx in Smart Watch Applications | PDF | HTML | 2025/12/9 | |||
| Product overview | Photoplethysmography (PPG) With Integrated AFE for Optical Biosensing | PDF | HTML | 2023/10/30 | |||
| Application brief | Measuring Oxygen Saturation (SpO2) on Wearables | PDF | HTML | 2022/11/14 | |||
| Application brief | Optical Heart Rate Monitoring (OHRM) on Wearables | PDF | HTML | 2022/11/14 |
設計與開發
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AFE4432EVM — 適用於超小型、超低功耗、高 SNR、整合式 AFE 的 AFE4432 評估模組
AFE4432 評估模組 (EVM) 是評估 AFE4432 的平台，此為光學生物感測應用領域的類比前端 (AFE)，如心率監控 (HRM) 與周邊微血管氧飽和度 (SpO2)。AFE4432 支援多達四個切換發光二極體 (LED) 和多達三個光電二極體 (PD)。AFE 配備兩個具 8 位元電流控制功能的 LED 驅動器。
| 封裝 | 針腳 | CAD 符號、佔位空間與 3D 模型 |
|---|---|---|
| DSBGA (YCH) | 25 | Ultra Librarian |
訂購與品質
建議產品可能具有與此 TI 產品相關的參數、評估模組或參考設計。