The AFE4900 device is an analog front-end (AFE) for synchronized electrocardiogram (ECG), photoplethysmogram (PPG) signal acquisition. The device can also be used for optical bio-sensing applications, such as heart-rate monitoring (HRM) and saturation of peripheral capillary oxygen (SpO2). The PPG signal chain supports up to four switching light-emitting diodes (LEDs) and up to three photodiodes (PDs). The LEDs can be switched on using a fully integrated LED driver. The current from the photodiode is converted into voltage by the transimpedance amplifier (TIA) and digitized using an analog-to-digital converter (ADC). The ECG signal chain has an instrumentation amplifier (INA) with a programmable gain that interfaces to the same ADC. A right-leg drive (RLD) amplifier set can be used to the bias for the ECG input pins. AC and dc lead-off detect schemes are supported. The ADC codes from the PPG and ECG phases can be stored in a 128-sample first in, first out (FIFO) block and read out using either an I2C or a serial programming interface (SPI) interface.
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|Part number||Order||Number of input channels||Resolution (Bits)||Interface||Number of LEDs||Features||Operating temperature range (C)||Package Group||Package size: mm2:W x L (PKG)||Approx. price (US$)|
|4||Optical biosensing||-20 to 70||2.75 | 1ku|
||1||22||SPI||3||Optical biosensing||-20 to 70||DSBGA | 36||36DSBGA: 11 mm2: 3.25 x 3.25 (DSBGA | 36)||3.25 | 1ku|
||1||24||I2C||3||Optical biosensing||-20 to 70||DSBGA | 15||See datasheet (DSBGA)||2.28 | 1ku|
|AFE4405||Samples not available||2||24||
|3||Optical biosensing||-20 to 70||2.50 | 1ku|
|AFE4410||Samples not available||3||24||
|4||Optical biosensing||-20 to 70||2.65 | 1ku|
||1||22||Serial SPI||2||Optical biosensing||-40 to 85||VQFN | 40||40VQFN: 36 mm2: 6 x 6 (VQFN | 40)||7.95 | 1ku|