The AFE4490 is a fully-integrated analog front-end (AFE) that is ideally suited for pulse-oximeter applications. The device consists of a low-noise receiver channel with a 22-bit 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 device, 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 –40°C to 85°C.
|# Input Channels|
|Sample Rate (max) (SPS)|
|Number of LEDs|
|Operating Temperature Range (C)|
|Package Size: mm2:W x L (PKG)|
|Serial SPI||SPI||SPI||I2C|| I2C |
| SPI |
| SPI |
|-40 to 85||0 to 70||-20 to 70||-20 to 70||-20 to 70||-20 to 70||-20 to 70|
|40VQFN: 36 mm2: 6 x 6(VQFN)||40VQFN: 36 mm2: 6 x 6(VQFN)||See datasheet (DSBGA)||See datasheet (DSBGA)|
|Optical biosensing||Optical biosensing||Optical biosensing||Optical biosensing||Optical biosensing||Optical biosensing||Optical biosensing|
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