Catalog
Integrated Analog Front End (AFE) for Pulse Oximeters
Key Features
• Fully-Integrated Analog Front-End forPulse Oximeter Applications:Flexible Pulse Sequencing andTiming ControlTransmit:Integrated LED Driver (H-Bridge, Push, or Pull)110-dB Dynamic Range Across Full Range (Enables Low Noise at Low LED Current)LED Current:Programmable Ranges of 50 mA, 75 mA, 100 mA, 150 mA, and 200 mA,Each with 8-Bit Current ResolutionLow Power:100 µA + Average LED CurrentLED On-Time Programmability from(50 µs + Settle Time) to 4 msIndependent LED2, LED1 Current ReferenceReceive Channel with High Dynamic Range:Input-Referred Noise:50 pARMS(at 5-µA PD Current)13.5 Noise-Free Bits (at 5-µA PD Current)Analog Ambient Cancellation Scheme with Selectable 1-µA to 10-µA Ambient CurrentLow Power: < 2.3 mW at 3.0-V SupplyRx Sample Time: 50 µs to 4 msI-V Amplifier with Seven Separate LED2 and LED1 Programmable Feedback R and C SettingsIntegrated Digital Ambient Estimation and SubtractionIntegrated Fault Diagnostics:Photodiode and LED Open andShort DetectionCable On or Off DetectionSupplies:Rx = 2.0 V to 3.6 VTx = 3.0 V or 5.25 VPackage: Compact VQFN-40 (6 mm × 6 mm)Specified Temperature Range: –40°C to 85°CFully-Integrated Analog Front-End forPulse Oximeter Applications:Flexible Pulse Sequencing andTiming ControlTransmit:Integrated LED Driver (H-Bridge, Push, or Pull)110-dB Dynamic Range Across Full Range (Enables Low Noise at Low LED Current)LED Current:Programmable Ranges of 50 mA, 75 mA, 100 mA, 150 mA, and 200 mA,Each with 8-Bit Current ResolutionLow Power:100 µA + Average LED CurrentLED On-Time Programmability from(50 µs + Settle Time) to 4 msIndependent LED2, LED1 Current ReferenceReceive Channel with High Dynamic Range:Input-Referred Noise:50 pARMS(at 5-µA PD Current)13.5 Noise-Free Bits (at 5-µA PD Current)Analog Ambient Cancellation Scheme with Selectable 1-µA to 10-µA Ambient CurrentLow Power: < 2.3 mW at 3.0-V SupplyRx Sample Time: 50 µs to 4 msI-V Amplifier with Seven Separate LED2 and LED1 Programmable Feedback R and C SettingsIntegrated Digital Ambient Estimation and SubtractionIntegrated Fault Diagnostics:Photodiode and LED Open andShort DetectionCable On or Off DetectionSupplies:Rx = 2.0 V to 3.6 VTx = 3.0 V or 5.25 VPackage: Compact VQFN-40 (6 mm × 6 mm)Specified Temperature Range: –40°C to 85°C
Description
AI
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.
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.
