Overview
The Texas Instruments AFE4400RHAR is a fully-integrated analog front-end (AFE) designed specifically for heart-rate monitors and low-cost pulse oximeters. This device combines a low-noise receiver channel with an integrated analog-to-digital converter (ADC), an LED transmit section, and comprehensive diagnostics for sensor and LED fault detection. The AFE4400RHAR offers flexible pulse sequencing and timing control, making it highly configurable to meet various application requirements. It also includes an integrated oscillator that functions from an external crystal to provide a low-jitter clock, and it communicates with external microcontrollers or host processors via an SPI™ interface. The device is packaged in a compact VQFN-40 package (6 mm × 6 mm) and operates over a temperature range of 0°C to 70°C.
Key Specifications
| Parameter | Specification |
|---|---|
| Package | VQFN-40 (6 mm × 6 mm) |
| Pins | 40 |
| Operating Temperature Range | 0°C to 70°C |
| Supply Voltage (Rx) | 2.0 V to 3.6 V |
| Supply Voltage (Tx) | 3.0 V to 5.25 V |
| Dynamic Range | 95 dB |
| LED Current | Programmable to 50 mA with 8-Bit Current Resolution |
| Power Consumption | < 670 µA at 3.3-V Supply |
| ADC Resolution | 13 Noise-Free Bits |
| Communication Interface | SPI™ |
Key Features
- Fully-integrated analog front-end for pulse oximeter applications
- Flexible pulse sequencing and timing control
- Integrated LED driver (H-Bridge, Push, or Pull)
- Programmable LED on-time and independent LED current references
- Low power consumption: 100 µA + Average LED Current
- Integrated digital ambient estimation and subtraction
- Flexible receive sample time and transimpedance amplifier with programmable LED settings
- Comprehensive fault diagnostics: photodiode and LED open and short detection, cable on and off detection
Applications
The AFE4400RHAR is ideally suited for heart-rate monitors and low-cost pulse oximeters. Its integrated features and low power consumption make it a versatile solution for various medical and health monitoring devices that require accurate and reliable pulse oximetry measurements.
Q & A
- What is the primary application of the AFE4400RHAR?
The AFE4400RHAR is primarily used in heart-rate monitors and low-cost pulse oximeters. - What type of package does the AFE4400RHAR come in?
The AFE4400RHAR is packaged in a VQFN-40 package (6 mm × 6 mm). - What is the operating temperature range of the AFE4400RHAR?
The operating temperature range is 0°C to 70°C. - How does the AFE4400RHAR communicate with external devices?
The device communicates via an SPI™ interface. - What is the dynamic range of the AFE4400RHAR?
The dynamic range is 95 dB. - Can the LED current be programmed?
Yes, the LED current is programmable to 50 mA with 8-Bit current resolution. - What kind of fault diagnostics does the AFE4400RHAR include?
The device includes diagnostics for photodiode and LED open and short detection, as well as cable on and off detection. - What is the power consumption of the AFE4400RHAR?
The power consumption is less than 670 µA at a 3.3-V supply. - Does the AFE4400RHAR have an integrated oscillator?
Yes, it includes an integrated oscillator that functions from an external crystal. - What is the resolution of the ADC in the AFE4400RHAR?
The ADC resolution is 13 noise-free bits.
