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Ultra-small integrated AFE with FIFO for multisensor wearable optical heart-rate monitoring

Availability: 1,015


Package | PIN: DSBGA (YZ) | 30
Temp: I (-40 to 85)
Carrier: Cut Tape
Qty Price
1-9 $9.09
10-24 $8.18
25-99 $7.63
100-249 $6.85
250-499 $6.39
500-749 $5.56
750-999 $4.81
1,000+ $4.72


  • Supports signal acquisition of up to 16 phases
  • Flexible allocation of LEDs and PDs in each phase
  • Accurate, continuous heart-rate monitoring:
    • Up to 100-dB dynamic range
    • Low current for continuous operation on a wearable device with a typicalvalue
      • 15 µA for an LED, 20 µA for the receiver
  • Transmitter:
    • Supports common anode LED configuration
    • 8-Bit programmable LED current with range adjustable from 50 mA to 200mA
    • Mode to fire two LEDs in parallel
    • Programmable LED on-time
    • Simultaneous support of 4 LEDs for optimized SpO2, HRM, or multi-wavelength HRM
    • Programmable control signals to extend operation to 8LEDs using external SPDT switches
  • Receiver:
    • Supports 4 time-multiplexed photodiodeinputs
    • Individual DC offset subtraction DAC at TIA inputfor each LED, ambient with 7-bit control and range up to ±254 µA
    • Transimpedance gain: 10 kΩ to 2 MΩ
    • Digital ambient subtraction at ADC output to suppress ambient tones
    • Noise filtering with programmable bandwidth
  • Supports external clock and internal oscillator modes
  • Automatic ambient cancellation mode (AACM) to increase receiver dynamic range
  • Two programmable GPIO pins with flexible interrupt generation
  • FIFO with 128-sample depth
  • I2C, SPI interfaces: selectable by pin
  • Operating temperature range: –40°C to +85°C
  • 2.6-mm × 2.1-mm DSBGA, 0.4-mm pitch
  • Supplies:
    • Rx:
      • 1.7 V to 1.9 V (LDO bypass)
      • 1.9 V to 3.6 V (LDO enabled)
    • Tx: 3 V to 5.5V
    • IO: 1.7 V to RX_SUP

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Texas Instruments  AFE4420YZT

The AFE4420 is an analog front-end for optical bio-sensing applications, such asheart-rate monitoring (HRM) and saturation of peripheral capillary oxygen (SpO2). The devicesupports up to four switching light-emitting diodes (LEDs) and up to four photodiodes. Up to 16signal phases can be defined and the signal can be acquired from each phase in a synchronizedmanner and stored in a 128-sample First in, First out (FIFO) block. The FIFO can be read out usingeither an I2C or a SPI interface. The AFE also has a fully integrated LED driver with an 8-bitcurrent control. The device has a high dynamic range transmit-and-receive circuitry that helps withthe sensing of very small signal levels.