SBAS883A February 2018 – June 2018 OPT3101
PRODUCTION DATA.
The OPT3101 device requires 1.8-V and 3.3-V supplies. There are two 1.8-V supplies (AVDD and DVDD) and two 3.3-V supplies (AVDD3 and IOVDD). AVDD and AVDD3 are analog supplies, DVDD and IOVDD are digital and I/O supplies. VDD_LED is not a device pin, but the supply connecting to the anode of the LED (Illumination source). The inimum voltage of the VDD_LED supply is 0.7 V (VDRV) + forward voltage drop of the LED at the maximum illumination driver current (1.8-V typical for 850-nm LED with 100 mA) + IR drop across the series elements (beads, PCB routing) in the supply (VDD_LED) – ground (VSSL) path. The transmitter and receiver of the OPT3101 device operate at the same modulation frequency (10 MHz). Any coupling from the transmitter switching to the AFE results in a crosstalk signal which affects the performance of the distance measurement. Achieving the lowest possible crosstalk is critical for an accurate distance measurement system. Care should be taken to isolate all analog and switching supplies. VDD_LED has the highest switching current at the modulation frequency, fMOD. DVDD and IOVDD also have switching current at the modulation frequency, fMOD, but much lower than VDD_LED. Use ferrite beads with the highest impedance at 10 MHz (> 500 Ω) in the series path of the supplies and decoupling capacitors with low impedance at fMOD on the supplies very close to the device.