LED and laser biasing or driving circuits often require accuracy and stability of the luminosity with respect to variation in temperature, electrical conditions, and physical characteristics. This accuracy and stability are most effectively achieved using a precision DAC, such as the DACx3401-Q1. The DACx3401-Q1 have additional features, such as the V_FB pin that compensates for the gate-to-source voltage of the transistor (V_GS) drop and the drift of the MOSFET. The NVM allows the microprocessor to set-and-forget the LED biasing value, even during a power cycle. Figure 9-1 shows the circuit diagram for LED biasing.

Figure 9-1 LED Biasing