SBAS883A February 2018 – June 2018 OPT3101
PRODUCTION DATA.
Figure 23 shows the illumination driver block diagram. The illumination driver supports three illumination channels. The same current source is multiplexed onto three channels. Only one channel can be used at any given time.
Illumination driver current can be programmed using a 5-bit DAC, listed in Table 7. Step size of the DAC can also be scaled from 1.4 mA to 5.6 mA using ILLUM_SCALE. A dc bias-current option is also provided. DC bias is useful if the system requires a very small switching illumination current. This dc bias can be programmed in the range of 0.5 mA to 7.5 mA in steps of 0.5 mA using ILLUM_DC_CURR_DAC.
REGISTER | ADDRESS | DESCRIPTION |
---|---|---|
EN_LED_DRV | 79h[0] | Enable the illumination driver |
ILLUM_DAC_L_TX0 | 29h[4:0] | Illumination driver-current DAC register, ILLUM_DAC_L of TX0 channel. Illumination current = ILLUM_DAC_L_TX0 × DAC step |
ILLUM_DAC_H_TX0 | 29h[9:5] | Illumination driver current DAC register, ILLUM_DAC_H of TX0 channel. Illumination current = ILLUM_DAC_L_TX0 × DAC step |
ILLUM_SCALE_L_TX0 | 2Bh[18:16] | Scale the illumination current DAC step size for ILLUM_DAC_L_TX0
0: 5.6 mA | 1: 4.2 mA | 2: 2.8 mA | 3: 1.4 mA | Other values: Not valid. |
ILLUM_SCALE_H_TX0 | 2Bh[21:19] | Scale the illumination current DAC step size for ILLUM_DAC_H_TX0
0: 5.6 mA | 1: 4.2 mA | 2: 2.8 mA | 3: 1.4 mA | Other values: Not valid. |
ILLUM_DC_CURR_DAC | 79h[11:8] | Program the illumination driver DC bias current
DC current = 0.5 mA × ILLUM_DC_CURR_DAC |