ZHCSP07A October 2021 – October 2024 ADC12DJ800 , ADC12QJ800 , ADC12SJ800
PRODUCTION DATA
An example list of LiDAR system requirements and the resulting digitizer requirements is given in Table 7-1. The example system requirements are for a mechanically rotating LiDAR system using a spinning mirror to cover the horizontal (azimuth) field-of-view and parallel receivers (photodiodes) to cover the vertical (elevation) field-of-view. The scan time requirement dictates that four vertical points are captured in parallel which requires four ADC channels and therefore a 16:1 photodiode to ADC mux ratio. The long 200 meter range for a 10% reflectivity target requires high performance and therefore a 12-bit ADC is chosen. The minimum pulse width of 5 ns, for high spatial resolution, requires a sampling rate of 800 MSPS in order to get 4 samples of each returning pulse. Low cost and small size are important to enable high volume production and a quad channel ADC with integrated clocking features help drive down these important metrics. Other considerations include the maximum SerDes rate supported by the FPGA and number of lanes. Assume the FPGA has 4 SerDes lanes that support up to 12.5 Gbps. For this reason, JMODE 8 is chosen.
| System Parameter | Example System Requirement | Example Digitizer Requirement |
|---|---|---|
| Maximum Target Range | 200 meters at 10% reflectivity | 12-bit ADC |
| Minimum Laser Pulse Width | 5 ns | 800 MSPS (4 samples per pulse) |
| Horizontal FOV | 360° | See Full Scan Time |
| Vertical FOV | 20° | See Vertical Scanning Method |
| Horizontal Resolution | 0.1° | See Full Scan Time |
| Vertical Resolution | 0.3125° | See Vertical Scanning Method |
| Horizontal Scanning Method | Spinning mirror | See Full Scan Time |
| Vertical Scanning Method | Parallel photodiodes | 64 photodiodes |
| Full Scan Time | 76.8 ms | 16:1 mux ratio (4 ADC channels) |
| System Cost | Low cost | Clock features integrated in ADC |
| System Form Factor | Small form factor | Quad channel ADC with integrated clocking |