No optics tests
No optics (laser lens, APD lens, mirror) is installed. Optics holders are present. Laser and APD are directed upwards.
Be careful - additional background light could increase noise - is good seen at histogram.
Signal is measured at TIA positive output (J1 connector).
The tests below are done with AD500-8, other APDs should have same results (taking into account that they have another breakdown voltage).
PCB v1 (AD500-8); APD voltage - 88.5V (close to breakdown, so gain is >80)
PCB v1 (AD500-8); Laser voltage - 14V; White object distance - 1.8m
APD voltage - 60V, TIA positive output signal amplitude = ~25 mV.
APD voltage - 65V, TIA positive output signal amplitude = ~28 mV.
APD voltage - 70V, TIA positive output signal amplitude = ~35 mV.
APD voltage - 75V, TIA positive output signal amplitude = ~41 mV.
APD voltage - 80V, TIA positive output signal amplitude = ~52 mV.
APD voltage - 85V, TIA positive output signal amplitude = ~70 mV.