The MAX15059 lists a “resistor-adjustable ultra-fast APD current limit” in the feature set. Does this device actively limit the current delivered to the APD or does this limit just affect the threshold at which ILIM# flag is asserted? **
Answer:There are two current limits inside the MAX15059. The current limit that is set by RLIM to set the ADP current limit threshold. When the current limit threshold that is set by RLIM is exceeded, you get a fault at the ILIM# pin.
The data sheet does not explain the other internal switch current limit. However, there is a formula for the inductor peak current as a function of output current and inductor value. When the inductor peak current ILPEAK exceeds the internal peak switch current (1.2A typ) due to excceding the max output current, the MAX15059 turns off the internal 80V switch.