There is a very nice automatic, bidirectional logic-level translator on the TRIG path that virtually ensures a user will not destroy the MCU due to incorrect logic level choice to the TRIG input. However, this device is very bad a driving capacitive loads and will go into an unstable oscillation if, e.g., a long coax is put on the TRIG BNC port when it is used as an output. May need to think of how to buffer the TRIG output when its used to send pulses rather than receive them.
Buffering may not even be necessary -- a series 100 Ohm resistor to decouple the output pin of the ADG3301 from the capacitance of the Coax will probably work in most circumstances at the cost of a slower rise time due to effective RC.
jonnew
commented
7 years ago
There is a very nice automatic, bidirectional logic-level translator on the TRIG path that virtually ensures a user will not destroy the MCU due to incorrect logic level choice to the TRIG input. However, this device is very bad a driving capacitive loads and will go into an unstable oscillation if, e.g., a long coax is put on the TRIG BNC port when it is used as an output. May need to think of how to buffer the TRIG output when its used to send pulses rather than receive them.
Buffering may not even be necessary -- a series 100 Ohm resistor to decouple the output pin of the ADG3301 from the capacitance of the Coax will probably work in most circumstances at the cost of a slower rise time due to effective RC.