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Electrical Characteristics of Digital Inputs

USB-I/O adapter digital input pins have either TTL or Schmitt Trigger buffer. Refer to I/O Pinout table to determine the input type for each specific pin.

Electrical characteristics of digital input pins are specified in the following table:

Characteristic Min Max Units Condition
Digital input low voltage:        
Pins with TTL buffer VSS 0.8 V JP3 open
VSS 0.5 V JP3 close
Pins with Schmitt Trigger buffer VSS 1.0 V JP3 open
VSS 0.66 V JP3 close
Digital input high voltage:        
Pins with TTL buffer 2.0 5.0 V JP3 open
1.65 3.3 V JP3 close
Pins with Schmitt Trigger buffer 4.0 5.0 V JP3 open
2.65 3.3 V JP3 close
Input leakage current - ±1 µA

VSS ≤ VPIN ≤ VDD

pin at high-impedance