User manual

Chapter 3 Signal Connections
© National Instruments Corporation 3-7 PC-DIO-96/PnP User Manual
Digital I/O Signal Connections
Pins 1 through 48 and pins 51 through 98 of the I/O connector are digital
I/O signal pins. The following specifications and ratings apply to the
digital I/O lines.
Absolute maximum voltage rating -0.5 to +5.5 V with respect to GND
Digital input specifications (referenced to GND):
Input logic high voltage 2.2 V min 5.3 V max
Input logic low voltage -0.3 V min 0.8 V max
Maximum input current
(0 < V
in
< 5 V) -1.0 µA min 1.0 µA max
Digital output specifications (referenced to GND):
Output logic high voltage 3.7 V min 5.0 V max
at I
out
= -2.5 mA
Output logic low voltage 0.0 V min 0.4 V max
at I
ou
t
= 2.5 mA
Output current 2.5 mA min —
at V
OL
= 0.5 V
Output current 2.5 mA min —
at V
OH
= 2.7 V
Figure 3-4 depicts signal connections for three typical digital I/O
applications.