Measurement Computing USB-1208FS-Plus - Manual (Page 24)

USB-1208FS-Plus User's Guide Specifications
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External trigger
Table 12. Digital trigger specifications
Parameter Specification
Trigger source (Note 7) External digital; TRIG_IN terminal
Trigger mode Edge sensitive; software-selectable for CMOS compatible rising or falling edge, high
or low level.
Trigger latency 10 µs max
Trigger pulse width 1 µs min
Input type Schmitt trigger, 47 kΩ pull-down to ground
Schmitt trigger hysteresis 1.01 V typ
0.6 V min
1.5 V max
Input high voltage threshold 2.43 V typ
1.9 V min
3.1 V max
Input high voltage limit 5.5 V absolute max
Input low voltage threshold 1.42 V typ
1.0 V min
2.0 V max
Input low voltage limit –0.5 V absolute min
0 V recommended min
External clock input/output
Table 13. External clock I/O specifications
Parameter Condition Specification
Terminal name SYNC
Terminal type Bidirectional
Direction
(software-selectable) Output Outputs the internal A/D pacer clock
Input (default) Receives A/D pacer clock from external source
Input clock rate 50 kHz, max
Clock pulse width Input mode 1 µs min
Output mode 5 µs min
Input type Schmitt trigger, 47 kΩ pull-down to ground
Schmitt trigger hysteresis 1.01 V typ
0.6 V min
1.5 V max
Input high voltage threshold 2.43 V typ
1.9 V min
3.1 V max
Input high voltage limit 5.5 V absolute max
Input low voltage threshold 1.42 V typ
1.0 V min
2.0 V max
Input low voltage limit –0.5 V absolute min
0 V recommended min
Output high voltage 4.4 V min (IOH = –50 µA)
3.80 V min (IOH = –8 mA)
Output low voltage 0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 8 mA)