Measurement-computing USB-1208HS-4AO Manual do Utilizador descarregar pdf (Página 19)

USB-1208HS-4AO User's Guide Specifications

External trigger

Table 7. External trigger specifications

Parameter Specification

Trigger source TRIG input

Trigger mode Software-selectable for edge or level sensitive, rising or falling edge, high or low level.

Power on default is edge sensitive, rising edge.

Trigger latency 1 µs + 1 clock cycle max

Trigger pulse width 100 ns min

Input type Schmitt trigger, 33 Ω series resistor and 47 kΩ pull-down to ground

Schmitt trigger hysteresis 0.4 V to 1.2 V

Input high voltage 2.2 V min

5.5 V absolute max

Input low voltage 1.5 V max

–0.5 V absolute min

0 V recommended min

External clock input/output

Table 8. External clock I/O specifications

Parameter Specification

Terminal names AICKI, AICKO, AOCKI, AOCKO

Terminal types AxCKI: Input, active on rising edge

AxCKO: Output, power on default is 0 V, active on rising edge

Terminal descriptions AxCKI: Receives sampling clock from external source

AxCKO: Outputs the internal sampling clock (D/A or A/D clock) or pulse generated from

AxCKI when in external clock mode

Input clock rate 1 MHz max

Clock pulse width AxCKI: 400 ns min

AxCKO: 400 ns min

Input type Schmitt trigger, 33 Ω series resistor, 47 kΩ pull-down to ground

Schmitt trigger hysteresis 0.4 V to 1.2 V

Input high voltage 2.2 V min

5.5 V absolute max

Input low voltage 1.5 V max

–0.5 V absolute min

0 V recommended min

Output high voltage 4.4 V min (IOH = –50 µA)

3.76 V min (IOH = –24 mA)

Output low voltage 0.1 V max (IOL = 50 µA)

0.44 V max (IOL = 24 mA)

Output current ±24 mA max per terminal (refer to Power section for additional information)

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