OMB-DAQ-2408 Series User's Guide
Specifications
28
Parameter
Specifications
Input low voltage
1.5 V max, 0.6 V min
Schmitt trigger hysteresis
0.4 V min, 1.2 V max
Note 2:
DGND pins are recommended for use with digital input and digital output pins. The DGND and
AGND pins are common and are isolated from earth ground.
Table 19. Digital output specifications
Parameter
Specifications
Number of I/O
8 channels
Configuration (Note3)
Each DIO bit can be independently read from (DIN) or written to (DOUT).
The DIN bits may be read at any time whether the DOUT is active or tri-stated
Output characteristics (Note 4)
47 kΩ pull-up, open drain (DMOS transistor)
Pull-up configuration
All pins pulled up to +5 V via individual 47 kΩ resistors (the J6 shorting block default
position is pins 1 and 2).
Transfer rate (software paced)
Digital output – 500 port writes or single-bit writes per second typ.
Output voltage range
0 V to +5 V (no external pull up resistor, internal 47 kΩ pull-up resistors connected to
+5 V by default)
0 V to +15 V max (Note 5)
Drain to source breakdown
voltage
+50 V min
Off state leakage current
(Note 6)
1.0 µA
Sink current capability
150 mA max (continuous) per output pin
150 mA max (continuous) for all eight channels
DMOS transistor on-resistance
(drain to source)
4 Ω
Note 3:
DGND pins are recommended for use with digital input and digital output pins. The DGND and
AGND pins are common and are isolated from earth ground.
Note 4:
Each DMOS transistor source pin is internally connected to DGND.
Note 5:
The external pull-up is connected to the digital output bit through an external pull-up resistor. Adding
an external pull-up resistor connects it in parallel with the internal 47 kΩ pull-up resistor of that
particular digital input/output bit. Careful consideration should be made when considering the external
pull-up resistor value and the resultant pull-up voltage produced at the load.
Note 6:
Does not include the additional leakage current contribution that may occur when using an external
pull-up resistor.
Counter
Table 20. CTR specifications
Parameter
Conditions
Specification
Pin name
CTR0, CTR1
Number of channels
2 channels
Resolution
32-bits
Counter type
Event counter
Input type
Schmitt trigger, rising edge triggered
Input source
CTR0 (pin 44)
CTR1 (pin 42)
Counter read/writes rates
(software paced)
Counter read
System dependent, 500 reads per second.
Counter write
System dependent, 500 writes per second.
Input characteristics
Each CTRx input pin
562 kΩ pull-up resistor to +5 V, 10 kΩ series
resistor
Input voltage range
±15 V max
