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App Notes

Software & Driver

 

LJTick-DigitalOut5V

Stock: In Stock
Price: $22.00
LabJack LJTick-DigitalOut5V 5V Digital Output Accessory Compatible with LabJack USB, Ethernet, WiFi DAQ Devices

The LJTick-DigitalOut5V (LJT-DO5V) converts a LabJack's 3.3V digital outputs to 5V digital outputs. This allows a LabJack device to control 5V relays or interface with 5V logic devices/sensors. Read more about controlling relays and connecting 5V signals in this app-note.

  • Output only
  • Source or sink 50mA or more
  • Up to 800kHz
  • Interfacing with 5V logic circuitry

Note: When the LabJack digital I/O is configured as an input, the DigitalOut5V accessory will output logic low.

Common Applications

  • Controlling relays that require 5V logic signals.

Figure 1: LJTick-DigitalOut5V

Figure 2: LJTick-DigitalOut5V with U3-LV

Screw Terminal Descriptions

VS: This is the same 5 volt output as the VS terminals on the LabJack itself. This is an output terminal, not an input. It can be used to provide 5 volt (nominal) power as needed.

GND: Same as LabJack ground (GND).

DOA/DOB: These lines are the converted 5V logic lines.

LJTick-DigitalOut5V Hardware Block Diagram

Figure 3: LJTick-DigitalOut5V Hardware Block Diagram

LJTick-DigitalOut5V Schematic

Figure 4: LJTick-DigitalOut5V Schematic

Specifications

Parameter Conditions Min Typical Max Units
Supply Voltage 3.5 5.25 Volts
Supply Current mA
Operating Temperature -40 80 °C
Logic High VS = 4.8V 4.8 Volts
Logic Low VS = 4.8V 0 Volts
Input to cause Logic high 1.84 Volts
Input to cause Logic Low 1.2 Volts
Rise Time Delay 70 ns
Fall Time Delay 90 ns
Rise Time 380 ns
Fall Time 460 ns
Max Frequency (1) (2) 760 kHz
Logic High with Load

VS = 4.8, 50Ω resistor from DOA to GND

4.1 Volts
Output Drive Current (3) 50 mA

(1) This is the recommended maximum frequency of a square wave of 50% duty cycle if the required output signal needs to get to both 0V and 5V. Faster frequencies will result in the signal not reaching 0V.
(2) An output frequency of 1MHz with both voltage rails being met can be achieved by using a duty cycle of 45%. The output waveform will look like a triangle wave at this point with the specified rise and fall times.
(3) Short circuit current is 120 mA, but useable current varies with how close to rail you need to drive per Figure 13 of the AD8646 datasheet. For example, if driving high and sourcing 50 mA there will be a saturation voltage of about 400 mV so the output will be about 4.6V rather than 5.0V.

For more specifications about the logic gates and Op Amp used in the LJTick-DigitalOut5V look at the following datasheets: