LJTick-OutBuff Datasheet
The LJTick-OutBuff (LJTOB) is an output buffer tick that increases the output current of the DAC outputs on LabJack devices. The LJTick-OutBuff can also be used to increase the output abilities of the devices digital I/O lines by switching 3.3V logic. LabJack devices cannot output more than about 15mA on their DAC0 and DAC1 analog outputs so this accessory is helpful for users who want to increase that capability. One common application is to control the speed of a low voltage DC motor.
Drives up to 200mA
0-5V output range*
* Max voltage depends on the supplied VS line which is 5V nominally.
Common Applications
Controlling LEDs
Generating variable stable excitation voltages
Figure 1: LJTick-OutBuff
Figure 2: LJTick-OutBuff With U3
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).
OBA/OBB: These output lines are generated by the Op Amp and track the input voltage.
LJTick-OutBuff Hardware Block Diagram
Figure 3: LJTick-OutBuff Hardware Block Diagram
LJTick-OutBuff Hardware Block Diagram with Filter
Figure 3: LJTick-OutBuff Hardware Block Diagram with Filter
LJTick-OutBuff Schematic
Figure 3: LJTick-OutBuff Schematic
Specifications
Parameter | Conditions | Min | Typ | Max | Units |
Supply Voltage (VS) |
| 2.5 |
| 6 | V |
Supply Current | No Load |
| 1.0 |
| mA |
Operating Temp |
| -40 |
| 85 | Deg C |
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Max Output Current |
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| ±320 |
| mA |
Short-Circuit Current |
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| 800 |
| mA |
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Max Output Voltage | 10 mA | VS - 0.3 | VS - 0.04 |
| V |
| 200 mA | VS - 0.55 | VS - 0.4 |
| V |
Min Output Voltage | 10 mA |
| 0.03 | 0.1 | V |
| 200 mA |
| 0.38 | 0.6 | V |
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Offset Error |
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| 175 | 3500 | μV |
Gain Error |
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| % |
Output Noise |
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Slew Rate or RC |
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Cutoff Frequency (1) |
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| 39 |
| kHz |
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Capacitive Drive (2) |
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| 1 | nF |
(1) Calculated by passing a 0-5V sine wave and measuring the input/output to get a -3dB difference.
(2) Capacitive loads beyond 1 nF might cause the output to oscillate. Add a 20 Ω series resistor to prevent this.
For more specifications about the Op Amp used in the LJTick-OutBuff refer to the Texas Instruments TLV4112 datasheet.