Open collector/drain troubles

  • Thread starter Ja4Coltrane
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In summary, the speaker is having issues with using a DS92LV010A transceiver between an I2C slave temperature detector and a digital circuit. The transceiver is set for driver input but is pulling the voltage of the SDA line down too strongly for the required pullup resistor to counteract. The speaker is wondering if it is possible to use this transceiver for open drain and if more information would make their question more answerable. A schematic is also requested for better understanding of the situation.
  • #1
Ja4Coltrane
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Hi everyone.

I have a digital circuit which is supposed to talk to a temperature detector. The detector speaks open drain I2C (and it is a slave of course).

My problem is not with I2C but is instead the following. The data line for the detector is, on the other side, the driver input and receiver output of a differential / single ended transceiver, the DS92LV010A (www.national.com/ds/DS/DS92LV010A.pdf[/URL]). By the way, I didn't build this PCB, I'm just trying to use it.

When the transceiver is set for driver input (input from the detector), I have found that it pulls the voltage of the SDA line down to 0 more strongly than the required pullup resister can counteract.

Is it impossible to use this transciever for open drain?
Please let me know if more information would make my question more answerable.

Thanks
 
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  • #2
A schematic would help... I'm also confused about the directions of things. You say:
"When the transceiver is set for driver input (input from the detector)...it pulls the voltage of the SDA line down..." If it's an input it shouldn't be pulling anything down, or is the SDA line on the output of the transceiver that is trying to do input? If so, it should eventually also pull up, no? And I'm not clear where the open-collector thing comes into play.

Schematic schematic schematic...
 
  • #3
Ja4Coltrane said:
Hi everyone.

I have a digital circuit which is supposed to talk to a temperature detector. The detector speaks open drain I2C (and it is a slave of course).

My problem is not with I2C but is instead the following. The data line for the detector is, on the other side, the driver input and receiver output of a differential / single ended transceiver, the DS92LV010A (www.national.com/ds/DS/DS92LV010A.pdf[/URL]). By the way, I didn't build this PCB, I'm just trying to use it.

When the transceiver is set for driver input (input from the detector), I have found that it pulls the voltage of the SDA line down to 0 more strongly than the required pullup resister can counteract.

Is it impossible to use this transciever for open drain?
Please let me know if more information would make my question more answerable.

Thanks[/QUOTE]

Are you trying to put that LVDS transceiver between your I2C slave temperature sensor and your I2C master uC?
 
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1. What is an open collector/drain?

An open collector/drain is a type of output circuit used in electronic devices. It consists of a transistor and a resistor, and allows the device to provide either a low or high voltage output.

2. What are some common troubles associated with open collector/drain circuits?

Some common troubles with open collector/drain circuits include incorrect voltage levels, short circuits, and circuit damage due to incorrect wiring or component failure.

3. How can I troubleshoot open collector/drain problems?

To troubleshoot open collector/drain problems, you should first check the voltage levels and ensure they are within the specified range. Next, check for any short circuits or damaged components. If the problem persists, consult the device's manual or seek assistance from a professional.

4. Can open collector/drain circuits be used in all electronic devices?

Open collector/drain circuits can be used in most electronic devices, but they are not suitable for all applications. It is important to consider the device's requirements and consult the manufacturer's specifications before implementing an open collector/drain circuit.

5. What are the advantages of using open collector/drain circuits?

Open collector/drain circuits offer several advantages, including their ability to provide a wide range of output voltages, their low cost and simplicity, and their compatibility with a variety of devices. Additionally, open collector/drain circuits can be easily customized for different applications.

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