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LM334 Quiescent current?

Jake Housley
Intellectual 260 points
Other Parts Discussed in Thread: LM334, LM431

Hello,

I am looking to get a linear voltage value to use as a comparator source. I am thinking using the LM334 with a capacitor should work. I just need to know what the Quiescent current of the LM334 is? I will be using it programmed to the lowest current output of 1uA. Please get back as soon as you can. Thank you,

-Jake

  • 0
    TI__Intellectual 1745 points

    Hi Jake,

    Can you elaborate a little on what you need?  If you are looking for a fixed voltage from a linear regulator to use as a reference, you can use one of the voltage references TI has available.  You can see the portfolio at .

    If you are looking to make a comparator, you could use an adjustable shunt reference, such as the LM431, and drive the feedback pin with the comparator input signal.  Figure 16 in the datasheet (copied below) shows the schematic to do this.

    Let me know if you have more questions. 

    Thanks,

    Chris

  • 0 in reply to Christopher Dean
    TI__Intellectual 1745 points

    To answer your question about the LM334, the Iq is the "Set Current" that is set by the external resistor.  When you add the resistor between R and V-, you are setting the total current through the device.   Iset at room temp is approximately

    Iset = 64mV*1.059 / Rset

    Iset = 67.7mV / Rset

    Rset = 67.7mV / Iset

    This screenshot is from the LM334 datasheet, where VR = 64mV at room temp (~214uV / Kelvin)

    Chris

  • 0 in reply to Christopher Dean
    Intellectual 260 points
    Hello Chris,

    Thank you for verifying that. What I am trying to do is the following:

    I need a ramp function that consumes very low power (<5uA). I need this ramp to start on a positive pulse. It needs to get to 2.05V in 400 us linearly so I was going to use the constant voltage source to charge a capacitor.

    The new problem I have with the LM334 is the turn on time. I will have to have the LM334 turned on but I have to figure out how to not charge the capacitor until the positive pulse comes...

    I appreciate any suggestions. Thank you,

    -Jake