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REF3033: adding extra current drive capability externally

Part Number: REF3033

Hello,

1. is there a way to increase current drive by adding an external transistor? if yes, please recommend the circuit

2. IS there any alternate part which is similar with increased current drive in smaller packages

  • Hi Mohammed 

    • You can use a low noise precision buffer (where offset tem drift is low) buffer (opamp) to increase the drive strength. 
    • We have released nano IQ refernce  REF35 is SOT23 package, this is pin compatible with REF30. You can use it with buffer. 

    Regrads

    Trailokya 

  • Just to be on same page, what I'm expecting is this.

    My requirement :I have added new circuitry, new controller in my board. Since REF3033 had output current rating of 25mA, I wanted to increase it by adding an external circuitry. is there a way to do so? if yes, please guide on the circuit.

    What you're suggesting is to use a buffer, can you guide me to a part which can give me some idea to follow through.

  • Hi Mohammed 

    You can look into OPAx310 part. It has 150mA drive capability and have good offset tempdrift and noise. Please add it in non inverting buffer config and this should work. 

    Regards

    Trailokya 

  • are you suggesting something like this?

  • Hi Mohammed 

    This will work. 

    Regards

    Trailokya 

  • Ok Got it.

    Couple of questions:

    1. Do i need to add any resistors at the input terminals of opamp ?

    2. 

    what this statement means? my circuit has bulk capacitances.

    3. Also, since REF3033 does not sink current, Will it have any impact on bias currents flowing from OPA, i'm just making an absurd statement as it just crossed my mind, Do we have to focus in this area?

  • Below configuration should work 

    Where you can add around 10-20 ohms Riso for stability with  load cap.  

    • There will not be any bias current through the non inverting pin as this pin is HighZ. 

    Regards 

    Trailokya 

  • 3v3_supply.TSC

    1. How to add a pulse current load (to emulate a microcontroller response) in the above file.

    2. How to check the response of the output to see overshoot, and other stuff, i mean what analysis to run? please do explain in brief and plot it in simulation file above

    please guide...

  • Hi Mohammed 

    You can add a resistor (based on your load condition) with a fuction gerenaror and give a  pulse of 0 to 3.3V. This will tell you the trasient behaviro of the device - 

    Regards 

    Trailokya 

  • 1. Hello, can you help me with the transient response in the simulation file attached. Please Set the timing and analysis so that i can observe.

    3v3_supply - autosave 23-01-06 01_02.TSC

    OPA310 doesn't seem to be available anywhere.

    2. Can you suggest an equivalent opamp or a better opamp which is available?

    3. Also, can i use LMV861MG/NOPB? What are the impacts

  • Hi Mohammed 

    Here is your file. 

    REF3033).TSC

    10 ohm seriese  resistor may give you huge swing in the output . 

    I am transfering this to amplifier forum , they will suggest you correct opamp. 

    Hi Amp experts 

    We need a buffer which can support upto 100mA load swing for 50uF capacitor with good accuracy. Can you please suggest some opamp. 

    Regards 

    Trailokya 

  • Hi Mohammed,

    I'm seeing on TI.com we do have a lot of OPA310 stock. Are you looking on TI.com? 

    Best Regards,

    Robert Clifton 

  • Our outsource partner buys from mouser / Digi key. 

    Questions:

    1. As per Trailokya's post above, we need a buffer which can support up to 100mA load swing for 50uF capacitor with good accuracy. So is there a part which can perform this requirement or are suggesting OPA itself will do the work

    2.  Also, if you are suggesting an alternate part, suggest a part which can be procured through mouser / Digi key.

  • Hi Mohammed,

    While I will continue to recommend OPA310 when it gets stocked, since it's the newest and has the best specs, I think the TLV341 would be a good alternative, though it's right at the edge of the 100mA requirement. The LMV861 would likely be another good fit in this application and have more output current margin than the TLV341. 

    Best Regards, 

    Robert Clifton