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ATL432LI-Q1: ATL432LI-Q1 - Simulated Iref current is higher than expected

LM
Prodigy 215 points
Part Number: ATL432LI-Q1
Other Parts Discussed in Thread: ATL432LI

Hi there,

I've followed the example in this application note https://www.ti.com/lit/an/slva445/slva445.pdf?ts=1619434599658.

Then, I simulated the circuit with Tina TI. The device regulates the voltage (12.5 V) as expected, independently of the input voltage .

However, I've noticed that the Iref is 0.8 uA and the maximum recommended value is 0.4 uA. 

How can I fix this?

kind regards,

Laura

  • 0
    TI__Intellectual 1135 points

    Hi Laura,

    I'm checking into this behavior of the spice model. Few things to note:

    1. ATL432LI can withstand an abs max of 10 mA reference input current. 
    2. If you reduce R8 to 10k ohm, you'll see the reference current decrease, I suspect that there is another limitation of this particular resistor ratio.

    Thanks for your patience.

    Abhishek

  • 0
    TI__Intellectual 1735 points

    Hi Laura,

    The 0.4uA max is under the condition that R2 is left open meaning that VKA = Vref. See table in section 7.5 and the conditions in it for that 0.4uA to be valid. See below for figures.

    In your circuit, you have a voltage gain, which means that the reference current specification no longer applies. If you are concerned about damaging the part in this operating region, this is something that won't damage the part - per the absolute maximum ratings, Iref needs to be between -5mA and 10mA.