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LM4040-N: [ELENTEC] Design inquiry when using LM4040AIM3X-3.0/NOPB

MJ Jeon
Genius 5240 points
Part Number: LM4040-N

Hi, TI support team

Inquiries from customers have been received.

[Inquiry about Rs value setting]

When Vs=BAT voltage,

1. How should I set the Rs value when the BAT voltage is 3.2V~4.3V?

In the case of Vs=3.0V (LDO output),

2. Is it okay to use the Voltage Reference IC as the LM4040AIM3X-3.0/NOPB product?

Thanks.

Regards,

MJ

  • 0
    TI__Genius 11071 points

    Hi MJ 

    I assume you are refering RS in below diagram -

    Min and max value of RS will be decided by the VDD range and min and max reverse current (60uA - 15mA){ Section 6.3 recommended operating condition}. 

    RS_MAX = (VDD_min - Vout)/ IR_Min = (3.2 -3)/(60uA) = 3.3k ohm 

    RS_min = (VDD_max - Vout)/ IRmax = (4.3-3)/ 15mA = 86 ohm 

    So you can choose any resistor between 100 ohms to 3K ohms depending on your power budget.  I have reduced the range from both the sides to take care of tolerance. 

    It is completely fine to use Voltage Reference IC as the LM4040AIM3X-3.0/NOPB product. 

    Regards

    Trailokya