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TLV62085: Discrepancy between datasheet and WEBENCH for IC feedback tolerance spec.

Ben G
Prodigy 110 points
Part Number: TLV62085
Other Parts Discussed in Thread: TPS62A01

Hello,

For context, I plan on using the TLV62085RLT voltage regulator to power a device with a stringent voltage regulation requirement of +/-3%. The datasheet of the regulator notes that the feedback regulation voltage (VFB) is spec'd for a min of 792mV, a nominal of 800mV, and a max of 808mV at Tj = 0C to 85C. However, on WEBENCH, the tolerance is set to 20mV regardless of the regulator's junction temperature. 

1. What is the reason for the difference in tolerance between the datasheet and the simulation tool?

2. Is the tolerance on WEBENCH for the entire junction temperature range of the regulator (-40C to 150C)? In some cases, the junction of the regulator I'm using will approach 90C.

  • 0
    TI__Mastermind 18940 points

    Hello Ben, 

    Thank you for using E2E.

    I will update you tomorrow.

    Regards,

    Moheddin.

  • 0 in reply to Moheddin Pasha Shaik
    TI__Mastermind 18940 points

    Hello Ben,

    Apologies for the delay response,

    The 1% shown in the datasheet is the feedback accuracy which relates with the average Vout accuracy and it also depends upon the tolerance of the feedback resistors you are using in your design.

    Ben G said:
    However, on WEBENCH, the tolerance is set to 20mV regardless of the regulator's junction temperature. 

    I didn't get your point, are you referring the output voltage ripple here? please clarify. if you are referring the Vout ripple again it depends upon your operating conditions and also the output capacitor.

    Please provide me your operating conditions and send me the picture what you are referring in the WEBENCH.

    Thank you,

    Regards,

    Moheddin.

  • 0 in reply to Moheddin Pasha Shaik
    Prodigy 110 points

    Hello Moheddin,

    Yes, the Vout accuracy is the point of concern. I'm using 0.1% resistors for the feedback network so my output tolerance should be 1.2%. On WEBENCH the feedback tolerance is 20mV for the regulator (Figure 2) and the Vout tolerance is 2.66% (Figure 3). The output voltage ripple is not what I'm concerned about. Just the output voltage tolerance. I'm operating at 5V input, 3.3V output with 0.5A load. 

    Figure 1: Simulated Circuit.

    Figure 2: IC Feedback Tolerance

    Figure 3: Output Voltage Tolerance

  • 0 in reply to Ben G
    TI__Mastermind 18940 points

    Hello Ben,

    Ben G said:
    I'm using 0.1% resistors for the feedback network so my output tolerance should be 1.2%.

    Yes you are correct, it should be the maximum tolerance. But generally it depends upon the operating conditions as well. The feedback tolerance shown in the datasheet is when the device is operating in PWM mode. 

    Ben G said:
    On WEBENCH the feedback tolerance is 20mV for the regulator (Figure 2) and the Vout tolerance is 2.66% (Figure 3).

    I need to check with the WEBENCH team with this value because it looks too much for me.

    If your load current is 0.5A why don't you try our latest value line hero product - TPS62A01/2 (TPS62A01 data sheet, product information and support | TI.com) it also available in 2A version.

    Thank you,

    Regards,

    Moheddin

  • 0 in reply to Moheddin Pasha Shaik
    TI__Mastermind 18940 points

    Hello Ben,

    If you don't have any further can you please close the thread by clicking on Resolved.

    Thank you,

    Regards,

    Moheddin.