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TPS62170 Vref Accuracy 2

PAN-M
Mastermind 8375 points
Other Parts Discussed in Thread: TPS62170

Dear all.

TPS62170 Vref accuracy typical is 0.8V writen by datasheet.
Do you have min/max parameter?

Parametrics:
Vref Accuracy(Typ)(%) is 3%
Is this the meaning to +/-3%? or +/-1.5%?

EVM;
Output Voltage PWM Mode of Operation 3.227/3.327/3.427 V
Is this a Vref accuracy? or output? full load?

Regards,
PAN-M

  • 0
    TI__Intellectual 2415 points
    Dear PAN-M,

    Internal reference voltage 0.8V is typical value.
    If TPS62170 is operating in PWM mode then variation of the internal reference voltage is +/-3% over free-air temperature range (TA=-40°C to +85°C)
    If TPS62170 is operating in power save mode then variation of the internal reference voltage is -3.5 % up to +4% over free-air temperature range (TA=-40°C to +85°C) for output capacitance 22uF. Output voltage ripple in power save mode can be higher therefore variation is higher.

    EVM:
    Output voltage accrancy 3.227/3.327/3.427 V is variation of the output voltage due to the variation of the internal reference voltage is +/-3% .
    Please see load regulation on page 4 of www.ti.com/.../slvu483.pdf , Figure 3 and line regulation Figure 4.

    Please let me know if you have further questions.

    Best regards

    Lubomir Fenic
  • 0 in reply to Lubomir
    Mastermind 8375 points

    Thank you for reply.

    The output variation voltage of EVM is +/-3% at 25°C ambient temperature, internal reference voltage accuracy is +/-3% at -40 to 85°C.
    I understood.
    However, Figure 3 and 4 of slvu483 regulation is under 1%.
    Which point did this chart measure?

    Regards,
    Pan-M

  • 0 in reply to PAN-M
    TI__Intellectual 2415 points

    Dear PAN-M,

    The output voltage variation of the EVM i caused by several parameters:

    •  Output voltage variation mentioned in EVM: 3.227/3.327/3.427 V is caused by the variation of the internal voltage reference +/-3% at -40°C to +85°C 
    • Load regulation, example of load regulation please find in datasheet TPS62170 page9, Figure 13
    • Line regulation, example of line regulation please find in datasheet TPS62170 page9, Figure 14
    • Tolerance of the resistors connected to feedback pin. More information about effect of resistor tolerances on power supply accuracy please find in:

    Points of measurement are:

    • Input voltage: connector J2
    • Output voltage connector J5

    Which output voltage accuracy would you like to achieve?

    Best regards

    Lubomir Fenic

  • 0 in reply to Lubomir
    Mastermind 8375 points
    Yes, thank you for support.