My customer is considering the LTC2900. I got a question there.
About voltage threshold programming.
Datasheet P.9 states that VPG / VREF has an error of ± 0.01.
Since we use MODE11 this time, VPG / VREF = 0.719 for 28kΩ and 71.5kΩ. Because it is ± 0.01,
it is considered to be within 0.718 to 0.720, taking into account the error of VREF and the resistance error.
However, using the 1% error resistance to calculate the worst case does not fall within this range.
R1 (-1%) = 28 kΩ * 0.99 = 27720 Ω
R2 (+ 1%) = 71.5 kΩ * 1.01 = 72215 Ω
VPG = VREF (typ) * (R2 / (R1 + R2))
VPG / VREF = 0.7226
It becomes the above calculation result and it does not fit in VPG / VREF (± 0.01).
Is the calculation method wrong?
Or does it differ by ± 0.01?