Hello Daniel,
Thanks you for the comments about table value of Iss and the Iss vs. temperature graph (pg.12, fig.10) – now I can use not absolute values of Iss but normalized values.
But I’m not agree with the idea about Tss growing with temperature decreasing.
Let’s make some speculations:
- Based on Fig.10 on Page 12: Iss at temperature of -25C has 95% of nominal value.
- Css is decreasing at -25C (based on 04023D104K2AT datasheet) – it has -10% of nominal value (so it will be 90% of nominal capacitance).
- Dependence of Vref by temperature is marked in “Electrical Chars.” tablet at page 8 of TPS50601-SP datasheet.
- As a result: The Css and Vref are in the numerator of equation (7) on page 20 of datasheet and Iss is in the denominator.
At -25C we will see:
Css = 0.9*Css (+25C), Vref can be not higher (see table), Iss = 0.95*Iss (+25C).
At the result we will have: 0.9*1/0.95 = 0.947 – so the multiplier for tss at -25C is less then “1” (in comparison of +25C) – so tss at -25C just CAN’T BE HIGHER then at +25C.
But in reality we see 60ms at -25C instead of 40ms at +25C…
Why is this?
And the last question: is our schematic good or you will recommend as to change something?
