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When using the PTH08T220W, observe the minimum ESR of the entire output capacitor bank. The minimumESR limit of the output capacitor bank is 7m?.
When using the PTH08T221W without the TurboTrans feature, the maximum amount of capacitance is 3000µFof ceramic type. Large amounts of capacitance may reduce system stability.
The PTH08T221W requires a minimum input capacitance of 300µF of ceramic type.The PTH08T220W requires a combination of one 22µF X5R/X7R ceramic and 330µF electrolytic type.
If the TurboTrans feature is not used, minimum ESR and maximum capacitor limits must be followed. Systemstability may be effected and increased output capacitance may be required without TurboTrans.
Generally, with load steps greater than 100A/µs, addingmultiple 10µF ceramic capacitors plus 10×1µF, and numerous high frequency ceramics (?0.1µF) is all that isrequired to soften the transient higher frequency edges.
I emailed TI tech support about the loss of capacitance due to DC bias voltage, he said "Input Large Ceramic capacitors have DC bias voltage drift and temperature up to worst case 30% of each capacitor. This lower total input capacitance is considered when determining minimum operating input ceramic capacitance."
hi mamu, what trimmer resistor value should i use if i want a voltage output of 2.85v - 5.50v with this chip? :think:
I'm only going to make a few mods with this converter, Craig. With the extra cost of the caps, the N-FET, and the hassle of extra wiring it's not really a feasible converter for us.