XC9505 datasheet(13/50 Pages) TOREX

13 / 50 page

13/50

XC9505

Series

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NOTES ON USE

1. Checking for Intermittent Oscillation

The XC9505 series is subject to intermittent oscillation in the proximity of the MAX. duty if the step-down ratio is low (e.g.,

from 4.2 V to 3.3 V) or a heavy load is applied where the duty ratio becomes high. Check waveforms at EXT under your

operating conditions. A remedy for this problem is to raise the inductance of coil L or increase the load capacitance CL.

2. PWM/PFM Automatic Switching

If PWM/PFM automatic switching control is selected and the step-down ratio is high (e.g., from 10.0 V to 1.0 V), the control

mode remains in PFM setting over the whole load range, since the duty ratio under continuous-duty condition is smaller

than the PFM duty ratio of the XC9505series. The output voltage's ripple voltage becomes substantially high under

heavy load conditions, with the XC9505 series appearing to be producing an abnormal oscillation. If this operation

becomes a concern, set pins PWM to High to set the control mode to PWM setting. For use under the above-mentioned

condition, measured data of PWM/PFM automatic switching control shown on the data sheets are available up to IOUT =

100 mA.

3. Ratings

Use the XC9505 series and peripheral components within the limits of their ratings.

XC9505 Datasheet(PDF) 13 Page - Torex Semiconductor