MB3785A Datasheet, PDF (20/29 Pages) Fujitsu Component Limited. – Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)

MB3785A
<Precautions>
When the oscillation rise time at power switch-on is compared between a ceramic and a crystal resonator, it is
known that the crystal resonator is about 10 to 100 times slower to rise than the ceramic resonator. Therefore, when
a crystal resonator is used, system operation as a switching regulator at power switch-on becomes unstable. To
avoid this problem, it is recommended that you use a ceramic oscillator because it has a short rise time and, hence,
ensures stable operation.
• Crystal Resonator Turn-on Characteristic
2.0
1.5
1.0
0
1
2
3
4
5
t (msec)
• Ceramic Resonator Turn-on Characteristic
2.0
1.5
1.0
0
1
2
3
4
5
t (msec)
20