Micrel, Inc.
MIC2544A/2548A
Figure 7. Flag Filter with COUT = 100µF
USB Power Distribution
The MIC2544A is ideal for meeting USB power
distribution requirements. Figure 8 depicts a USB Host
application. RSET should be set to a value providing a
current-limit >500mA.
The accurate current-limit of the MIC2544A will reduce
power supply current requirements. Also, fast reaction to
short circuit faults prevent voltage droop in mobile
PC applications.
Printed Circuit Board Hot-Plug
The MIC2544A/48A are ideal inrush current-limiters
suitable for hot-plug applications. Due to the integrated
charge pump, the MIC2544A/48A presents high
impedance when off and slowly becomes low impedance
as it turns on. This “soft start” feature effectively isolates
power supplies from highly capacitive loads by reducing
inrush current during hot-plug events. Figure 9 shows
how the MIC2544A may be used in a hot-plug
application.
M9999-043010
April 2010
17
MICREL [ MICREL SEMICONDUCTOR ]
