MIC2202_07 Datasheet, PDF (9/19 Pages) Micrel Semiconductor – High Efficiency 2MHz Synchronous Buck Converter 1μF Stable PWM Regulator

Micrel, Inc.
PWM control provides fixed frequency operation. By
maintaining a constant switching frequency, predictable
fundamental and harmonic frequencies are achieved.
Other methods of regulation, such as burst and skip
modes, have frequency spectrums that change with load
that can interfere with sensitive communication equip-
ment.
Synchronization
Sync_In allows the user to change the frequency from
2MHz up to 2.5MHz or down to 1.6MHz. This allows the
ability to control the fundamental frequency and all the
resultant harmonics. Maintaining a predictable frequency
MIC2202
creates the ability to either shift the harmonics away
from sensitive carrier and IF frequency bands or to
accurately filter out specific harmonic frequencies.
The Sync_Out function pin allows for the ability to be
able to sync up multiple MIC2202s in a “daisy-chain”,
connecting Sync_Out to Sync_In of the other MIC2202.
Synchronizing multiple MIC2202s benefits much in the
same way as syncing up one MIC2202. All regulators
will run at the same fundamental frequency, resulting in
matched harmonic frequencies, simplifying designing for
sensitive communication equipment.
MIC2202
“Master”
VIN
SW
BIAS
SYNC_IN
SYNC_OUT
FB
MIC2202
“Slave”
VIN
SW
BIAS
SYNC_IN
SYNC_OUT
FB
Figure 4. Master-Slave Operation
March 2007
Figure 5. Master-Slave Synchronization Waveforms
9
M9999-031907