SC4210AEVB View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
SC4210AEVB Datasheet PDF : 11 Pages
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POWER MANAGEMENT
Applications Information (Cont.)
SC4210A
Figure 4.
Figure 6.
Figure 5 shows the transient response for the circuit
described above – the ripple Vpk-pk is almost 60mVpk-
pk, which is a result of the overdamped system.
Figure 7. is an example of how close the actual results
can be obtained with the simulation once the correct
model has been defined. Below is the P-Spice simulation
of the circuit which was built and tested with Ridley
instrument; see Figure 6.
Figure 5.
Figure 7.
This circuit can be modified to improve transient
performance. This can be achieved by raising Rcomp until
the PM decreases to 50-60º at unity gain crossover. This
is achieved by raising Rcomp to approximately 5.6kΩ,
which gives a PM of 50º at a unity gain of 1MHz; see
Figure 6 for the actual circuit Bode plot taken with Ridley
Instrument.
Again, we achieved a respectable transient response,
VOUT_RIPPLE < 50mVpk-pk, less then 3% of the VOUT = 1.8V;
see Figure 8.
2004 Semtech Corp.
8
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