MP1583 – 3A, 23V, 385KHz STEP-DOWN CONVERTER
External Bootstrap Diode
C4
C3
R3
R4
An external bootstrap diode may enhance the
efficiency of the regulator, the applicable
conditions of external BST diode are:
C6
z
z
VOUT=5V or 3.3V; and
Duty cycle is high: D=
SGND
VOUT
VIN
>65%
In these cases, an external BST diode is
recommended from the output of the voltage
regulator to BST pin, as shown in Fig.4
C2
L1
External BST Diode
IN4148
BST
C1
CBST
D1
MP1583
5V or 3.3V
SW
PGND
C5
+
COUT
L
Top Layer
Figure 4—Add Optional External Bootstrap
Diode to Enhance Efficiency
The recommended external BST diode is
IN4148, and the BST cap is 0.1~1µF.
Bottom Layer
Figure 3―PCB Layout (Double Layer)
MP1583 Rev. 3.1
6/20/2011
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