Diodes AP3421/A/B - Manual (Page 13)

Preliminary Datasheet
1.3MHz, Dual 1.0A Synchronous Step-down Converters AP3421/A/B
Feb. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
13
Typical Application (Continued)
PVIN AVIN VMON
E/S
SW1
FB1
PGND
POR
SW2
FB2
L1 3.3 L2 3.3 AGND
V
IN
=3.3 to 5V
C1
10 F
C1'
1 F
V
O2
=1.2V V
O1
=2.5V
36k
4.7k
18k
30.1k
20k
C3
10 F
C2
10 F
C2'
10 F
4.02k
20k
OFF ON
Figure 21. Typical Application Circuit of AP3421A /B (Note 2)
Note 2: AVIN and PVIN pin should not be connected together directly to avoid disturbance between them in
PCB layout:
1) Place a 1.0
µF capacitor between AVIN pin and AGND for power filtering.
2) Place a 10
µF capacitor between PVIN pin and PGND for power filtering.