WM8321
Production Data
30.3.1 DC-DC3 / DC-DC4 DUAL MODE
When DC-DC3 and DC-DC4 are operating in dual mode, the external component configuration for
each converter is the same as previously noted for single converters. The output load connection
points (Vo) are simply connected together as shown in Figure 30.
2.7V – 5.5V
DC3VDD
DC3FB
CIN
L
DC3LX
VO
COUT
DC3GND
WM8321
DC4VDD
DC4FB
DC4_SLV = 1
CIN
L
DC4LX
VO
Load
COUT
DC4GND
Figure 30 DC-DC3 / DC-DC4 Dual Mode Converter Connections
Wolfson recommends the following external components for use with DC-DC Converters 3 and 4
when operating in Dual Mode.
The output capacitor must be consistent with the DCm_CAP register setting. For best performance,
the 47F component is recommended. For typical applications, the 22F is suitable. The alternative
values may be used for size or cost reasons if preferred.
COMPONENT
VALUE
2.2H
47F
PART NUMBER
SIZE
3 x 3 x 1.5mm
0805
L
Coilcraft LPS3015-222ML_
COUT
MuRata GRM21BR60G476MEA1
MuRata GRM21BR60J226ME39
MuRata GRM188R60J106ME84
MuRata GRM188R60J475ME84
22F
0805
10F
0603
CIN
4.7F
0603
Table 87 Recommended External Components - DC-DC3 / DC-DC4 Dual Mode
PD, February 2012, Rev 4.0
248
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
