WM8321 Datasheet, PDF (248/253 Pages) Wolfson Microelectronics plc – Processor Power Management Subsystem

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.
DC3VDD
2.7V – 5.5V
DC3FB
DC3LX
L
C_IN
V_O
WM8321
DC4_SLV = 1
DC3GND
DC4VDD
DC4FB
DC4LX
C_OUT
L
C_OUT
C_IN
V_O
Load
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 47F component is recommended. For typical applications, the 22F is suitable. The alternative
values may be used for size or cost reasons if preferred.
COMPONENT
VALUE
PART NUMBER
SIZE
L
2.2H
Coilcraft LPS3015-222ML_
3 x 3 x 1.5mm
C_OUT
47F
22F
MuRata GRM21BR60G476MEA1
MuRata GRM21BR60J226ME39
0805
0805
10F
MuRata GRM188R60J106ME84
0603
CIN
4.7F
MuRata GRM188R60J475ME84
0603
Table 87 Recommended External Components - DC-DC3 / DC-DC4 Dual Mode
w
PD, February 2012, Rev 4.0
248