WM8321
Production Data
Typical Connections
The typical connections to DC-DC Converter 1 are illustrated in Figure 20. The equivalent circuit
applies to DC-DC Converters 2, 3 and 4 also.
The input voltage connection to DC-DC Converters 1-4 is provided on DC1VDD, DC2VDD, DC3VDD
and DC3VDD respectively; these pins must be connected to the PVDD power supply voltage node.
Figure 20 DC-DC Synchonous Buck Converter Connections
The recommended output capacitor COUT varies according to the required transient response. Note
that the DCm_CAP register field must be set according to the output capacitance on each DC-DC
Converter in order to achieve best performance.
In the case of DC-DC1 and DC-DC2, the recommended inductor component varies according to the
DCm_FREQ register field. This register allows a choice of different switching frequencies and
inductor components.
See Section 30.3 for details of specific recommended external components.
DC-DC3 / DC-DC4 Dual Mode
DC-DC Converters 3 and 4 can be configured to operate in ‘Dual’ mode, where the two converters are
ganged together to support an increased current capability. This mode is selected by setting the
DC4_SLV bit in the OTP/ICE memory configuration registers.
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 21.
PD, February 2012, Rev 4.0
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
