WM8321 datasheet(92/253 Pages) WOLFSON

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WM8321

Production Data

PD, February 2012, Rev 4.0

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.

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