Production Data
WM8352
When selecting a suitable output inductor, the inductance value and the saturation current must be
compatible with the operating conditions of the converter.
The magnitude of the inductor current ripple is dependant on the inductor value and can be
determined by the following equation:
As a minimum requirement, the DC current rating should be equal to the maximum load current plus
one half of the inductor current ripple:
To be suitable for the application, the chosen inductor must have a saturation current that is higher
than the peak inductor current given by the above equation. To maximise the converter efficiency,
the inductor should also have a low DC Resistance (DCR), resulting in minimum conduction losses.
Care should also be taken to ensure that the inductor is effective at the applicable operating
temperature.
Wolfson recommends the following external components for use with DC-DC Converters 1 and 6.
Note that the choice of output capacitor should be determined as described above.
COMPONENT
VALUE
2.2μH
10μF
22μF
47μF
PART NUMBER
SIZE
L
Coilcraft LPS3010-222ML (1.4A)
Murata GRM219R60J106KE19B
Murata GRM21BR60J226M
Murata GRM31CR60J476M
Murata GRM31CR60J107M
Murata GRM188R60J475KE19D
COUT
0805
0805
1206
1206
0603
100μF
4.7μF
CIN
Table 157 Recommended External Components - DC-DC1 and DC-DC6
Wolfson recommends the following external components for use with DC-DC Converters 3 and 4.
COMPONENT
VALUE
2.2μH
10μF
PART NUMBER
SIZE
1206
0805
0603
L
Murata LQM31PN2R2M00 (0.9A)
Murata GRM219R60J106KE19B
Murata GRM188R60J475KE19D
COUT
CIN
4.7μF
Table 158 Recommended External Components - DC-DC3 and DC-DC4
PD, February 2011, Rev 4.4
327
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
