I am currently looking at a HMC5883L design and the datasheet has a special note for two capacitors:
The two external capacitors should be ceramic type construction with low ESR characteristics. The exact ESR values are not critical but values less than 200 milli-ohms are recommended. Reservoir capacitor C1 is nominally 4.7 Î¼F in capacitance, with the set/reset capacitor C2 nominally 0.22 Î¼F in capacitance. Low ESR characteristics may not be in
many small SMT ceramic capacitors (0402), so be prepared to up-size the capacitors to gain Low ESR characteristics.
There is also some hints that the selection really matters to get the chip working. There are some reports that tantalum caps are bad (ESR == 3R), though actual suggestions for parts are thin on the ground.
The Atmel XPLAIN board hardware notes containing the sensors it not particularly helpful as to their selection:
So, has anyone got the device working? What capacitor part numbers did you use for the critical 220nF and 4uF capacitors?