# MeanWell SPBW / DPBW Teardown(s)

## DPBW03F-15

DPBW03F-15 is a 3W, +/-15V isolated DCDC converter. With a wide 9-36V input, +/- 100 mA output current and 50 mV ripple, some filtering is present. In particular, the common-mode noise currents between secondary and primary sides are returned via an internal safety capacitor.
- Isolation Capacitance (typ): 500 pF, (560 pF measured, including inter-winding capacitance)
- No external safety capacitor required to pass compliance testing


### Teardown pictures

The enclosure cups are made of a chopped glass fiber reinforced plastic. The potting compound is hard but somewhat elastic when pushed with a screwdriver. When heated (hot air at 230-250°C, wear PPE), it becomes soft enough to cut and peel off surfaces.


The device is fully potted, and there are only a few air bubbles. The largest one was found between the two output capacitors on the transformer side.

#### Front Assembly

The transformer is marked "24V(D)15 V2.0 2433", which is surprisingly logical considering
- the nominal input voltage is 24V
- output is +/-15V
- they probably use the same transformer for the single and dual versions


Input and output MLCCs are integrated, no need for additional external ones (like extra 100 nF).
The black packages around the pair of MLCCs would be the output rectifier diodes immediately between the transformer pads and first pair of MLCCs.


- input capacitance: 10µF / 50V?
- output capacitances: 14.5 µF
- output capacitances are probably split into 10 µF/35V and 4.7µF/25V, see filter below
- isolation capacitance: 560 pF, probably 470 pF safety capacitor on the higher end of its tolerance range, plus transformer capacitance.


### Back Assembly


The main feedback element is a half-pitch optocoupler like Vishay VOS618A-8X001T labeled S (brand logo?) "8427 HU7 4" / "S8427"


And finally, this is what we came for in this DPBW03F-15 teardown: the output filter section (bottom-left):



The higher-voltage capacitor on the front, along with the smaller ones on the back, are connected through ferrite beads / SMD inductors. The safety cap via above the middle pin exits under the transformer where the letter (D) is seen in the pictures.

composite image:

### DPBW03F-15 summary:
- \>= 10 µF MLCC capacitance on all voltage rails, no external MLCCs needed
- single diode half-wave rectification
- LC π-filter on the outputs (another stage can be added externally without an additional pair of capacitors right around the pins)

## DPBW06F-15

With twice the power rating in a similar package, DPBW06F-15 has to omit the safety capacitor, with a larger transformer expected to take its place.

The isolation capacitance of 50 pF is likely solely attributed to the transformer itself (not great for low-capacitance applications that also have to control noise).


### Teardown

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jk I didn't buy one yet.