- Definition
- A Power Data Object (PDO) is a single advertised power capability in USB Power Delivery, expressed as a voltage and a maximum current that the source can sustain.
This page defines the term. For what it means in practice, see USB Power Delivery and PPS: how to read a charger specification.
The idea
When a USB-C source is connected, it does not say "I am a 65 W charger". It publishes a list. Each entry on that list is a PDO, and each one names a voltage and the maximum current available at that voltage.
A device reads the list, picks the entry that suits it, and the two sides confirm the choice before power flows. If nothing on the list suits the device, it falls back to a lower capability rather than failing.
Fixed and adjustable
There are two kinds of PDO, and the distinction matters when reading a specification sheet:
Fixed PDOs name a specific voltage — 5 V, 9 V, 15 V, 20 V and, in the extended power range, 28 V, 36 V and 48 V.
Adjustable PDOs describe a voltage range the source can produce in small steps. These are what enable the fast-charging behaviours that proprietary schemes used to provide, and they are why a device can ask for a voltage that is not one of the standard fixed values.