The USB Implementers Forum raised max USB voltage from 5.25V to 5.50V, retroactively.
I took this personally. They got away with literally raising the maximum voltage of the USB port. With billions of devices in the field. Those devices were designed to receive 5.25V maximum. And now they can receive 5.5V from a new port.
In manufacturing, my deviation requests used to get denied all the time. So many hours getting everyone in the plant to agree, so many hours writing good arguments on the request forms... Most of the time, if they got denied it was for good reason. But I still had to request them to make management happy.
I have to laugh because the other option is to cry
USB ENGINEERING CHANGE NOTICE
Title: USB 2.0 VBUS Max Limit
Applies to: Universal Serial Bus Specification, Revision 2.0Summary of ECNUpdate the USB2.0 specification to align with the expanded VBUS voltage definition in the USB-IF Type-C
specification which defines VBUS as having a Max supply voltage of 5.50 V DC.
The Type-C cable and connector definition specifies a minimal current carrying capacity of 3A. This increased
capacity creates a situation where losses in cables, connectors, PCB traces and power supply components will result
in the VBUS level available at the consumer end of the cable that is below the minimum acceptable level for
operation. As a result, in order to have an implementable Type-C specification it is necessary to boost the upper limit
for VBUS at the supply side to 5.5V DC from the present spec value of 5.25 V DC.
Reasons for ECN
OEM’s can design products that support the higher power levels of the Type-C connector and provide VBUS levels at
or above 5.25V to ensure that the VBUS voltage that is available at the far-side connection is within a suitable working
range for USB products, and is also at a high enough level to charge batteries in as short a time interval as possible to
ensure customer satisfaction.
Impact on Existing Peripherals and Systems:The impact is difficult to assess
[you don't say!? ] as there is a wide range of component vendors supporting USB, and also a wide
variation of design methodologies.
As a result, there are certainly going to be a subset of existing USB products that may be sensitive to operation at
VBUS levels of up to 5.5V. The sensitivity will be mitigated in many cases by cable losses, so the devices themselves
may never experience the 5.5V.
Hardware Implications:
New designs adhering to this ECN will need to consider the new 5.5V VBUS max level during the component
selection process.
Software Implications:
There are no known software implications.
Compliance Testing Implications:
Compliance will need to make the small modifications necessary to accommodate the new upper limit.
Emphasis added by myself.
Note: if anyone at the USB-IF is reading, I imagine this was not an easy decision. It's just funny how all this strict compliance is thrown out the window when the approvers are also affected and there are no other realistic solutions.