Design Log DEC 006 stusb4500 negotiates 15v5a 75w - thepinkmile/Enigma-NG GitHub Wiki

DEC-006 - STUSB4500 Negotiates 15V/5A (75W)

• Status: Decided
• Date: 2025
• Category: Electrical
• Area: Power Module USB-C PD handshake (STUSB4500), USB-C adapter requirement

Decision

The STUSB4500 standalone PD sink is programmed to negotiate 15V/5A (75W) from the wall adapter or USB-C PD source. Earlier documentation incorrectly stated 15V/3A.

Rationale

• 3A (45W) is insufficient for worst-case system load (CM5 at 25W + rotors + supercap charging).
• 5A (75W) provides headroom and aligns with the 75% derating target at the eFuse.
• Users must use a USB-C PD adapter rated for at least 75W (15V/5A or 20V/5A with appropriate negotiation cap).