The symbol exposes 25 terminals (24 package pins plus the exposed ground pad). I’m now checking the part-level properties and physical pad geometry against Silicon Labs’ package data.
Audit complete. The datasheet property was already populated, so it was not changed; I verified against the official Silicon Labs datasheet.
Key flags: incorrect TO package metadata, unspecified pin types/missing descriptions, oversized exposed pad with excessive paste coverage, and inaccurate claims about configuration and battery-charger detection. The 25-terminal pin mapping is correct.
All terminal Pin Type properties are “Unspecified.” They should be classified to improve ERC:
Power input/output: VIO, VDD, VREGIN
Ground: pins 2 and 25
USB bidirectional: D+, D−
Inputs: RI, VBUS, RSTB, CTS, RXD, DSR, DCD
Outputs: SUSPENDB, SUSPEND, RTS, TXD, DTR
No-connect: pins 10–14 and 16
Pin descriptions are absent. Add the datasheet functions, including active-low behavior for RI, RSTb, CTS, RTS, DSR, DTR, DCD, and SUSPENDb.
The schematic uses RSTB/SUSPENDB; this is electrically correct, though displaying an overbar or /RST, /SUSPEND would communicate active-low semantics more clearly.
Footprint review
Current footprint asset: QFN50P400X400X80-25N-D.kicad_mod.
Correct items
4.00 × 4.00 mm package outline.
24 perimeter pads plus center pad.
0.50 mm perimeter pitch.
Perimeter pad width 0.30 mm.
Pin numbering and pad-to-terminal mapping match the symbol.
Mismatches and manufacturability concerns
Table
Feature
Datasheet land pattern
Current footprint
Assessment
Perimeter pad
0.30 × 0.85 mm
0.30 × 0.80 mm
Minor mismatch: 0.05 mm shorter than recommended.
Center exposed-pad land
2.55 × 2.55 mm
2.80 × 2.80 mm
Mismatch: 0.25 mm larger per axis than recommended and larger than the package’s 2.35–2.55 mm exposed-pad range.
Center-pad paste
2 × 2 array of 0.9 mm apertures on 1.2 mm pitch
One solid 2.80 × 2.80 mm paste opening
Significant issue: excessive paste can float the package and cause voiding/bridging.
NSMD mask clearance
Minimum 0.06 mm around pads
Not explicitly defined in imported footprint
Verify generated mask expansion before manufacturing.
Stencil thickness
0.125 mm recommended
Not represented in footprint
Manufacturing note, not a footprint defect.
The footprint’s body size, pitch, and numbering are usable, but the exposed-pad copper and especially paste geometry should be corrected before production.
Description/property mismatches
The current project description includes claims that do not match the official CP2102C-A01-GQFN24 datasheet:
“Simple GUI-based configurator” — incorrect. The datasheet explicitly states there is no support for customizing device configuration.
“USB Battery Charger Detection (USB BCS 1.2)” — incorrect for this ordering variant. The product selection table shows no Battery Charger Detect support.
“Royalty-free Virtual COM port drivers” — misleading/outdated wording. This device uses standard OS USB CDC drivers and needs no custom driver.
“Remote wakeup for waking a suspended host” — not clearly specified as a user-controlled feature. The datasheet documents USB suspend/resume behavior and says resume signaling may be detected or generated, but does not present a dedicated remote-wakeup control input/function in the feature list.
Additional integration note
The VBUS sense pin must not normally be connected directly to 5 V. Silicon Labs shows a 47.5 kΩ / 22.1 kΩ resistor divider so the pin meets both its input-high requirement and voltage limits. USB ESD protection is also recommended.
Overall result
Pin mapping: Pass.
Terminal count: Pass (24 pins + exposed pad).
Package metadata: Fail (TO must be QFN24).
Symbol electrical types/descriptions: Incomplete.
Footprint: Needs exposed-pad copper/paste correction; perimeter pads are slightly short.
Marketing description: Contains multiple inaccurate or unsupported feature claims.