I’ll audit the part metadata, locate and attach the official Holtek datasheet if needed, then verify the symbol pins and 28-pin SOP footprint against it. I’ll record the detailed findings in a project review file and summarize any mismatches here.
The symbol has all 28 terminals, but every terminal currently has an unspecified pin type and no pin description. I’m now checking the package geometry and authoritative pin table to distinguish metadata gaps from true pinout or footprint errors.
Audit of project metadata, 28-terminal schematic symbol, SOP-28 footprint, pad mapping, pin naming, and pin descriptions for the Holtek HT16K33 LED controller/driver.
Document identity used for comparison: HT16K33, revision V1.10.
The part's Datasheet property was populated during this review. Flux stored the retrieved PDF as a project-hosted asset.
Verification note: Holtek now promotes the later HT16K33A revision on its current product page. The legacy HT16K33 pinout was specifically checked because this project is named for the non-A device.
Audit complete. I attached the official Holtek datasheet and confirmed the 28-pin symbol pinout, pad mapping, 1.27 mm pitch, and SOP-28 mechanical envelope are consistent.
Key issues:
Package property incorrectly says 16-SOP; it should be 28-pin SOP, 300 mil.
All pins have unspecified electrical types and lack descriptions.
HT16K33-28SOP may not be the exact manufacturer ordering code.
Holtek now promotes the HT16K33A; interchangeability and lifecycle require confirmation.
Audit of project metadata, 28-terminal schematic symbol, SOP-28 footprint, pad mapping, pin naming, and pin descriptions for the Holtek HT16K33 LED controller/driver.
Document identity used for comparison: HT16K33, revision V1.10.
The part's Datasheet property was populated during this review. Flux stored the retrieved PDF as a project-hosted asset.
Verification note: Holtek now promotes the later HT16K33A revision on its current product page. The legacy HT16K33 pinout was specifically checked because this project is named for the non-A device.
Existing Part Information
Table
Field
Existing value
Review
Project/part name
HT16K33-28SOP
Descriptive package-qualified name; the datasheet device marking is HT16K33.
Manufacturer
Holtek
Correct.
MPN
HT16K33-28SOP
Package-qualified catalog-style identifier; not shown as the base device number in the datasheet. Confirm purchasing order code before release.
Part type
Optoelectronic Devices
Broad but usable; “LED controller/driver” would be more precise.
Package/case property
16-SOP
Incorrect: the device, symbol, and footprint have 28 pins. This should identify a 28-pin SOP, 300 mil package.
Pin/pad count
28
Correct.
Footprint asset
SOIC127P1031X264-28N.kicad_mod
Consistent with 1.27 mm pitch and a 28-lead wide SOP/SOIC body.
3D model
HT16K33-28SOP.stp
Present; dimensional alignment was not independently measured from the mesh.
Description
Key-in LED control driver RAM I2C, 28 SOP; 16-segment, 5 V
Functionally consistent, though “16 segments × 8 commons” and “4.5–5.5 V” would be more exact.
Key Specifications
Supply operating range: 4.5 V to 5.5 V; 5 V nominal.
Operating temperature: -40 °C to +85 °C.
Absolute maximum supply: VSS - 0.3 V to VSS + 6.5 V.
Display capacity: up to 16 segments × 8 commons, 128 LED patterns.
Display RAM: 16 × 8 bits.
Key scan: up to 13 × 3 matrix.
Brightness control: 16 steps.
Interface: bidirectional I²C, up to 400 kHz.
Address range: 7-bit 0x70 through 0x77 using A2:A0.
Integrated RC oscillator.
Package under review: 28-pin SOP, 300 mil, 1.27 mm lead pitch.
Pinout Cross-check
The symbol and pad mapping match the legacy HT16K33 28-pin SOP pin assignment exactly:
Table
Pin
Symbol/pad name
Datasheet result
1
VSS
Match
2
COM0/AD
Match
3
COM1/KS0
Match
4
COM2/KS1
Match
5
COM3/KS2
Match
6
COM4
Match
7
COM5
Match
8
COM6
Match
9
COM7
Match
10
ROW15/K13/INT
Match
11
ROW14/K12
Match
12
ROW13/K11
Match
13
ROW12/K10
Match
14
ROW11/K9
Match
15
ROW10/K8
Match
16
ROW9/K7
Match
17
ROW8/K6
Match
18
ROW7/K5
Match
19
ROW6/K4
Match
20
ROW5/K3
Match
21
ROW4/K2
Match
22
ROW3/K1
Match
23
ROW2/A0
Match
24
ROW1/A1
Match
25
ROW0/A2
Match
26
SCL
Match
27
SDA
Match
28
VDD
Match
Pin Description and Electrical-Type Review
All 28 terminals currently have Pin Type: Unspecified and no populated pin-description property. This is the largest symbol-quality gap. Recommended classifications:
VDD: power input — positive logic supply.
VSS: power input/ground — logic ground.
SDA: bidirectional/open-drain I/O — I²C serial data.
SCL: input — I²C serial clock.
COM0/AD: output/multiplexed — active-low common output; address source during reset/key scan.
COM1/KS0 through COM3/KS2: output/multiplexed — active-low common outputs; key-scan source outputs.
COM4 through COM7: outputs — active-low common outputs.
ROW0/A2 through ROW2/A0: bidirectional/multiplexed — active-high row outputs; address inputs with internal pull-down during reset/key scan.
ROW3/K1 through ROW14/K12: bidirectional/multiplexed — active-high row outputs; key-data inputs with internal pull-down during key scan.
ROW15/K13/INT: bidirectional/multiplexed — row output/key input or programmable interrupt output.
Footprint Cross-check
Pad count: 28 — correct.
Numbering orientation: correct counter-clockwise SOP convention, with a visible pin-1 marker.
Pitch: 1.27 mm — matches the datasheet.
Modeled body: approximately 17.904 mm long × 7.06 mm wide — within the datasheet envelope of 17.70–18.11 mm length and 6.50–7.62 mm body width.
Pad center row spacing: 9.30 mm; pad length: 2.10 mm. This is a plausible land pattern for the 9.98–10.64 mm overall lead span and provides toe/heel allowance.
No exposed pad is required or present.
No footprint pin-number or gross package-dimension mismatch was found. The exact land-pattern recommendation is not explicitly dimensioned in the legacy IC datasheet, so final paste/mask and toe/heel geometry should be checked against the intended assembler's SOP-28/300 mil standard before manufacturing release.
Flagged Mismatches and Risks
Definite metadata error — package/case is 16-SOP. The correct package is 28-pin SOP, 300 mil.
Symbol metadata incomplete — every pin type is unspecified. This weakens ERC and can hide invalid electrical connections.
Symbol documentation incomplete — no pin descriptions are populated. Multiplexed address, key-scan, common, row, and interrupt behavior should be documented.
MPN ambiguity — HT16K33-28SOP is package-qualified, while the legacy datasheet identifies the device as HT16K33. Confirm the exact orderable suffix used by the intended supplier.
Revision/lifecycle risk — Holtek's current page promotes HT16K33A and lists it under EOL Expired. Do not assume the A revision is interchangeable without a separate change-control review, despite the matching 28-pin assignment shown in current documentation.
**Description precision — “5 V” is directionally correct but should state 4.5–5.5 V; “16-segment” should state 16 segments × 8 commons.
Overall Result
The electrical pin names, pin numbers, pad mapping, pitch, and basic SOP-28 mechanical envelope are consistent with the legacy HT16K33 datasheet. The part is structurally usable, but its package metadata and terminal electrical metadata should be corrected before relying on it for library-quality reuse or ERC-driven design review.