Part Review and Datasheet

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Part Review - Molex 39299166

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Date: 2026-07-21 Reviewed available part information for the Molex Mini-Fit Jr. vertical header part project, including MPN aliases, package...

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Completed the part review and updated the Datasheet URL to the direct official Molex sales drawing. I created the detailed report here: Part Review - Molex 39299166.
Open items:
  • Package/Case metadata appears wrong: TO should be cleaned up to a connector/through-hole classification.
  • Terminal pin descriptions are missing; electrically OK, but positional contact labels would improve usability.
  • Footprint dimensions match the Molex drawing within tolerance, though drill sizes are near the upper limit.
Suggested next steps:
  1. Update the incorrect Package/Case Code metadata.
  2. Add concise pin descriptions for contacts 1–16.
  3. Run a final visual footprint/3D alignment check before publishing.
Fix metadata and labels
Fix flagged issues
Check 3D alignment
Verify manufacturing readiness
Export review package
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Pin Number
14
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Pin Number
8
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Pin Number
6
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Pin Number
16
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Pin Number
15
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Pin Number
12
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Pin Number
9
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Pin Number
5
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Pin Number
7
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Pin Number
2
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Pin Number
11
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Pin Number
10
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Pin Number
13
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Pin Number
1
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Pin Number
3
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Pin Number
4

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Part Review - Molex 39299166
Date: 2026-07-21
Scope
Reviewed available part information for the Molex Mini-Fit Jr. vertical header part project, including MPN aliases, package/properties, schematic symbol terminals, footprint geometry, and pin descriptions. The official Molex datasheet/sales drawing URL was added to the part.
Datasheet Source
Current Available Part Information

Table

FieldCurrent / observed valueDatasheet / Molex referenceStatus
Project / catalog part39299166Molex page part number 39299166; aliases 39-29-9166, 0039299166OK
Library/name0039299166Material number 0039299166; part no. 39-29-9166OK
ManufacturerMolexMolexOK
DescriptionMini-Fit Jr. vertical header, 4.20 mm pitch, dual row, 16 circuits, pegs, tin, naturalMINIFIT JR VERT HDR ASSY'S W/ PEGS, 16 circuits, with pegs, natural nylonOK
Part typeConnectors / Headers and Wire HousingsPCB Headers and ReceptaclesOK
Designator prefixJ in library properties; terminals use prefix P internallyConnector use normally JOK for instantiated part; terminal internals are implementation detail
Terminal count16 terminals16 circuitsOK
Package / case codeLibrary search reported TOThrough-hole connector/header, not transistor TO packageMismatch / metadata cleanup recommended
MountPCB / through-hole footprintThrough-hole mounting and terminationOK
Datasheet URLUpdated to direct Molex drawing URLOfficial Molex drawing 55660021-SD, rev A6OK
Key Datasheet Specs

Table

SpecMolex value
ProductMini-Fit Jr. vertical header assembly with pegs
Document55660021-SD, revision A6, Production
Circuits16
Rows2
Pitch4.20 mm mating and termination interface
OrientationVertical
Termination / mountingThrough-hole
Current rating9 A max per contact
Voltage rating600 V max
Operating temperature-40 C to +105 C
Contact material / platingBrass, tin plating; 100 microinch matte tin variant
Housing materialNylon 6/6, UL 94V-0, natural
Recommended PCB thickness1.60 mm; drawing hole layout for 1.78 mm max board
PC tail length3.50 mm
Mating cycles30 max
PCB locator / retentionYes / yes, polarized to PCB
Schematic Symbol Check

Table

ItemObservedExpectedStatus
Pin count16 terminal components with Pin Numbers 1-1616 circuitsOK
Pin typeAll PassivePassive connector contactsOK
Pin numbering coveragePins 1 through 16 present once eachPins 1 through 16OK
Pin descriptionsNo Pin Description property observed on terminalsDatasheet provides generic contact/circuit positions, not signal functionsFlag: missing descriptive labels; add positional labels if desired
Symbol organizationSingle vertical list of terminalsConnector symbol can be generic or physically groupedAcceptable, but physical row grouping could improve readability
Footprint Geometry Check
Footprint asset: CONN_55660021-SD_16_MOL.kicad_mod

Table

FeatureDatasheet valueFootprint valueStatus
Signal plated drill1.40 +/- 0.05 mm1.4478 mmOK, near upper limit
Signal pad diameterNot specified in extracted drawing data1.9558 mmNot directly verifiable; annular ring approx. 0.254 mm
Column pitch4.200 +/- 0.10 mm non-accumulativeAlternates about 4.191 / 4.216 mmOK
8-column span29.4 mm nominal29.3878 mmOK
Row spacing5.50 +/- 0.10 mm5.5118 mmOK
Peg hole diameter3.00 +/- 0.05 mm3.048 mm NPTHOK, near upper limit
Right peg offset from pin column4.70 +/- 0.08 mm4.699 mmOK
Left peg offset from pin column4.70 +/- 0.08 mm4.7244 mmOK
Peg center-to-center C38.80 +/- 0.08 mm38.8112 mmOK
Peg vertical offset from terminal row0.46 +/- 0.08 mm0.4826 mmOK
Numbered copper pads16 plated through-hole pads16 plated through-hole padsOK
Mounting/locator holes2 NPTH peg holes2 NPTH peg holesOK
Pin 1 Orientation
The datasheet says circuit #1 is the lower-right signal hole when the recommended hole layout is viewed from the component side. The KiCad footprint has pad 1 at (0, 0) and pad 9 at (0, -5.5118). In KiCad/footprint convention, negative Y is visually upward, so pad 1 is the lower-right of the two rightmost signal holes. This appears consistent with the Molex drawing.
If the footprint is transformed by another importer/viewer with a flipped Y-axis, row orientation should be visually verified before release; no confirmed row-swap mismatch was found from the KiCad asset itself.
Mismatches / Issues Flagged
  1. Package or Case Code metadata appears wrong: library search reports TO, which is a transistor-style package category and does not describe this through-hole connector. Recommended value: a connector/through-hole package classification such as CONN-TH or a connector-specific package label.
  2. Pin descriptions are missing: all 16 terminals are passive and numbered correctly, but no Pin Description values are present. Since the connector contacts are generic, this is not electrically wrong; positional descriptions such as Contact 1, lower-right through Contact 16 would improve usability.
  3. Drill sizes are close to the upper datasheet tolerance: terminal drills at 1.4478 mm vs 1.40 +/- 0.05 mm and peg holes at 3.048 mm vs 3.00 +/- 0.05 mm are within tolerance but close to the maximum. Confirm the PCB fab treats these as finished hole sizes after plating where applicable.
  4. Datasheet source availability: Molex page says limited catalog information is available, but the direct official sales drawing PDF is accessible and was used for this review.
Overall Assessment
The schematic pin count and passive connector behavior match the Molex 16-circuit header. The footprint hole pattern, pitch, row spacing, peg spacing, and pin-1 orientation are consistent with the official Molex sales drawing within stated tolerances. The main cleanup items are metadata (Package or Case Code) and optional terminal pin descriptions.

  • Scope

  • Datasheet Source

  • Current Available Part Information

  • Key Datasheet Specs

  • Schematic Symbol Check

  • Footprint Geometry Check

  • Pin 1 Orientation

  • Mismatches / Issues Flagged

  • Overall Assessment

Documents

Assets

39299166

39299166

39299166.STEP3D Model

39299166

39299166 39299166 Symbol.svgDefault
0039299166-thumb.png

0039299166-thumb.png

0039299166-thumbThumbnail

39299166

CONN_55660021-SD_16_MOL.kicad_modFootprint

0039299166

0039299166 thumbnail
Connector Header Through Hole 16 position 0.165" (4.20mm)
39299166 39-29-9166
Header Connector for wire-to-board connections, featuring a vertical through-hole design with 16 male pin contacts in a 2-row configuration. It has a 4.20 mm pitch, shrouded 4-wall housing, solder termination, and is part of the Molex Mini-Fit Jr. 5566 series.
#Connector #HeaderConnector #ThroughHole #WireToBoard #Molex #MiniFitJr #5566Series

Properties

0039299166

Molex

Connectors

molex.com/content/dam/molex/molex-dot-com/products/automated/en-us/salesdrawingpdf/556/5566/039299166_sd.pdf?inline

J

PCB

parametric-v1

creativecommons.org/licenses/by/4.0/

Pricing & Availability

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