MRK112-A Part Datasheet Audit
Sources
The Datasheet URL property was already populated, so it was not changed. The existing URL is an official NKK product page; the direct official catalog PDF above contains the dimensional drawings and detailed specifications used for this audit.
Part Identity and Key Specifications
- Series/type: MR Series, half-inch diameter process-sealed rotary switch
- Circuit: SP12T, one common and twelve selectable contacts
- Adjustable positions: 2 through 12
- Contact timing: non-shorting / break-before-make
- Indexing angle: 30 degrees
- Actuator option: plain black knob (-A)
- Mounting: panel mount with straight through-hole PC terminals
- Terminal count: 13 electrical terminals (A common plus terminals 1 through 12)
- Rating: 0.4 VA maximum at 28 V AC/DC maximum, resistive load
- Applicable range: 0.1 mA to 0.1 A at 20 mV to 28 V
- Contact resistance: 50 milliohms maximum
- Insulation resistance: 100 megohms minimum at 500 VDC
- Dielectric strength: 500 VAC minimum for 1 minute
- Mechanical life: 30,000 operations minimum
- Electrical life: 10,000 operations minimum
- Operating temperature: -10 to +70 degrees C
- Environmental sealing: IP67 for MRK
- Body diameter: 16.0 mm
- Bushing: M6 x 0.75
- PCB terminal circle: 12.0 mm diameter
- Recommended PCB hole diameter: 0.8 mm typical
- Terminal angular spacing: 30 degrees typical
Metadata Review
Correct
- Manufacturer Part Number: MRK112-A
- Manufacturer Name: NKK Switches
- Designator prefix: S is appropriate for a switch
- Project description generally identifies a low-profile 2-12-position rotary switch
- Total pad/terminal count is 13
Incomplete or Ambiguous
- The description does not state SP12T, non-shorting, 0.4 VA at 28 V, through-hole PC terminals, panel mounting requirement, or IP67.
- No package/case property is present. A useful package description would be panel-mount, through-hole PC terminals, 16 mm body, 12 mm terminal circle.
- The Datasheet URL is an official product page rather than the direct official catalog PDF. It is valid, but the PDF is more useful for model verification.
Schematic Symbol Cross-Check
Required datasheet terminal naming
- Common terminal: A
- Selectable terminals: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
- All switch contacts should normally be electrical type Passive.
Mismatches found
- Common is numbered
A1; the datasheet identifies it as A.
- Pin 1 is named
NC, incorrectly implying no-connect or normally-closed. It is selectable contact 1.
- Pins 2 through 11 are named
NO_1 through NO_10, shifted by one and incorrectly described as normally-open relay-style contacts. They should be named 2 through 11 (or POS_2 through POS_11 while preserving pin numbers).
- Pin 12 is named
B6, which is unrelated to the MRK112-A datasheet. It should be contact 12.
- Every pin has unspecified electrical type; Passive is appropriate.
- Pin descriptions are absent. Suggested descriptions:
Rotary common contact for A and Selectable rotary contact N for each numbered terminal.
- The current symbol does not clearly depict a rotary SP12T switching relationship; it appears as a set of generic terminal objects.
Footprint Cross-Check
Datasheet requirements
- 13 through-hole terminals: A and 1-12
- Numbered contacts arranged at 30-degree increments on a 12.0 mm diameter terminal circle
- 0.8 mm diameter PCB holes typical
- Orientation must follow the manufacturer bottom-view/PCB layout drawing.
Mismatches found
- Pad naming inherits the symbol errors:
NC, NO_1 through NO_10, B6, and COM instead of A and 1-12.
- Several pad positions are not on the required 12.0 mm terminal circle. In particular, footprint pads 1, 2, and 3 are placed close to the center at approximately 1.57 mm, 3.11 mm, and 4.59 mm radius instead of 6.0 mm radius.
- The common pad is centered, which is plausible, but is designated
A1 rather than A.
- Pad 6 uses a 0.75 mm drill and 1.2 mm copper diameter, while the catalog specifies 0.8 mm holes typical and the other pads use 0.8 mm drills. This inconsistency is not supported by the datasheet information reviewed.
- The footprint courtyard/body representation extends asymmetrically and should be rechecked against the official mechanical drawing and orientation datum.
- Because the copper pad locations do not match the manufacturer terminal pattern, the footprint should be considered unsafe for fabrication until corrected.
Overall Assessment
Status: Major mismatch / not production-ready. The identity and total terminal count are correct, but the symbol pin naming and descriptions are substantially incorrect, and the footprint has multiple terminal locations that do not match the required 12 mm circular pattern. Correct the symbol and rebuild/verify the footprint from the official NKK drawing before using this part on a PCB.