The KED601H is a plastic-molded visible-light (infrared) LED emitter manufactured by Kyoto Semiconductor, designed for through-hole mounting in a radial package with an 890 nm peak wavelength. This component sits within the LED Emitters - Infrared, UV, Visible category of optoelectronics, serving applications in industrial sensing, optical encoders, and proximity detection. Procurement specialists face real risks from counterfeit, refurbished, or mislabeled units that may deliver incorrect wavelength, degraded output power, or insufficient thermal tolerance. The following verification framework covers visual inspection, parameter measurement, package analysis, and sampling protocols specific to the KED601H.

Visual and Marking Inspection: Laser Etch versus Ink Print Decoding

Genuine Kyoto Semiconductor KED601H units carry a laser-etched marking on the epoxy body. Laser etching produces a shallow, uniform, non-smearing imprint that resists solvent wipe tests. Counterfeit parts often use ink printing, which shows uneven edges, pooling, or smudging under 10x magnification. Inspect the marking under a stereomicroscope at 20x–40x magnification. The authentic marking includes the part number (KED601H) and a four-digit date code in YYWW format (year and work week, e.g., 2437 for week 37 of 2024). The date code must align with the production window stated on the Certificate of Conformance (COA). Decode the lot number, cross-referencing it against Kyoto Semiconductor's issued lot traceability documentation. Reject any unit where the marking appears lifted, has jagged charring, or differs in font from the manufacturer's published marking specification. Additionally, measure the epoxy body dimensions with digital calipers: the radial package has a standard 5 mm diameter lens, a 4.5 mm body height, and 2.54 mm pin pitch. Deviations greater than 0.2 mm in any dimension indicate a likely non-genuine part.

Electrical and Optical Parameter Measurement Methods

Procurement must validate the key parameters listed in the supplier-must-confirm checklist below. For the KED601H, the critical pass/fail criteria are:

• Forward Voltage (Vf): Use a Keithley 2400 SourceMeter or equivalent in pulsed mode (pulse width 1 ms, duty cycle <0.1%) to avoid self-heating. Apply an IF of 20 mA (typical test current) and measure Vf. The typical value is 1.5 V, with a legitimate range of 1.2 V to 1.8 V at 20 mA. Units showing Vf below 1.0 V or above 2.0 V at this current are suspicious.
• Radiant Intensity / Output Power: Use a calibrated integrating sphere (e.g., Labsphere) with a silicon photodiode detector. Set IF = 100 mA (maximum rated current) and measure the radiant power in mW. The KED601H typical output at 100 mA is 12 mW. Acceptable tolerance is ±30% per Kyoto Semiconductor's binning guidelines. A reading below 6 mW indicates a degraded or counterfeit emitter.
• Peak Wavelength: Use a spectrometer (e.g., Ocean Insight Flame) with 1 nm resolution. The KED601H emits at 890 nm with a spectral half-width of 40 nm. Acceptable range is 880 nm to 900 nm. Wavelength outside this range will shift the responsivity curve of paired photodetectors.
• Viewing Angle: Measure the full width at half maximum (FWHM) using a goniometer setup. The spec is 28°. Acceptable range is 24° to 32°. Narrower angles reduce coverage in sensor arrays; wider angles dilute irradiance.

A sampling of 20 units from each production lot should be tested. Reject the lot if more than one unit fails any parameter beyond the listed tolerance.

X-Ray Inspection and Decapsulation for High-Value Applications

For applications in medical equipment, automotive LiDAR, or industrial safety systems where field failure is unacceptable, perform X-ray inspection on a sample of units. Use a microfocus X-ray system at 60–80 kV. The KED601H die is a square GaAs chip approximately 0.35 mm × 0.35 mm, bonded to the lead frame with silver epoxy. The X-ray image must show:

• A centered die with no visible cracks or voids larger than 5% of the bond area
• A single 25 μm gold wire bond from the die top to the anode lead
• No solder bridging or foreign particles in the epoxy body

If X-ray reveals inconsistent die placement or multiple wire bonds (indicating a reworked or different die), the unit is counterfeit. For ultra-high-reliability verification, perform chemical decapsulation on one sample per lot using hot nitric acid (80% HNO? at 80°C, 2–3 minutes). Examine the die surface under a scanning electron microscope (SEM). Authentic Kyoto Semiconductor dies carry a proprietary alphanumeric die code laser-marked at the corner. Absence of this code, or presence of grind marks from removal from another package, indicates a refurbished or scavenged part.

Packaging, COA Cross-Check, and AQL Sampling Plan

Genuine KED601H units ship in antistatic tubes or tape-and-reel packaging with a Kyoto Semiconductor label that includes the part number, date code, quantity, and a 2D barcode. Match the date code on the label to the marking on the first and last unit in the tube. The COA must state the measured Vf and radiant intensity at IF = 20 mA for the specific lot, plus the storage temperature range (-40°C to 125°C). Use Attribute Sampling Plan AQL 0.65 (Major Defects) per ANSI/ASQ Z1.4-2008. For a lot of 1000 units, sample size is 80 units. Accept zero units with marking defects, wavelength errors >10 nm, or Vf outside the datasheet range. Accept up to two units with cosmetic blemishes (scratches on epoxy) if the parameter measurements pass.

The two most critical specs are the 100 mA maximum forward current and the 890 nm wavelength. The current limit, combined with a 1.5 V typical Vf, means the junction temperature rises approximately 0.8°C per 10 mA of continuous current. For applications requiring continuous operation at 100 mA, ensure the ambient temperature stays below 85°C; otherwise, derate to 70 mA. The 890 nm wavelength is not visible to the human eye, which is advantageous for daylight-sensing systems but requires absolute alignment with the detector's spectral response curve. A shift of just 10 nm toward 900 nm drops silicon photodiode responsivity by roughly 15%, so verify the wavelength of every incoming lot with a spectrometer, not a simple photometer.

Procurement Workflow Summary

Adopt the following step-by-step verification for every KED601H lot: (1) Confirm COA lot number matches tube/tape labels. (2) Perform visual inspection on 20 units per 1000-unit lot using 20x magnification, checking marking quality and body dimensions. (3) Measure Vf and radiant intensity on 20 units at IF=20 mA and IF=100 mA respectively, using a pulsed source. (4) For safety-critical orders, conduct X-ray inspection on 5 units and chemical decapsulation on 1 unit. (5) Apply AQL 0.65 sampling; reject the lot if more than 2% of units fail any specification. Document all results in a lot-specific test report. This workflow minimizes the risk of field failures, warranty returns, and production line stoppages.