FAQ
TL;DR: Forum sleuthing points to a unidirectional TVS diode; one user “turned up eight manufacturers” sharing LE/LP SMD codes. “Turned up eight manufacturers.” [Elektroda, Tom Blough, post #21660206]
Why it matters: This FAQ helps you identify mystery SMD diodes/TVS parts, decode markings, and avoid polarity and replacement mistakes—fast.
Quick Facts
- LE code maps to Approx. 12 V breakdown TVS; LP maps to Approx. 16 V breakdown TVS. [Elektroda, Tom Blough, post #21660206]
- A printed line can indicate diode cathode, but verify with a meter to avoid reversal errors. [Elektroda, Steve Lawson, post #21660209]
- Date codes like “948” often mean year-week format (YYW or YWW). [Elektroda, Pieter Kruger, post #21660205]
- IV tracing lets you measure knee voltage and polarity to match a replacement. [Elektroda, Joe Wolin, post #21660204]
- Suspected logo match to Diodes Inc exists in a datasheet illustration. [Elektroda, Todd Hayden, post #21660214]
What is this part most likely?
It’s most likely a unidirectional TVS diode in an SMD package. The LE and LP top marks align with 12 V and 16 V breakdown parts. The stripe suggests the cathode orientation in typical TVS/diode markings. Use a meter or IV tracer to confirm before replacement. [Elektroda, Tom Blough, post #21660206]
What do the SMD codes “LE” and “LP” mean on this device?
In this thread, LE corresponded to an Approx. 12 V breakdown unidirectional TVS diode, and LP to an Approx. 16 V version. These codes appear across multiple vendors, so verify electrically and by package outline before substituting. “Turned up eight manufacturers” using the same codes, so cross-check datasheets. [Elektroda, Tom Blough, post #21660206]
Does the stripe always mark the cathode?
Do not assume it always marks the cathode. One engineer reported parts where the stripe marked the anode, leading to reversed installs. Confirm with a multimeter’s diode test: forward direction should show a junction drop; reverse should read open. “They had neglected to try reversing their probes.” [Elektroda, Steve Lawson, post #21660209]
How can I tell if the logo is Diodes Inc?
Compare the printed logo against a known Diodes Inc logo shown in a related datasheet image. If the graphic styling matches, you may have a Diodes Inc device or an older/cross-marked variant. Always verify with electrical tests and package dimensions before ordering replacements. [Elektroda, Todd Hayden, post #21660214]
Did Diodes Inc confirm the part as theirs?
A user contacted Diodes Inc and reported the company said it wasn’t theirs. That can happen with legacy marks, private labels, or counterfeits. Proceed by validating function and ratings rather than relying solely on the logo. Keep notes for future cross-referencing. [Elektroda, Nauman Chughtai, post #21660212]
What does a mark like “948” mean on the package?
It’s a date/lot code. In this context, “948” was interpreted as manufacturing year and week (YWW/YYW). Use it to estimate device age and to track batches in repairs. Combine with the top code and package to narrow datasheet searches. [Elektroda, Pieter Kruger, post #21660205]
How do I characterize an unknown TVS/diode quickly?
Use this 3‑step check: 1. Inspect top code, logo, and stripe. 2. Measure with a multimeter and, if available, an IV tracer to see knee voltage and polarity. 3. Compare results with candidate datasheets by code and package. This triangulates function and safe substitutes. [Elektroda, Joe Wolin, post #21660204]
Do the circuit measurements support it being a TVS?
Yes. The lamp module measured 16 VDC without load and 9.4–9.6 VDC with three white LEDs, matching a constant-current driver and a clamp device nearby. That behavior aligns with a protective unidirectional TVS across the LED string. The data narrows viable breakdown ratings. [Elektroda, Tom Blough, post #21660206]
Could this TVS fail if an LED opens?
Yes. If an LED in the string goes open, the driver may raise voltage and the TVS can conduct hard, overheating and failing. Placement and upstream limits decide survivability. “I am concerned that the TVS will be destroyed if any of the LEDs go open circuit.” [Elektroda, Pieter Kruger, post #21660207]
How do I test diode polarity with a multimeter?
Use the diode-test mode. Touch red to anode and black to cathode to read a forward drop. Reverse the probes; it should read open. If it reads the opposite, the stripe may mark anode on that family. Always verify both directions before committing. [Elektroda, Steve Lawson, post #21660209]
Where can I search unknown logos and SMD codes?
Check curated logo and code indexes such as the integrated-circuit logos archives and SMD code lists. Cross-match the graphic, then validate by electrical tests and package dimensions. Keep screenshots of close matches to build your own lookup library. [Elektroda, Steve Lawson, post #21660213]
What is a TVS diode in plain terms?
A TVS (transient-voltage-suppressor) diode clamps voltage spikes to protect circuits. Unidirectional TVS parts resemble diodes and have a breakdown rating, such as Approx. 12 V (LE) or 16 V (LP). They conduct briefly during surges, then return to high impedance. [Elektroda, Tom Blough, post #21660206]
What is an IV tracer and why use it here?
An IV tracer plots current versus voltage. It reveals forward direction, knee voltage, and clamping behavior. For unknown diodes/TVS parts, it quickly distinguishes zeners/TVS from rectifiers and helps pick a safe substitute part number and rating. [Elektroda, Joe Wolin, post #21660204]
