Quick answers on this page
- Are Molex connectors still used?
- What is a connector?
- What is a Molex 50058?
- Why do I keep seeing Molex in power supply and LLC circuits?
- Which Molex connector should I choose?
- When should I not use a Molex connector?
- Where should I buy Molex connectors?
Are Molex connectors still used?
Yes, but let's get more specific because 'Molex' isn't one connector. It's a brand, and its catalog covers everything from tiny wire-to-board signal connectors to high-current interconnects for cars, medical gear, and power supplies. The old 4-pin PC power connector is what most people remember, but that's a tiny slice of the picture.
In my role coordinating rush component orders, I see Molex part numbers on a weekly basis. Last quarter alone, we processed 47 rush orders for connectors, and 43 of them were for current-generation Molex systems - not legacy parts. Also, the brand is still investing: Molex, now part of Koch Industries, keeps releasing new connector families rather than just supporting old ones. Bottom line: yes, Molex connectors are still used every day in new designs. They're just not all the same shape as the one from your 1998 desktop.
What is a connector?
A connector is the part that makes an electrical circuit separable. It lets you join two assemblies without soldering them permanently together. A typical connector has a plastic housing, metal terminals, and some kind of locking or strain-relief feature.
When an engineer asks about 'what is a connector?', they're usually asking a deeper question: what does it need to do here? And the answer is always the same: carry current or signals clearly, hold mechanically, and survive whatever environment it's in. If a connector is underrated for current or doesn't latch correctly, the whole product can fail. That's why connector selection isn't an afterthought.
What is a Molex 50058?
Molex 50058 is a base part number, not a single exact product. In Molex's numbering system, the full part number carries the details. For example, a drawing might list something like 50058-XXXX, where the suffix defines the number of circuits, keying, orientation, and packaging.
The reason this matters is practical. I've watched rush orders fail because someone assumed 'a 50058' was one size fits all. It isn't. You have to line up the exact datasheet for the full part number and check the terminal system. If you're looking at a power supply BOM, don't write 'Molex 50058' on the purchase order and hope for the best.
Why do I keep seeing Molex in power supply and LLC circuits?
Because power supplies are reliability-critical, and a connector with a known datasheet beats a random 'compatible' part every time. In an LLC resonant power supply, you have high-frequency switching, tight board layouts, and real amounts of current moving through the input and output paths. That's not the place to guess. Just to clear up one confusing search term: in this context, LLC usually means LLC resonant converter, not a company type.
This doesn't mean every Molex part is right for every PSU. It means that when an engineer picks a Molex connector, they're buying a documented current rating, a controlled keying scheme, and a global supply chain. From fan headers to main output connectors, you'll see Molex parts used where 'it fits' isn't good enough.
Which Molex connector should I choose?
There's no universal 'best' Molex connector. The right one depends on current, voltage, wire gauge, temperature, vibration, and how many plug-unplug cycles it needs to survive. A signal connector that's perfect for a control board might melt in a 30A output path.
If you're in that situation, start from the datasheet, not the brand. According to Molex's published engineering specifications, current rating data is tied to the exact part number and terminal system, not to the brand name. And never pick by the photo on a reseller's site. I recommend Molex for new builds when you need qualified performance and the part is available through authorized distributors. But if you're building a one-off prototype with no mechanical stress, sometimes a generic connector is enough. Be honest about the environment.
When should I not use a Molex connector?
Here's a conversation nobody wants to have in a quarterly review: a cheaper connector failed in the field. That's the reason I default to qualified parts for high-reliability work. But I also know there are cases where Molex is overkill: disposable products, non-repairable consumer boards, or early prototypes where the design may change next week.
In March 2024, I had to decide in 24 hours whether to approve a 'direct replacement' for a 50058-series part. Normally, I'd run a full qualification, but there was no time. In hindsight, I should have caught the terminal pull-force difference earlier. We paid an extra $700 in overtime and recertification because the first replacement didn't meet spec. That's when I learned: 'compatible' is not the same as 'qualified.'
Where should I buy Molex connectors?
Buy from authorized distributors or directly through Molex. For North America, that includes major distributors like Digi-Key, Mouser, Newark, and Arrow. For other regions, check Molex's distributor page.
If a deal looks too good to be true, check the date codes, lot numbers, and packaging. Counterfeit connectors exist, and they don't always fail right away; they fail after thermal cycling or vibration. When we build to IPC/WHMA-A-620, we verify terminal crimps and pull-off forces. The connector you buy is the cheapest part of the lesson until it becomes the most expensive one.
