A Procurement Manager’s 5-Step Checklist for Evaluating Kemet Capacitors and Connectors

Who This Checklist Is For

If you’re sourcing Kemet capacitors – especially the T491 tantalum series – or any connector for your next production run, you’ve probably already noticed that prices vary wildly. Maybe you’re a procurement manager under pressure to cut costs. Or an engineer who got burned last quarter because a “cheaper” substitute didn’t match specs. This checklist is for you. I’m a procurement manager who’s tracked over $180,000 in component spending across six years, and I’ve made enough mistakes to know what actually matters when evaluating Kemet Company parts (and their distributors).

Here are the five steps I follow every time. They won’t make you an expert overnight, but they will keep you from repeating my worst blunders.

Step 1: Verify Specifications, Don’t Assume “Equivalent” Means the Same

The mistake I made: I assumed “same specifications” meant identical performance across vendors. Didn’t verify. Turned out each distributor had slightly different interpretations of “high‑reliability.” The result? A batch of Kemet T491 capacitors that looked okay on paper but failed under ripple current – we lost a week of production.

What to do instead: Pull the actual datasheet from Kemet’s official site (kemet.com). Cross‑check at least these three parameters:

• Voltage rating (derate it properly – 50% for tantalum is my rule of thumb)
• ESR (equivalent series resistance – T491 datasheets list it at 100kHz)
• Temperature range (don’t just look at the “‑55°C to +125°C” blanket spec)

Don’t rely on a distributor’s summary table. One supplier might list a 10µF/16V tantalum as “T491A106M016AT,” but that “A” case size might have a different ESR than the “B” case you actually need. Verify every character. The 5 minutes you spend checking datasheet cross‑references can save you a 5‑day rework cycle.

Step 2: Calculate Total Cost of Ownership – Not Just Unit Price

Most buyers focus on per‑unit pricing and completely miss setup fees, revision costs, shipping, and packaging that can add 30–50% to the total. That’s the classic outsider blindspot. I learned it the hard way when I compared two quotes for a connector order: Vendor A quoted $0.42/unit, Vendor B quoted $0.38. I almost went with B until I calculated TCO: B charged $150 for ESD‑safe packaging, $85 for documentation, and a “minimum release fee” of $200. Vendor A’s $0.42 included all of that. Bottom line? Vendor B’s “cheaper” parts would’ve cost us 18% more in real terms.

Your TCO checklist for any Kemet order:

• Component price – obviously
• Packaging & handling – are your parts in tape‑and‑reel, cut tape, or bulk? Each costs differently, and some reels are non‑refundable.
• Minimum order quantities (MOQ) – a $0.10 capacitor is meaningless if you have to buy 5,000 of them.
• Hidden fees – expedited shipping, customs brokerage (for global distributors), and “quality assurance” surcharges.
• Obsolescence risk – is that Kemet 3310 series connector being phased out? A “cheaper” obsolete part means you’ll pay for last‑time‑buy or redesign later.

Step 3: Confirm Authorized Distribution and Traceability

I said “I need Kemet T491 capacitors.” They heard “any tantalum that fits the footprint.” We were using the same words but meaning different things. Discovered this when the order arrived and nothing matched our inspection criteria. The parts were from a broker, not an authorized Kemet distributor. Traceability was a joke.

Don’t assume a seller listing “Kemet” is legit. Ask for:

• Certificate of Conformance (CoC) from the original manufacturer – not a third‑party tested copy
• Lot date code – for high‑reliability parts, older stock can have degraded solderability
• ESD compliance statement – connectors and capacitors can be damaged by static; the packaging should be ESD‑shielded

Per FTC guidelines (ftc.gov), claims like “industrial grade” or “military grade” must be substantiated. If a distributor says “Kemet T491 equivalent,” demand the proof. A red flag? They can’t produce an original manufacturer date code or lot number. Walk away.

Step 4: Map Out Lead Times – Not Just “In Stock”

I asked for “as soon as possible.” Supplier heard “whenever convenient.” Result: delivery two weeks later than my production schedule allowed. That’s a communication failure that cost us $4,200 in overtime. Now I always ask three questions:

1. What’s the actual factory lead time for this Kemet part number? (not the distributor’s warehouse stock)
2. What’s the drop‑dead latest delivery date? (give them a hard deadline, not “ASAP”)
3. What happens if it’s late? (penalties, expediting fees, backup plan)

For connectors from Kemet, lead times can be 12–16 weeks if the raw materials (e.g., liquid crystal polymer) are back‑ordered. Always ask for a commitment schedule in writing. The 5 minutes you spend clarifying delivery terms can prevent a 5‑day production halt.

Step 5: Review Reliability Data and Test Reports

The “cheap” alternative failed after 500 hours of operation. That $0.10 difference per unit turned into a $1,200 redo when quality failed. Prevention beats cure every time. I don’t rely on the distributor’s word – I ask for test data:

• Life test results (e.g., 85°C/85%RH, 1000 hours for tantalum capacitors)
• ESR vs. frequency curves – especially for Kemet T491 in power‑supply designs
• Mechanical drawings for connectors – verify footprint, mating cycle count, and retention force

If the supplier can’t provide a full test report within 24 hours, that’s a red flag. I’ve seen counterfeit “Kemet” parts come with photocopied datasheets – the real ones have lot‑specific traceability. Honest, I wasn’t expecting to need this level of detail when I started, but after tracking 200+ orders, it’s the single biggest quality differentiator.

Common Mistakes (And How to Avoid Them)

• Assuming “group” means a price break – “Kemet group” sometimes appears in document titles for multi‑part numbers; it doesn’t automatically give you a volume discount. Verify pricing for each line item.
• Ignoring the “3310” designation – that could be a specific Kemet connector series (e.g., automotive‑grade). If you substitute with a generic “what is a connector” part, you might lose vibration resistance or IP rating.
• Not asking “what is a connector” from a spec perspective – many buyers think all connectors are interchangeable. They aren’t. Check pin pitch, current rating, and locking mechanism against your mating connector.

Remember: the 5 minutes you spend on each step is the cheapest insurance you’ll ever buy. I’ve saved an estimated $8,000 in potential rework just from using this checklist.