2835 LED, Plain-English Answers (2025): Meaning, Real Wattage, Dimming Rules, SMD Basics & 2835 vs 5050

Meta title: 2835 LED Explained: Watts, Dimming, SMD & 2835 vs 5050

Meta description: What “2835” means, how many watts it draws, if it’s dimmable, what SMD is, and whether 2835 or 5050 is brighter—RFQ-ready answers for U.S. buyers.

Problem — Supplier pages shout “SMD 2835 high-efficiency,” but they skip the numbers you actually need to quote and install with confidence.

Agitate — Pick the wrong spec and you’ll overheat strips, fight flicker on dimmers, and eat RMAs when color shifts green.

Solution — Use the five answers below—clear watt math, dimming metrics, SMD assembly notes, and a 2835-vs-5050 brightness rule—then paste the RFQ lines into your next vendor email.

Know the footprint, calculate watts, dim without flicker, reflow SMDs right, and choose 2835 or 5050 based on lumen-per-dollar—not brochure promises.

If you’re a New York–based wholesaler, your search history probably includes “What does 2835 LED mean?”, “How many watts is a 2835?”, and “Is 2835 dimmable?”—right next to “Which is brighter, 2835 or 5050?” Those are the questions that separate a smooth rollout from a support nightmare. Yet many articles repeat marketing copy instead of giving you purchase-grade numbers: package footprint, forward-voltage window, current range, RθJC (junction-to-case thermal resistance), SDCM binning for color uniformity, and IEEE 1789 flicker metrics for dimming.

Here’s the fast orientation for 2025:

“2835” is the package size: 2.8 mm × 3.5 mm. It’s a mid-power SMD format with a solid thermal pad. In current bins, Ra80 whites reach ~140–165 lm/W @ 65 mA; Ra90 options land around ~130 lm/W with R9 ≥ 50.

Watts change with current and Vf. That catalog “0.2 W” assumes ~65 mA at ~2.9 V. Push current and you’re quietly at 0.36–0.5 W—great for flux, brutal for lifetime unless you upgrade the heat path.

Dimming is fine—if your driver is 2 kHz+ PWM (or CCR) and the phosphor mix isn’t slow. Otherwise: flicker, banding, and color smear.

SMD simply means surface-mount device: reflowed parts with lower labor and better heat transfer when your stencil and profile keep voids low.

Brightness choice: 5050 wins per-package punch and rules RGB; 2835 often wins $/kilolumen on dense white strips with gentler thermals.

Below, each section follows PAS: a common pitfall (Problem), why it hurts (Agitate), and the exact spec or test (Solution). You’ll also see practical RFQ sentences and quick references you can share with engineering or finance, using internal placeholders like binning guide and flicker checklist. Copy what you need, and if you want XGM to pre-bin and ship a pilot lot, the contact block at the end is ready.

1·The 2.8×3.5 mm “2835” Footprint—Why This Size Won for Strips

“2835” = 2.8 mm × 3.5 mm mid-power SMD with an exposed thermal pad that balances lm/W, density, and reflow yield.

Most confusion starts here: 2835 isn’t a lumen rating—it’s a size code. Inside the rectangular package lives a single InGaN die on a reflective silver leadframe, capped with phosphor and tied to an exposed heat slug. That geometry packs tightly on 8–12 mm strip PCBs, delivers smooth diffusion at 120 LED/m, and gives you a direct thermal path into copper. In 2025, good Ra80 bins hit ~140–165 lm/W @ 65 mA, while Ra90 options trade a little efficacy for R9 ≥ 50 (better reds). Color consistency is controlled by SDCM—stick to ≤3 SDCM for general, ≤2 SDCM for retail and camera work.

Because the slug contacts copper, 2835 tolerates 0.2–0.24 W on FR-4 with vias; for 0.36–0.5 W you’ll want MCPCB or hefty copper. This footprint also plays nicely with automated assembly: standard 0.12–0.15 mm stencils, type-4 paste, and modest reflow tweaks get you high first-pass yield. See package pads & polarity and the ANSI bin map template here.

Details worth checking:

Leadframe reflectivity boosts lm/W but can darken in sulfur-rich environments; specify anti-sulfur encapsulant for leather/rubber displays. Quick brief: sulfur mitigation.

Phosphor uniformity controls green-pink tint; ask for Δuʹvʹ stability data over time.

Polarity & pad design: keep the cathode marker orientation consistent; stagger thermal vias to prevent voids (reflow note).

RFQ line: “2835 package 2.8×3.5 mm with exposed pad; RθJC ≤ 12 °C/W; ≤ 3 SDCM (≤ 2 optional); anti-sulfur encapsulant; provide LM-80/TM-21 PDFs from ISO/IEC 17025 lab.”

2·How Many Watts Is a 2835 LED? (Do the Math, Avoid the Melt)

Watts aren’t a label; they’re I × Vf. Current, voltage, and RθJC decide lifetime.

That catalog “0.2 W” assumes ~65 mA × ~2.9 V = ~0.19 W. Chase brightness to 120 mA × 3.0 V and you’re at 0.36 W—fine on MCPCB, risky on thin FR-4. Always compute Pd = I × Vf from your actual driver and the supplier’s Vf histogram. Then estimate ΔT = Pd × RθJC; add board-to-ambient (RθCA) and cabinet heat to get Tj. If Tj crosses ~105 °C, LM-80 curves won’t save you—L70 falls and color drifts.

Safer play: under-drive and add emitters. Eight 2835s at 65 mA spread heat and yield better lm/W than three 5050s run hot. Keep driver ripple ≤ 5 % so peak current doesn’t silently over-stress the die. Use our quick sheet: watt/thermal calculator.

Controls that keep watts sensible:

Vf window—spec typ 2.8–2.9 V; max 3.1 V @ 65 mA and ask for the histogram (Vf primer).

Parallel balance—use series strings or balancing resistors; lowest-Vf parts otherwise hog current.

Driver topology—pick CC buck with spread-spectrum PWM to reduce EMI and ripple spikes.

Substrate—crossing 0.3–0.36 W? Move to MCPCB before the junction cooks.

RFQ line: “Quote lm/W at 65 mA and at our max current; provide Vf distribution, RθJC data, and ΔVf after 1 000 h @ 85 °C/IFnom.”

Reference: derating curve template.

3·Is 2835 Dimmable? (Yes—If You Respect Flicker Physics)

Use 2 kHz+ PWM or CCR; verify IEEE 1789 metrics and low phosphor latency.

Modern 2835 whites dim cleanly down to ~5 % duty with 2–4 kHz PWM. Trouble starts when constant-voltage strips hit triac wall dimmers—ripple explodes, Percent Flicker jumps, cameras show banding, and some phosphor blends smear color at low duty. For hospitality, museums, or on-camera sets, prefer CCR drivers or PWM with spread-spectrum. Put numbers in writing: Percent Flicker < 10 % and Flicker Index < 0.05 at full output; spot-test at 20 % where cheap drivers spike. Ask for a phosphor decay curve; fast-decay mixes track PWM better, while slow-decay can mask flicker but warms CCT. Quick explainer: IEEE 1789 cheat-sheet.

Dimming checklist:

Driver—PWM ≥ 2 kHz (or CCR), shunt FET to prevent ghosting < 2 % duty, and spread-spectrum to cut EMI.

Color stability—require Δuʹvʹ ≤ 0.003 from 100 % → 10 % at Tc 25/55 °C (color drift notes).

Measurements—oscilloscope plus flicker meter; include Pst_LM/SVM if site standards ask.

RFQ line: “Provide IEEE 1789 metrics (Percent Flicker, Flicker Index) and Δuʹvʹ plots vs dim level on our driver.”

More: flicker test SOP.

4·What Does SMD Mean for LED Lights? (Assembly & Heat, Not Hype)

SMD = surface-mount device: faster assembly, better thermals—if your stencil, paste, and profile keep voids low.

SMD LEDs reflow straight onto copper pads. Labor drops, consistency rises, and the exposed pad on 2835 dumps heat into the board—if you control solder volume and voids. Use 0.12–0.15 mm stencil thickness, type-4 (or 4.5) paste, ramp < 3 °C/s, peak 245 ± 5 °C (nitrogen preferred). X-ray the first article: if void area > ~30 % under the slug, RθJA jumps and lifetime falls. Cleanliness counts—residues under the lens wick moisture and push Δuʹvʹ over months. Pad & profile template: SMT setup card.

Shop-floor details that pay dividends:

Area ratio ≥ 0.66 for reliable paste transfer; step stencil on the thermal pad if needed.

Paste bricks—keep aperture reductions to limit float and skew.

No-clean flux—avoid water-soluble under lenses; bake PCBs stored > 6 months.

IPC-7093 sampling—reject lots with consistent void hot-spots; tune reflow soak.

RFQ line: “Share pad layout, stencil guidance, max void %, and recommended reflow curve for the quoted 2835; confirm IPC-7093 compliance.”

Process cheat-sheet: reflow & X-ray.

5·Which Is Brighter—2835 or 5050? (Package Punch vs Strip Economics)

Per package, 5050 is brighter; per lumen-per-dollar on dense white strips, 2835 usually wins. RGB still belongs to 5050.

A single white 5050 (often multi-die) delivers ~210–240 lm @ ~150 mA, out-punching a 0.2 W 2835 at ~60–70 lm. But strip-level math changes the picture: eight 2835s at 65 mA spread heat, sustain lm/W, and often beat three 5050s on $/kilolumen once driver channels and duty land on the invoice. For RGB, 5050’s tri-die construction (separate R/G/B) is mandatory for real color control; 2835 “RGB whites” are compromises.

Decision rule: retail/task/appliance → 2835 whites with tight SDCM; stage/architectural RGB → 5050; outdoor punch → 5050 whites but derate current ~20 % for heat. See cost-to-lumen matrix and MacAdam ellipse explainer.

Normalize quotes before deciding:

$/klm landed (include freight, duty, bin premiums).

CRI/R9 + SDCM (color quality premium).

Thermal headroom (Tj at worst ambient).

Driver BOM (channels for RGB/5050; ripple specs).

Supply risk (addressable IC dependencies for 5050 RGB).

RFQ line: “Quote 2835 white (Ra80 & Ra90) and 5050 white/RGB as $/pc and $/klm landed (FOB & DDP NY); include SDCM, RθJC, IEEE 1789, and surge limits.”

More detail: 2835-vs-5050 worksheet.

Binning: ≤ 3 SDCM (≤ 2 premium); shipment ≤ 2 adjacent bins; provide bin & lot certificate with CCT, Duv, Ra, R9, lm, Vf.

Thermal & Reliability: RθJC ≤ 12 °C/W; HTOL 1 000 h @ 105–125 °C, 85/85 1 000 h, –40↔125 °C 1 000 cycles, surge 10/700 µs to 2 kV; lumen loss ≤ 10 %, ΔVf ≤ 0.1 V, Δuʹvʹ ≤ 0.006.

Dimming: Provide IEEE 1789 metrics; Percent Flicker < 10 %, Flicker Index < 0.05 at 100 % output; verify at 20 %.

Pricing: Quote $/pc and $/klm landed (FOB Shenzhen & DDP New York); itemize bin premiums; include NET-30/NET-60 scenarios.

Want this tailored to your driver and CCT?

Send your target CCT/CRI, drive current, and incoterm. XGM will return matched-bin 2835 samples plus native LM-80/TM-21 and EN 62471 PDFs—so you can evaluate today and place a confident PO tomorrow.