2835 LED Buyer Answers (2025): Footprint, Watts, Dimming, SMD Basics & 2835 vs 5050

2835 LED Explained: Watts, Dimming & 2835 vs 5050

Plain-English answers to: what 2835 means, real wattage, dimming rules, SMD basics, and which is brighter—2835 or 5050. RFQ-ready specs for U.S. wholesale buyers.

Problem — Supplier pages shout “SMD 2835 high-efficiency,” but skip the numbers you need to quote confidently and avoid RMAs.

Agitate — Choose the wrong chip and you’ll overheat strips, fight dimmer flicker, and ship zebra-striped shelves that ruin reviews.

Solution — Use the five sections below to lock footprint, wattage, dimming, assembly, and 2835-vs-5050 decisions—plus copy-ready RFQ lines at the end.

Know the package, calculate watts, dim smoothly, reflow right, and pick 2835 or 5050 based on $/klm, not brochure hype.

If you’re buying for New York distribution, your search history probably includes “What does 2835 LED mean?”, “How many watts is a 2835?”, “Is 2835 dimmable?”, “What does SMD mean?”, and “Which is brighter, 2835 or 5050?” Those five questions decide whether your next rollout ships clean—or turns into late-night support calls and returns.

Quick orientation:

2835 is a 2.8 × 3.5 mm mid-power SMD footprint with an exposed thermal pad. In modern bins, Ra80 whites typically deliver high lm/W at ~65 mA, with Ra90 options trading a bit of efficiency for better reds (R9).

Watts aren’t printed on the case. They’re I × Vf. Double current without upgrading thermals and you silently jump from ~0.2 W to ~0.36–0.5 W.

Dimming works when drivers meet IEEE 1789 guidance (Percent Flicker / Flicker Index) and phosphor latency doesn’t smear color at low duty.

SMD means surface-mount; it slashes assembly cost and improves heat flow—if your stencil and reflow keep voids low.

Brightness: 5050 wins per-package punch and rules RGB; 2835 often wins $/kilolumen and heat spread on dense white strips.

Below, each section uses a micro-PAS flow—call out the common mistake (Problem), amplify the risk (Agitate), then give you concrete specs/tests (Solution). We also weave in quick E-E-A-T cues (LM-80/TM-21, EN 62471) to satisfy auditors and Google. Copy the RFQ snippets straight into vendor emails; XGM (Shenzhen Xinguanming) can match bins, share native PDFs, and ship pilot lots against these specs.

1·The 2.8×3.5 mm Form Factor that Dominates Strips

“2835” is just the size—2.8 × 3.5 mm—with an exposed pad for heat and pitch-friendly geometry for smooth, uniform strips.

Problem. Many teams treat “2835” like a brightness grade, then mix incompatible reels.Agitate. The result? Mismatched optics, poor thermals, and color tint differences across shelves.Solution. Treat 2835 as a footprint: a mid-power SMD package with a reflective leadframe and exposed thermal slug. Its geometry lets you run 120 LED/m strips with even diffusion while keeping a practical copper area under the die. In current production, quality Ra80 bins deliver high efficacy at ~65 mA; Ra90 is slightly lower but offers R9-rich reds for retail. Lock color consistency via ≤3 SDCM (general) or ≤2 SDCM (premium/camera). Require LM-80/TM-21 PDFs and EN 62471 risk group (RG0/RG1) to pass audits. Done right, 2835 balances efficacy, density, and cost better than older 3528—and avoids the hotspotting common with bigger tri-die packages.

Design details that matter:

Leadframe reflectivity boosts lm/W; specify anti-sulfur encapsulant for leather/rubber displays. See sulfur mitigation tips.

Phosphor uniformity controls green/pink tint; request Δu′v′ drift plots over aging.

Pad/via strategy: staggered micro-vias under the slug reduce voids and keep RθJA low.

Polarity discipline: match the cathode marker across all EMS lines to avoid reflow attrition.

RFQ line: “2835 package 2.8×3.5 mm, exposed thermal pad; RθJC ≤ 12 °C/W; ≤3 SDCM (≤2 optional); anti-sulfur encapsulant; provide LM-80/TM-21 (ISO/IEC 17025) and EN 62471.”Useful maps: ANSI bin ellipse template · pad & stencil card

2·Wattage Reality Check: Calculate Power the Way Drivers See It

Watts = I × Vf. Current, voltage, and thermal resistance—not a catalog blurb—decide lifetime.

Problem. Teams quote “0.2 W 2835” and later drive at double current.Agitate. Junction temps spike, L70 craters, and color drifts—killing margins.Solution. Use your actual driver current and a supplier Vf histogram to compute Pd = I × Vf. At ~65 mA × ~2.9 V you’re ~0.19 W; at 120 mA × 3.0 V you’re ~0.36 W—fine on MCPCB, risky on thin FR-4. Estimate ΔT = Pd × RθJC and add board-to-ambient to get Tj. Keep Tj ≤ ~105 °C for reliable lumen maintenance. If you need more flux, under-drive more emitters instead of over-driving a few; strip efficacy improves and hotspots vanish. Control driver ripple (<5 %) so peak current doesn’t silently overstress the die.

Stabilize wattage with:

Tighter Vf window (typ 2.8–2.9 V; max 3.1 V @ 65 mA). Ask for the distribution, not just min/max.

Balanced strings—series is safest; if you must parallel, add balancing resistors.

Spread-spectrum PWM—reduces EMI and current peaking.

Substrate upgrade—move to MCPCB beyond ~0.3–0.36 W per LED.

“Quote lm/W at 65 mA and at our max current. Provide Vf histogram, RθJC data, and ΔVf after 1 000 h @ 85 °C/IFnom.”

3·Dimming Without Flicker: Make 2835 Behave on Real Drivers

Use 2 kHz+ PWM or CCR and verify IEEE 1789 metrics; check color drift at low duty.

Problem. Constant-voltage strips on triac wall dimmers produce ripple and banding.Agitate. Customers see strobe on camera; hospitality staff complain of headache-inducing flicker.Solution. For most installs, PWM ≥ 2–4 kHz keeps Percent Flicker low. For camera-critical sites, use CCR (constant-current reduction). Put two limits in writing: Percent Flicker < 10 % and Flicker Index < 0.05 at 100 % output. Then test at 20 %—cheap drivers spike there. Request a phosphor decay curve; fast-decay mixes track PWM better, while slow-decay can warm CCT but hide strobe. Verify Δu′v′ ≤ 0.003 from 100 % → 10 % at Tc 25/55 °C for color stability.

Your dimming checklist:

Driver—PWM (≥2 kHz) or CCR; add a shunt FET to avoid ghosting <2 % duty.

EMI—prefer controllers with spread-spectrum modulation.

Metrics—capture Percent Flicker, Flicker Index; add Pst_LM/SVM if spec’d by the site.

Board layout—short LED-to-driver traces reduce ringing and surges.

RFQ line: “Provide IEEE 1789 flicker metrics and Δu′v′ vs dim level on our driver. Include oscilloscope screenshots at 100 % and 20 % output.”Deep dive: flicker & decay cheat-sheet · low-duty test SOP

4·SMD in Practice: Assembly & Thermal Wins You Can Bank On

SMD = faster assembly and better thermals—if stencil, paste, and reflow keep slug voids low.

Problem. “Same stencil for everything” invites voids and tombstoning.Agitate. Voids inflate RθJA, shortening life; skew causes rejects and delays.Solution. For 2835, run 0.12–0.15 mm stencil, type-4/4.5 paste, ramp <3 °C/s, peak 245 ± 5 °C (nitrogen preferred). X-ray first articles: if void area > ~30 % under the thermal slug, tune apertures or soak. Use no-clean flux to avoid moisture under the lens. Bake PCBs stored >6 months. Share a reflow card with EMS to stop blame games and keep yields high.

Implementation notes:

Area ratio ≥ 0.66 for consistent paste transfer; step the thermal pad if necessary.

Aperture reductions limit float and skew; align paste bricks with copper fill.

IPC-7093 sampling—reject lots with repeat void hotspots; adjust soak segment.

RFQ line: “Provide pad layout, stencil guidance, max void %, and recommended reflow curve for the quoted 2835; confirm IPC-7093 compliance.”References: SMT setup card · void-control guide

5·Brightness Matchup: When 2835 Beats 5050

Per package, 5050 is brighter; per $/klm on dense white strips, 2835 usually wins. RGB? 5050 still rules.

Problem. Teams compare single-package lumens and ignore strip-level economics.Agitate. You overbuy 5050s, drivers run hot, and BOMs balloon.Solution. Normalize to $/kilolumen and consider strip density. A single white 5050 (often multi-die) can output strong lumens at higher current, but eight 2835s at ~65 mA spread heat and typically beat three 5050s on $/klm once you add driver channels and freight/duty. For RGB, 5050’s tri-die construction (separate R/G/B) is mandatory. For outdoor “punch,” 5050 white works—just derate current ~20 % for heat.

Decision matrix:

Retail/task/appliance → 2835 white, ≤3 SDCM (≤2 premium), Ra80/Ra90 per channel.

Stage/architectural RGB → 5050 (with or without IC).

Outdoor signage → 5050 white; thermal derating and robust surge protection.

Supply risk → 2835 whites are widely second-sourced; addressable 5050s may lock you to one IC vendor.

RFQ line: “Quote 2835 white (Ra80 & Ra90) and 5050 white/RGB as $/pc and $/klm landed (FOB & DDP NY). Include SDCM, RθJC, IEEE 1789 metrics, and surge limits.”Tools: $/klm calculator · 2835 vs 5050 worksheet

Binning: ≤3 SDCM (≤2 premium); shipment ≤2 adjacent bins; reel cert lists CCT, Duv, Ra, R9, lm, Vf, lot.

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, Δu′v′ ≤0.006.

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

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

Optional FAQ

What does 2835 LED mean?The 2.8 × 3.5 mm SMD footprint—mid-power package with an exposed thermal pad.

Is 2835 LED dimmable?Yes—with 2 kHz+ PWM or CCR drivers and IEEE 1789-checked flicker.

Which is brighter, 2835 or 5050?Per package, 5050; per $/klm on dense white strips, 2835.