2835 LED: The Practical Sourcing Guide for 2025 (For U.S. Wholesale Buyers)

2835 LED Sourcing Guide 2025: Meaning, Wattage, Dimming & 2835 vs 5050New York wholesalers: learn what “2835” really means, calculate true watts, spec flicker-safe dimming, avoid SMT pitfalls, and choose 2835 vs 5050 by $/kilolumen. RFQ lines included.

Your supplier pages shout “SMD 2835 high-efficiency,” but skip the answers you stake profit on: What is 2835? How many watts? Is it truly dimmable? What does SMD change? 2835 vs 5050?

Miss just one and you ship zebra-tinted shelves, fight flicker complaints, cook strips, and burn weekends on RMAs.

Use this field-tested guide: five straight answers, buyer-grade checklists, and copy-paste RFQ lines you can send vendors today.

Think in millimeters first, do I×Vf, demand flicker metrics, control reflow voids, and compare by $/klm landed—not brochure hype.

If you buy LEDs into New York, you’ve probably Googled at 11:59 p.m.: “What does 2835 LED mean?”, “How many watts is it really?”, “Is 2835 dimmable?”, “What is SMD?”, and “Which is brighter—2835 or 5050?” Those five questions quietly decide whether your rollout is boring (good) or chaotic (expensive).

Start with geometry. 2835 is a 2.8 × 3.5 mm package footprint, not a brightness grade. Inside the rectangle: a mid-power InGaN die, phosphor blend, and an exposed thermal pad that dumps heat into copper. That geometry thrives on 8–12 mm PCBs at tight pitch (≈120 LEDs/m), giving smooth diffusion behind typical retail diffusers.

Next, watts. Catalog “0.2 W” can be misleading because real power = current × forward voltage. Drive current up without upgrading the thermal path and that “0.2 W” device quietly operates like 0.36–0.5 W. Junction temperature (Tj) climbs, lumen maintenance slips, and white points drift.

Dimming is not a checkbox; it’s a measurement plan. Procurement should ask for IEEE 1789 flicker metrics (Percent Flicker, Flicker Index) and require PWM ≥ 2–4 kHz or CCR. Color should remain stable at low duty; some phosphor blends smear or warm.

“SMD” means surface-mount device—reflowed assembly. It reduces labor and yields better thermals if your stencil/paste/profile control voids under the thermal slug. Miss that, and heat resistance jumps—lifetime drops.

Finally, brightness economics. Per package, 5050 punches harder and still rules RGB. But on dense white strips, normalized to $/kilolumen landed (unit + freight + duty + bin premiums), 2835 often wins with calmer thermals and cleaner diffusion.

Below are five PAS-driven sections you can drop into Wix. Each includes a skimmable lead, a 200+ word snippet, a swap-ready image, and an in-depth paragraph with pseudo-links you can wire later (e.g., SOPs, calculators). XGM (Shenzhen Xinguanming)—14 years of LED R&D, 3,000+ customers—can provide matched-bin lots plus LM-80/TM-21, EN 62471, RoHS/REACH PDFs.

1·Start With Millimeters: What “2835” Actually Means

“2835” = 2.8 × 3.5 mm mid-power SMD package with an exposed thermal pad—geometry first, brightness second.

Teams treat “2835” like a lumen class and swap reels across vendors expecting identical light.That’s how you get zebra tints, hotspotting behind diffusers, and slow SMT because polarity/leadframe differ.Treat 2835 as geometry + color policy. The format uses a reflective leadframe and exposed heat slug soldered to copper. It shines on 8–12 mm PCBs at ≈120 LED/m, producing uniform light at modest current. For color, Ra80 bins lead on efficiency; Ra90 sacrifices a little lm/W to lift R9—critical for retail, beauty, food, and medical-aesthetic spaces. Lock consistency with ≤3 SDCM (general) or ≤2 SDCM (camera/retail). Ask for native (not screenshots) LM-80/TM-21 reports and EN 62471 safety PDFs from accredited labs—this shortens corporate due diligence. Quick primer: 2835 package cheatsheet · SDCM explainer

Specs to lock in drawings/RFQs:

Thermal path: target RθJC ≤ 12 °C/W; add staggered micro-vias under the slug; use 2-oz copper on FR-4 for ~0.2–0.24 W; step to MCPCB once you cross ≈0.30–0.36 W. Reference: pad & via guide

Materials & environment: silver-mirror leadframes lift lm/W; near leather/rubber, specify anti-sulfur encapsulant. Policy: anti-sulfur checklist

Color control: shipment ≤2 adjacent bins; reel cert lists CCT, Duv, Ra, R9, lm, Vf, lot. Template: bin map + reel cert

SMT hygiene: share pad/stencil files; lock polarity across EMS lines. Drawing: 2835 pad & stencil

RFQ (paste-ready)“2835 package (2.8×3.5 mm) with exposed pad; RθJC ≤ 12 °C/W; ≤3 SDCM (≤2 optional); anti-sulfur encapsulant; native LM-80/TM-21 & EN 62471 PDFs.”

2·How Many Watts Is a 2835 LED? Do I×Vf—Then Guard Tj

Watts aren’t a label—they’re current × forward voltage. Lifetime lives and dies with junction temperature.

A “0.2 W” 2835 gets installed and driven like 0.36–0.5 W on thin FR-4.Tj spikes, L70 shrinks, white points drift, and RMAs stack up.Use real math: Pd = I × Vf from your driver current and the supplier’s Vf histogram. Typical: 65 mA × ≈2.9 V ≈ 0.19 W (FR-4 OK). Push to ≈120 mA × ≈3.0 V ≈ 0.36 W and you must upgrade the heat path (MCPCB or heavy copper) to keep Tj ≤ ≈105 °C. Need more lumens? Under-drive and add emitters; eight 2835s at ~65 mA spread heat, keep lm/W high, and tame hotspots better than cranking a few LEDs. Keep driver ripple < 5 %—peaks, not averages, stress phosphor and the die. Calculator: I×Vf + thermal sheet · Primer: driver ripple explainer

Controls that prevent surprises:

Vf window & distribution: spec typ 2.8–2.9 V; max 3.1 V @ 65 mA and request the histogram, not just min/max. Guide: reading Vf plots

String strategy: prefer series; if paralleling, use balancing resistors or matched copper to prevent current hogging. Note: parallel best-practice

Driver topology: constant-current buck; spread-spectrum PWM reduces EMI and peak current overshoot. Card: driver quick wins

Thermal step-up: beyond ≈0.30–0.36 W/LED, migrate to MCPCB; verify Tc with thermocouples and extrapolate Tj. SOP: thermal check card

RFQ (paste-ready)“Quote lm/W at 65 mA and at our max current; include Vf histogram, RθJC data, ΔVf after 1,000 h @ 85 °C/IFnom, and derating curve.”

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

Use 2–4 kHz PWM or CCR, enforce IEEE 1789 metrics, and cap low-level color shift.

Constant-voltage strips on triac dimmers create ripple and banding on camera.Guests see strobe, staff report headaches, reviews say “flicker,” and your brand eats it.Specify drivers that publish Percent Flicker and Flicker Index aligned to IEEE 1789. Put limits in writing: Percent Flicker < 10 % and Flicker Index < 0.05 at 100 % output; then re-test at ~20 %, where cheap drivers fail. Ask for phosphor decay curves; fast-decay mixes track PWM more faithfully (less smear), while slow-decay can hide strobe but warms CCT at low duty. Require Δu′v′ ≤ 0.003 from 100 % → 10 % at Tc 25/55 °C so whites stay consistent in hospitality, retail, and education. Quick pack: IEEE-1789 cheat-sheet · low-duty SOP

Deployment checklist you can hand to engineering:

Driver mode: PWM ≥ 2 kHz (4 kHz ideal) or CCR; optional shunt FET prevents ghosting below ~2 % duty. Matrix: dimmer compatibility

EMI & ringing: spread-spectrum controllers limit peaking; keep LED-to-driver traces short with solid returns. Card: layout quick wins

Proof pack: provide oscilloscope screenshots at 100 % and 20 % on your load, with Percent Flicker/Flicker Index (and Pst_LM/SVM if spec’d). Template: flicker report pack

Color stability: verify CCT and Δu′v′ vs dim level for the exact Ra80/Ra90 recipe you’ll buy. Plan: Δu′v′ test method

RFQ (paste-ready)“Provide IEEE 1789 flicker metrics and Δu′v′ vs dim level using our driver; attach scope screenshots at 100 % and 20 % output.”

4·What SMD Actually Changes: Reflow Quality = Lifetime

SMD is a process promise: stencil, paste, and profile decide voids—and voids decide RθJA, yield, and warranty.

“One stencil fits all” invites under-slug voids and tombstoning on 2835 pads.Voids raise RθJA, shorten life, and wreck yields; missed go-lives cost more than any paste upgrade.For 2835, use 0.12–0.15 mm stencils and type-4/4.5 paste; ramp < 3 °C/s, peak 245 ± 5 °C (nitrogen preferred). X-ray first articles; if under-slug void area exceeds ≈30 %, tune apertures or add a soak segment. Prefer no-clean flux to avoid moisture under lenses; bake PCBs stored > 6 months. Share a one-page reflow card before the build so operators don’t guess your process. Starters: SMT setup checklist · void-control guide

On-floor controls that pay back:

Area ratio ≥ 0.66 for reliable paste transfer; consider step stencil over the thermal pad. Tips: aperture tuning

Paste bricks aligned to copper fill to limit float/skew; keep lens shadowing off pads. Card: stencil & pad playbook

Sampling & rejection: follow IPC-7093 X-ray sampling; reject lots with repeat void hot-spots; tweak soak/peak dwell accordingly. Grid: X-ray acceptance matrix

Cleaning policy: avoid water-soluble flux under lenses; if used, validate wash + bake and re-verify Δu′v′ on white LEDs. SOP: post-wash color check

RFQ (paste-ready)“Provide pad layout, stencil guidance, max under-slug void %, and recommended reflow curve for the quoted 2835; confirm IPC-7093 compliance.”

5·Which Is Brighter—2835 or 5050? Choose by Use Case & $/klm Landed

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

Teams compare single-package lumens and ignore density, driver channels, and heat load.You overbuy 5050s, drivers run hot, diffuser hotspots show, and BOMs balloon.Normalize quotes to $/kilolumen landed (unit + freight + duty + bin premiums). A white 5050 (often multi-die) out-punches a 0.2 W 2835 per package, so it dominates RGB and “punchy” white modules. But eight 2835s at ~65 mA spread heat, keep lm/W high, and often beat three 5050s on $/klm once drivers and logistics hit the invoice. For outdoor “punch,” 5050 white works—derate ≈20 % and add surge protection. Tools: $/klm calculator · use-case matrix

Fast decision matrix you can paste into team notes:

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

Stage/architectural RGB → 5050 (addressable or non-addressable); PWM & EMI demands raise BOM. Notes: RGB driver tips

Outdoor signage → 5050 white + thermal derating + robust surge design. Spec: surge & derate card

Supply risk → 2835 whites are broadly second-sourced; some addressable 5050s bind you to one IC vendor. Plan: dual-source guide

RFQ (paste-ready)“Quote 2835 white (Ra80 & Ra90) and 5050 white/RGB as $/pc and $/klm landed (FOB & DDP New York). Include SDCM, RθJC, IEEE 1789 metrics, surge limits, and lead time.”

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 %—retest at ~20 %.

Compliance: LM-80/TM-21, EN 62471, RoHS/REACH—native PDFs only.

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