{"id":4271,"date":"2026-06-24T08:42:13","date_gmt":"2026-06-24T08:42:13","guid":{"rendered":"https:\/\/blogs.lcsc.com\/blog\/?p=4271"},"modified":"2026-06-24T08:42:13","modified_gmt":"2026-06-24T08:42:13","slug":"qfn-pcb-layout-guide","status":"publish","type":"post","link":"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/","title":{"rendered":"QFN PCB Layout Guide: Thermal Pad &#038; Solder Void Control"},"content":{"rendered":"<h2><b><span data-font-family=\"Arial\">Takeaway<\/span><\/b><\/h2>\n<ul>\n<li><span data-font-family=\"Arial\"> Size the <a href=\"https:\/\/www.lcsc.com\/pcba\/faq\">PCB<\/a> thermal land 1:1 with the package EPAD (or +0.1\u20130.2\u00a0mm per side maximum).<\/span><\/li>\n<li><span data-font-family=\"Arial\"> Use 9\u201325 thermal vias at \u00d80.3\u20130.33\u00a0mm with solid copper fill \u2014 no thermal relief spokes.<\/span><\/li>\n<li><span data-font-family=\"Arial\"> Design stencil apertures to cover 50\u201375\u00a0% of EPAD area with a windowed or cross-hatch pattern.<\/span><\/li>\n<li><span data-font-family=\"Arial\"> Target \u226590\u00a0% solder coverage beneath the pad; IPC-A-610 sets the production maximum at 25\u00a0% voiding.<\/span><\/li>\n<li><span data-font-family=\"Arial\"><span data-font-family=\"Arial\"> Verify every board with X-ray \u2014 QFN solder joints are invisible to optical inspection.<\/span><\/span><\/li>\n<\/ul>\n<p><span data-font-family=\"Arial\">QFN (Quad Flat No-Lead) packages are the go-to choice for high-density power management, RF, and mixed-signal ICs \u2014 but their hidden solder joints and exposed thermal pad make them one of the most assembly-sensitive packages in surface-mount technology. Done right, a QFN layout achieves junction-to-case thermal resistance (\u03b8JC) as low as 1\u20135\u00a0\u00b0C\/W and lead inductance below 3\u00a0nH per pin. Done wrong, invisible voids beneath the thermal pad cause field thermal failures that only show up under X-ray.<\/span><\/p>\n<h2><b><span data-font-family=\"Arial\">What Is a QFN Package?<\/span><\/b><\/h2>\n<p><span data-font-family=\"Arial\">The Quad Flat No-Lead (QFN) package \u2014 also referred to as Micro Lead Frame (MLF), Micro Lead Package (MLP), or Land Grid Array (LGA) in some manufacturer nomenclatures \u2014 is a surface-mount IC package in which electrical connections are made through copper lands on the bottom surface of the component rather than through perimeter gull-wing leads. Its defining physical feature is the exposed die attach paddle (EPAD): a bare metal thermal pad on the package underside that sits flush with or slightly below the perimeter signal leads.<\/span><\/p>\n<p><span data-font-family=\"Arial\">Package body sizes typically range from 2\u00d72\u00a0mm to 10\u00d710\u00a0mm with lead pitches of 0.4\u00a0mm, 0.5\u00a0mm, or 0.65\u00a0mm, and pin counts from 4 to 100+. The package complies with JEDEC outline MO-220 and is governed by IPC-SM-782 \/ IPC-7351 for PCB land pattern design.<\/span><\/p>\n<p><span data-font-family=\"Arial\">The exposed thermal pad serves a dual purpose: it is the primary thermal conduction path from the silicon die to the<a href=\"https:\/\/blogs.lcsc.com\/blog\/backplane-pcb-design\/\"> PCB copper<\/a> planes, and in the vast majority of devices it is also the electrical ground (VSS) connection. Some regulator and power management ICs route non-ground signals through the EPAD \u2014 always consult the individual device datasheet before connecting the PCB thermal land to a ground plane. Assembly and layout of QFN packages is standardized through JEDEC JESD51-5, IPC-A-610, and J-STD-020.<\/span><\/p>\n<h2><b><span data-font-family=\"Arial\">Why QFN Outperforms SOIC, TSSOP, and QFP<\/span><\/b><\/h2>\n<p><span data-font-family=\"Arial\">The QFN package was developed to address the thermal and electrical limitations of traditional leaded surface-mount packages as IC power densities and operating frequencies increased. Conventional SOIC and TSSOP packages route heat through thin lead fingers and into the board via solder fillets \u2014 a thermal path with inherently high resistance. The QFN eliminates this bottleneck by placing the exposed die paddle in direct contact with the PCB copper plane through a soldered interface, reducing junction-to-board thermal resistance (\u03b8JB) by 40\u201370\u00a0% compared to equivalent leaded packages. At the same time, the elimination of lead frames reduces parasitic inductance per pin to approximately 1\u20133\u00a0nH, compared to 5\u201310\u00a0nH typical of gull-wing leads.<\/span><\/p>\n<h2><b><span data-font-family=\"Arial\">Key Features and Advantages<\/span><\/b><\/h2>\n<table>\n<tbody>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"186.66666666666666\"><b><span data-font-family=\"Arial\">Feature<\/span><\/b><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"232\"><b><span data-font-family=\"Arial\">Description<\/span><\/b><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"205.33333333333334\"><b><span data-font-family=\"Arial\">Benefit<\/span><\/b><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"186.66666666666666\"><span data-font-family=\"Arial\">Exposed Thermal Pad (EPAD)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"232\"><span data-font-family=\"Arial\">Die attach paddle soldered directly to PCB copper plane via thermal vias<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"205.33333333333334\"><span data-font-family=\"Arial\">Achieves \u03b8JC as low as 1\u20135\u00a0\u00b0C\/W; enables high-power density in compact footprint<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"186.66666666666666\"><span data-font-family=\"Arial\">Ultra-Low Lead Inductance<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"232\"><span data-font-family=\"Arial\">Leadless bottom contacts reduce parasitic inductance to 1\u20133\u00a0nH per pin<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"205.33333333333334\"><span data-font-family=\"Arial\">Critical for RF, high-frequency switching, and fast transient power management<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"186.66666666666666\"><span data-font-family=\"Arial\">Small Footprint<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"232\"><span data-font-family=\"Arial\">Body sizes 2\u00d72\u00a0mm to 10\u00d710\u00a0mm; pitch 0.4\u20130.65\u00a0mm<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"205.33333333333334\"><span data-font-family=\"Arial\">Frees PCB real estate vs. SOIC\/TSSOP\/QFP equivalents with same pin count<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"186.66666666666666\"><span data-font-family=\"Arial\">Dual Thermal\/Electrical Ground<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"232\"><span data-font-family=\"Arial\">EPAD typically serves as VSS contact and primary heat path simultaneously<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"205.33333333333334\"><span data-font-family=\"Arial\">Reduces pin count for power\/ground routing; simplifies decoupling layout<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"186.66666666666666\"><span data-font-family=\"Arial\">IPC\/JEDEC Standardized Assembly<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"232\"><span data-font-family=\"Arial\">Governed by MO-220, IPC-7351, IPC-A-610, J-STD-020, JESD51-5<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"205.33333333333334\"><span data-font-family=\"Arial\">Predictable assembly process with industry-wide tooling and inspection support<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"186.66666666666666\"><span data-font-family=\"Arial\">Package Variant Range<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"232\"><span data-font-family=\"Arial\">TQFN (Thin), VQFN (Very Thin), Dual-Row, Multi-Row configurations<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"205.33333333333334\"><span data-font-family=\"Arial\">Adapts to height-constrained, high-I\/O, and fine-pitch applications<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2><b><span data-font-family=\"Arial\">How to Design the Thermal Pad and Via Array<\/span><\/b><\/h2>\n<p><span data-font-family=\"Arial\">The thermal pad is the central design challenge of any QFN assembly. The PCB thermal land should match the EPAD dimensions closely \u2014 typically 1:1 with the package pad or marginally larger by 0.1\u20130.2\u00a0mm per side \u2014 and must be connected to inner copper planes through an array of thermal vias.<\/span><\/p>\n<p><span data-font-family=\"Arial\">Via diameter of 0.3\u20130.33\u00a0mm with minimum 1\u00a0oz copper barrel plating is standard. Solid-fill connections between vias and the thermal pad (without thermal relief spokes) are mandatory \u2014 thermal relief webs introduce resistive constrictions that defeat the purpose of the via array. Thermal improvement becomes asymptotic above approximately 25 vias, so practical designs target 9\u201325 vias arranged in a regular grid within the EPAD footprint.<\/span><\/p>\n<h4><b><span data-font-family=\"Arial\">Thermal Via Quick Reference<\/span><\/b><\/h4>\n<p><span data-font-family=\"Arial\">Diameter: 0.30\u20130.33\u00a0mm | Copper plating: \u22651\u00a0oz (35\u00a0\u00b5m) barrel<\/span><\/p>\n<p><span data-font-family=\"Arial\">Via count: 9\u201325 (minimum 8 for 36-pin; \u226516 for 6\u00d76\u00a0mm EPAD)<\/span><\/p>\n<p><span data-font-family=\"Arial\">No thermal relief spokes. Solid connection to thermal pad required.<\/span><\/p>\n<p><span data-font-family=\"Arial\">Fill type: tented, plugged, or copper-filled to prevent solder wicking.<\/span><\/p>\n<h2><b><span data-font-family=\"Arial\">Stencil Aperture Design and Void Prevention<\/span><\/b><\/h2>\n<p><span data-font-family=\"Arial\">Solder voiding beneath the EPAD is the most common assembly defect and the primary driver of field thermal failures in QFN designs. Voids form when flux outgassing volatiles become trapped between the paste and the package during reflow. IPC-A-610 sets the maximum acceptable void area at 25\u00a0% of the thermal pad area for production assemblies, while Analog Devices recommends targeting 90\u00a0% or better solder coverage \u2014 with the recognition that voiding exceeding 50\u00a0% can have a catastrophic effect on \u03b8JB by disconnecting thermal vias from the heat source.<\/span><\/p>\n<p><span data-font-family=\"Arial\">The stencil design is the primary tool for void control: apertures subdivided into a grid or cross-hatch pattern covering 50\u201375\u00a0% of the EPAD area create natural channels for flux gas to escape during reflow soak. For designs using encroached vias, 70\u201375\u00a0% coverage is recommended per Microchip AN18.15; for standard through-vias, 65\u00a0% is the typical target. Web thickness between aperture openings should be a minimum 0.2\u20130.3\u00a0mm.<\/span><\/p>\n<h2><b><span data-font-family=\"Arial\">Technical Specifications<\/span><\/b><\/h2>\n<table style=\"height: 1659px;\" width=\"679\">\n<tbody>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><b><span data-font-family=\"Arial\">Parameter<\/span><\/b><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><b><span data-font-family=\"Arial\">Value \/ Range<\/span><\/b><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Package Standard<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">JEDEC MO-220; IPC-SM-782 \/ IPC-7351<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Body Size Range<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">2\u00d72\u00a0mm to 10\u00d710\u00a0mm (common: 3\u00d73, 4\u00d74, 5\u00d75, 6\u00d76, 7\u00d77, 8\u00d78\u00a0mm)<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Lead Pitch<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">0.4\u00a0mm, 0.5\u00a0mm, 0.65\u00a0mm<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Pin Count<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">4 to 100+ (dual-row and multi-row extend range)<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">EPAD Stencil Coverage<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">50\u201375\u00a0% of EPAD area (65\u201375\u00a0% with encroached vias)<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Thermal Via Diameter<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">0.3\u20130.33\u00a0mm (plugged\/filled preferred; no thermal relief)<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Thermal Via Copper Plating<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Minimum 1\u00a0oz (35\u00a0\u00b5m) barrel copper<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Thermal Via Count<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">9\u201325 typical; minimum 8 for 36-pin; \u226516 for 6\u00d76\u00a0mm EPAD<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">\u03b8JC (high-power devices)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">1\u20135\u00a0\u00b0C\/W<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">\u03b8JA (JEDEC 4-layer board)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">20\u201360\u00a0\u00b0C\/W depending on package size and via count<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Max Void Area (IPC-A-610)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">\u226425\u00a0% of thermal pad area<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Recommended Solder Coverage<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">\u226590\u00a0% for optimum thermal performance<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Solder Paste Type<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Type 3 or Type 4, SAC305 (Sn\/Ag\/Cu), Low-Residue No-Clean<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Stencil Thickness<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">0.12\u20130.15\u00a0mm laser-cut stainless steel<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Stencil Aperture Ratio<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Area ratio &gt;0.66; Aspect ratio &gt;1.5<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Reflow Peak Temperature<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">235\u2013245\u00a0\u00b0C (SAC305 lead-free)<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Time Above Liquidus<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">30\u201390\u00a0seconds<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Preheat Ramp Rate<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">1\u20132\u00a0\u00b0C\/s<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Soak Stage<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">60\u2013120\u00a0s at 150\u2013180\u00a0\u00b0C<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Cooling Ramp Rate<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">2\u20134\u00a0\u00b0C\/s<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Inspection Method<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">X-ray (2D\/3D laminography) for void and bridging verification<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Moisture Sensitivity Level<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Per J-STD-020; typically MSL 3<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">Lead-Free Compliance<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"312\"><span data-font-family=\"Arial\">RoHS; REACH; SAC305 standard finish<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2><b><span data-font-family=\"Arial\">Customization and PCB Design Options<\/span><\/b><\/h2>\n<p><span data-font-family=\"Arial\">QFN PCB layout and assembly parameters are fully configurable within IPC\/JEDEC guidelines:<\/span><\/p>\n<ul>\n<li><span data-font-family=\"Arial\">Pad type (NSMD vs SMD): Non-Solder Mask Defined (NSMD) pads are preferred for perimeter signal lands \u2014 solder mask opening 60\u201370\u00a0\u00b5m larger than copper pad \u2014 enabling better solder joint reliability. SMD is used for the central EPAD to control paste registration.<\/span><\/li>\n<li><span data-font-family=\"Arial\">Thermal via type: Through-vias (0.3\u00a0mm, tented\/plugged), blind microvias, or a combination. Plugged or encroached vias prevent solder wicking and eliminate protrusions on the reverse board side.<\/span><\/li>\n<li><span data-font-family=\"Arial\">Stencil aperture pattern: Grid (rectangular windows), cross-hatch, or circular arrays \u2014 aperture pitch 1.0\u20131.5\u00a0mm, web thickness minimum 0.2\u20130.3\u00a0mm. Pattern is tuned to EPAD area and via configuration.<\/span><\/li>\n<li><span data-font-family=\"Arial\">EPAD size: PCB thermal land typically 1:1 with package EPAD. Some designs extend by 0.1\u20130.2\u00a0mm per side; overly large lands risk EPAD-to-signal-pad bridging.<\/span><\/li>\n<li><span data-font-family=\"Arial\">Via fill: Open vias (standard), tented (solder mask capped), plugged with non-conductive epoxy, or IPC Type VII copper-filled. Filled vias eliminate solder wicking at the cost of an additional process step.<\/span><\/li>\n<li><span data-font-family=\"Arial\">Signal routing under EPAD: Trace routing between EPAD and perimeter pads must be avoided; trace crowns and via edges exposed by broken solder mask can create intermittent shorts during thermal cycling.<\/span><\/li>\n<li><span data-font-family=\"Arial\">Rework clearance: Pad extensions of 0.1\u20130.2\u00a0mm beyond the package outline on the outer edge of signal pads allow visual solder fillet inspection and facilitate rework access.<\/span><\/li>\n<\/ul>\n<h2><b><span data-font-family=\"Arial\">Application Scenarios<\/span><\/b><\/h2>\n<h4><b><span data-font-family=\"Arial\">Consumer Electronics &amp; Mobile (Smartphones, Wearables)<\/span><\/b><\/h4>\n<p><span data-font-family=\"Arial\">QFN packages house power management ICs, RF transceivers, and audio codecs in space-constrained designs. The small 2\u00d72 to 4\u00d74\u00a0mm body fits within dense BGA escape routes, while the EPAD ensures the PMIC stays within junction temperature limits under heavy load.<\/span><\/p>\n<h4><b><span data-font-family=\"Arial\">Automotive Electronics (ADAS, EV Powertrains)<\/span><\/b><\/h4>\n<p><span data-font-family=\"Arial\">DC-DC converters, gate drivers, and CAN\/LIN transceivers in automotive ECUs require AEC-Q100 qualified QFN ICs. The direct EPAD-to-copper thermal path meets continuous high-ambient-temperature demands (\u221240\u00a0\u00b0C to +150\u00a0\u00b0C) of underhood environments per IPC-6012 EA.<\/span><\/p>\n<h4><b><span data-font-family=\"Arial\">Telecommunications &amp; RF Infrastructure<\/span><\/b><\/h4>\n<p><span data-font-family=\"Arial\">PA stages, LNA modules, and VCOs in 5G base stations and microwave backhaul equipment demand the sub-3\u00a0nH lead inductance that QFN delivers. RF QFN packages are optimized for 50-ohm impedance matching with ground-plane copper directly beneath the EPAD.<\/span><\/p>\n<h4><b><span data-font-family=\"Arial\">Industrial Automation &amp; Motor Control<\/span><\/b><\/h4>\n<p><span data-font-family=\"Arial\">Motor driver ICs and isolated gate drivers in VFDs and servo systems dissipate several watts continuously. QFN thermal pads soldered to 2\u00a0oz copper planes with 16+ thermal vias support junction temperatures within safe operating limits at ambient temperatures up to 85\u00a0\u00b0C.<\/span><\/p>\n<h4><b><span data-font-family=\"Arial\">Medical Devices &amp; Instrumentation<\/span><\/b><\/h4>\n<p><span data-font-family=\"Arial\">Low-power sensor AFEs and signal conditioning ICs in patient monitoring, ultrasound, and diagnostics use QFN for the combination of small footprint, low noise (short lead inductance), and reliable thermal management per IPC-6012 EM Class 3.<\/span><\/p>\n<h4><b><span data-font-family=\"Arial\">Power Management &amp; Renewable Energy<\/span><\/b><\/h4>\n<p><span data-font-family=\"Arial\">MPPT controllers and synchronous rectifiers in solar inverters and BMS routinely dissipate 1\u20135\u00a0W in QFN packages. The EPAD thermal path with thermal vias to an internal copper plane achieves \u03b8JA below 30\u00a0\u00b0C\/W on a 4-layer board, keeping junction temperatures below 125\u00a0\u00b0C at full load.<\/span><\/p>\n<h2><b><span data-font-family=\"Arial\">Package Comparison: QFN vs. QFP vs. BGA<\/span><\/b><\/h2>\n<table>\n<tbody>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><b><span data-font-family=\"Arial\">Attribute<\/span><\/b><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><b><span data-font-family=\"Arial\">QFN (Quad Flat No-Lead)<\/span><\/b><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><b><span data-font-family=\"Arial\">QFP (Quad Flat Package)<\/span><\/b><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><b><span data-font-family=\"Arial\">BGA (Ball Grid Array)<\/span><\/b><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Lead Type<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Leadless bottom pads<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Gull-wing perimeter leads<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Solder ball grid on underside<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Footprint (same pin count)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Smallest<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Larger (~30\u201350\u00a0% more area)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Similar for low pin counts<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">\u03b8JC (with EPAD)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">1\u20135\u00a0\u00b0C\/W (excellent)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">10\u201330\u00a0\u00b0C\/W (moderate)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">5\u201320\u00a0\u00b0C\/W (good with thermal ball)<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Lead Inductance<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">1\u20133\u00a0nH (very low)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">5\u201310\u00a0nH (moderate)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">1\u20135\u00a0nH (low)<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Pin Count<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">4\u2013100+<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">32\u2013256<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">100\u20132500+<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Solder Joint Inspection<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">X-ray only<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Visual (gull-wing fillet visible)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">X-ray only<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Rework Difficulty<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">High (requires specialist station)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Low (iron accessible)<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">High (BGA rework station)<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Assembly Cost<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Moderate<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Low<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Higher (ball attach process)<\/span><\/td>\n<\/tr>\n<tr>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Best Application<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Power mgmt, RF, medium I\/O<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">Legacy, inspection-critical<\/span><\/td>\n<td colspan=\"1\" rowspan=\"1\" width=\"156\"><span data-font-family=\"Arial\">High I\/O, fine-pitch processors<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2><b><span data-font-family=\"Arial\">Frequently Asked Questions<\/span><\/b><\/h2>\n<h3><b><span data-font-family=\"Arial\">What is the correct stencil aperture design for a QFN thermal pad?<\/span><\/b><\/h3>\n<p><span data-font-family=\"Arial\">A 1:1 stencil opening deposits too much solder paste on the EPAD, causing the package to float or skate during reflow and producing electrical opens on perimeter signal pads. The recommended coverage is 50\u201375\u00a0% of the EPAD area using a windowed or cross-hatch aperture pattern with a minimum web of 0.2\u20130.3\u00a0mm between openings. This web creates gas escape channels that allow flux volatiles to outgas during the reflow soak stage, reducing void formation beneath the pad. For designs using encroached vias, 70\u201375\u00a0% coverage is recommended per Microchip AN18.15; for through-vias, 65\u00a0% is the typical target.<\/span><\/p>\n<h3><b><span data-font-family=\"Arial\">How many thermal vias should I place under the QFN EPAD, and what size?<\/span><\/b><\/h3>\n<p><span data-font-family=\"Arial\">Via diameter of 0.3\u20130.33\u00a0mm with at least 1\u00a0oz (35\u00a0\u00b5m) copper barrel plating is the industry standard. Solid connections between vias and the thermal pad are mandatory \u2014 thermal relief spokes must not be used, as they restrict thermal conduction. The minimum via count is 8 for a 36-pin device; for 6\u00d76\u00a0mm EPADs, at least 16 vias are required. Thermal improvement becomes asymptotic above approximately 25 vias, so practical designs target 9\u201325 in a regular grid. Tented, plugged, or copper-filled vias prevent solder wicking that causes voids and underside solder protrusions.<\/span><\/p>\n<h3><b><span data-font-family=\"Arial\">How do I verify solder joint quality under a QFN after reflow?<\/span><\/b><\/h3>\n<p><span data-font-family=\"Arial\">Visual inspection cannot assess QFN solder joints because they are entirely hidden beneath the package. Automated X-ray inspection (2D or 3D laminography) is the only production-viable method for verifying EPAD void percentage and detecting bridging between the thermal pad and adjacent signal lands. IPC-A-610 limits voiding to a maximum of 25\u00a0% of the thermal pad area for production acceptance. For high-reliability Class\u00a03 applications, cross-sectional X-ray or destructive cross-section analysis is used to confirm via barrel fill and solder joint thickness.<\/span><\/p>\n<h3><b><span data-font-family=\"Arial\">What causes QFN thermal pad voiding and how do I reduce it?<\/span><\/b><\/h3>\n<p><span data-font-family=\"Arial\">The primary cause is flux outgassing during reflow: volatile compounds in solder paste generate gas that becomes trapped under the large pad area. Secondary causes include excessive paste volume (1:1 stencil opening), aggressive reflow ramp rates that prevent gas escape before solder solidifies, and open via holes that allow solder to wick away. Mitigation: subdivided stencil apertures at 50\u201375\u00a0% coverage, slow preheat ramp of 1\u20132\u00a0\u00b0C\/s, extended soak at 150\u2013180\u00a0\u00b0C for 60\u2013120\u00a0s, plugged or copper-filled thermal vias, and SAC305 Type\u00a03\/4 no-clean paste optimized for QFN assembly.<\/span><\/p>\n<h3><b><span data-font-family=\"Arial\">Can I route traces between the QFN EPAD and the perimeter signal pads?<\/span><\/b><\/h3>\n<p><span data-font-family=\"Arial\">Routing traces between the EPAD and the perimeter pads is strongly discouraged. Trace edges and via hole edges in this zone can be exposed through broken solder mask \u2014 particularly after thermal cycling during assembly \u2014 creating intermittent short-circuit paths between the EPAD (typically ground) and adjacent signal pads. Best practice is to keep this zone free of any routing, and to extend the EPAD perimeter solder mask to protect exposed copper edges. All inner-layer signal routing for the QFN should exit the package footprint outside the thermal pad boundary.<\/span><\/p>\n<h2><b><span data-font-family=\"Arial\">Conclusion<\/span><\/b><\/h2>\n<p><span data-font-family=\"Arial\">A well-executed QFN layout comes down to four fundamentals: thermal land sizing at 1:1 with the package EPAD, a via array of 9\u201325 solid-fill vias at \u00d80.3\u00a0mm without thermal relief spokes, a subdivided stencil aperture at 50\u201375\u00a0% EPAD coverage, and a controlled reflow profile with a 60\u2013120-second soak stage. Get these right and you will achieve solder coverage above 90\u00a0%, keep \u03b8JB well within safe limits, and pass X-ray inspection at first article.<\/span><\/p>\n<p><span data-font-family=\"Arial\">For any design pushing thermal or electrical limits \u2014 5G RF front-ends, EV gate drivers, high-density PMIC arrays \u2014 the QFN remains the strongest package choice in the SMT portfolio. The key is treating the thermal pad as a precision assembly target, not an afterthought.<\/span><\/p>\n<h2><b><span data-font-family=\"Arial\">Find What You Need on <a href=\"http:\/\/lcsc.com\">LCSC<\/a><\/span><\/b><\/h2>\n<p><span data-font-family=\"Arial\">LCSC Electronics stocks thousands of QFN-packaged ICs across every major category \u2014 power management, RF transceivers, microcontrollers, motor drivers, and more \u2014 from both global and Asian manufacturers at competitive prices. Whether you are prototyping a compact PMIC layout, sourcing AEC-Q100 qualified gate drivers for an automotive ECU, or looking for RF front-end modules with sub-3\u00a0nH lead inductance, LCSC\u2019s parametric search lets you filter by package type, body size, pin pitch, and temperature rating in seconds. Every listing includes the manufacturer datasheet with EPAD dimensions and recommended land pattern \u2014 exactly the data you need to finalize your PCB layout. With real-time stock visibility, competitive per-unit pricing that scales from prototype to production, and global shipping, LCSC is where engineers go to move from schematic to assembled board faster. Start your QFN component search at lcsc.com.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Takeaway Size the PCB thermal land 1:1 with the package EPAD (or +0.1\u20130.2\u00a0mm per side maximum). Use 9\u201325 thermal vias at \u00d80.3\u20130.33\u00a0mm with solid copper fill \u2014 no thermal relief spokes. Design stencil apertures to cover 50\u201375\u00a0% of EPAD area with a windowed or cross-hatch pattern. Target \u226590\u00a0% solder coverage beneath the pad; IPC-A-610 sets [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[176,175],"tags":[181,390],"class_list":["post-4271","post","type-post","status-publish","format-standard","hentry","category-pcb-smt-basics","category-pcb-smt","tag-pcb","tag-qfn"],"blocksy_meta":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>QFN PCB Layout Guide: Thermal Pad &amp; Solder Void Control Blog | LCSC Electronics<\/title>\n<meta name=\"description\" content=\"Optimize QFN thermal pad &amp; stencil design to prevent solder voids. Source QFN ICs with datasheets directly from LCSC.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"QFN PCB Layout Guide: Thermal Pad &amp; Solder Void Control Blog | LCSC Electronics\" \/>\n<meta property=\"og:description\" content=\"Optimize QFN thermal pad &amp; stencil design to prevent solder voids. Source QFN ICs with datasheets directly from LCSC.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog | LCSC Electronics\" \/>\n<meta property=\"article:published_time\" content=\"2026-06-24T08:42:13+00:00\" \/>\n<meta name=\"author\" content=\"LCSC Editor\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"LCSC Editor\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"12 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/qfn-pcb-layout-guide\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/qfn-pcb-layout-guide\\\/\"},\"author\":{\"name\":\"LCSC Editor\",\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/#\\\/schema\\\/person\\\/11d3b92d0208775e62d7f79a0da4e781\"},\"headline\":\"QFN PCB Layout Guide: Thermal Pad &#038; Solder Void Control\",\"datePublished\":\"2026-06-24T08:42:13+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/qfn-pcb-layout-guide\\\/\"},\"wordCount\":2466,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/#organization\"},\"keywords\":[\"PCB\",\"QFN\"],\"articleSection\":[\"- Basics\",\"PCB\\\/SMT\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/qfn-pcb-layout-guide\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/qfn-pcb-layout-guide\\\/\",\"url\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/qfn-pcb-layout-guide\\\/\",\"name\":\"QFN PCB Layout Guide: Thermal Pad & Solder Void Control Blog | LCSC Electronics\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/#website\"},\"datePublished\":\"2026-06-24T08:42:13+00:00\",\"description\":\"Optimize QFN thermal pad & stencil design to prevent solder voids. Source QFN ICs with datasheets directly from LCSC.\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/qfn-pcb-layout-guide\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/qfn-pcb-layout-guide\\\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/qfn-pcb-layout-guide\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"QFN PCB Layout Guide: Thermal Pad &#038; Solder Void Control\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/#website\",\"url\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/\",\"name\":\"Blog | LCSC Electronics\",\"description\":\"LCSC Electronics Blogs and News\",\"publisher\":{\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/#organization\",\"name\":\"Blog | LCSC Electronics\",\"url\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/blogs.lcsc.com\\\/wp-content\\\/uploads\\\/2023\\\/10\\\/logo.png\",\"contentUrl\":\"https:\\\/\\\/blogs.lcsc.com\\\/wp-content\\\/uploads\\\/2023\\\/10\\\/logo.png\",\"width\":939,\"height\":180,\"caption\":\"Blog | LCSC Electronics\"},\"image\":{\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/#\\\/schema\\\/logo\\\/image\\\/\"}},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/#\\\/schema\\\/person\\\/11d3b92d0208775e62d7f79a0da4e781\",\"name\":\"LCSC Editor\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/0c5d2ddc240c300192ecdc04c2d2f7914d4b02bd00ea81b32e98b698c49e357f?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/0c5d2ddc240c300192ecdc04c2d2f7914d4b02bd00ea81b32e98b698c49e357f?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/0c5d2ddc240c300192ecdc04c2d2f7914d4b02bd00ea81b32e98b698c49e357f?s=96&d=mm&r=g\",\"caption\":\"LCSC Editor\"},\"url\":\"https:\\\/\\\/blogs.lcsc.com\\\/blog\\\/author\\\/lcsc-editor\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"QFN PCB Layout Guide: Thermal Pad & Solder Void Control Blog | LCSC Electronics","description":"Optimize QFN thermal pad & stencil design to prevent solder voids. Source QFN ICs with datasheets directly from LCSC.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/","og_locale":"en_US","og_type":"article","og_title":"QFN PCB Layout Guide: Thermal Pad & Solder Void Control Blog | LCSC Electronics","og_description":"Optimize QFN thermal pad & stencil design to prevent solder voids. Source QFN ICs with datasheets directly from LCSC.","og_url":"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/","og_site_name":"Blog | LCSC Electronics","article_published_time":"2026-06-24T08:42:13+00:00","author":"LCSC Editor","twitter_card":"summary_large_image","twitter_misc":{"Written by":"LCSC Editor","Est. reading time":"12 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/#article","isPartOf":{"@id":"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/"},"author":{"name":"LCSC Editor","@id":"https:\/\/blogs.lcsc.com\/blog\/#\/schema\/person\/11d3b92d0208775e62d7f79a0da4e781"},"headline":"QFN PCB Layout Guide: Thermal Pad &#038; Solder Void Control","datePublished":"2026-06-24T08:42:13+00:00","mainEntityOfPage":{"@id":"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/"},"wordCount":2466,"commentCount":0,"publisher":{"@id":"https:\/\/blogs.lcsc.com\/blog\/#organization"},"keywords":["PCB","QFN"],"articleSection":["- Basics","PCB\/SMT"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/","url":"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/","name":"QFN PCB Layout Guide: Thermal Pad & Solder Void Control Blog | LCSC Electronics","isPartOf":{"@id":"https:\/\/blogs.lcsc.com\/blog\/#website"},"datePublished":"2026-06-24T08:42:13+00:00","description":"Optimize QFN thermal pad & stencil design to prevent solder voids. Source QFN ICs with datasheets directly from LCSC.","breadcrumb":{"@id":"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/blogs.lcsc.com\/blog\/qfn-pcb-layout-guide\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/blogs.lcsc.com\/blog\/"},{"@type":"ListItem","position":2,"name":"QFN PCB Layout Guide: Thermal Pad &#038; Solder Void Control"}]},{"@type":"WebSite","@id":"https:\/\/blogs.lcsc.com\/blog\/#website","url":"https:\/\/blogs.lcsc.com\/blog\/","name":"Blog | LCSC Electronics","description":"LCSC Electronics Blogs and News","publisher":{"@id":"https:\/\/blogs.lcsc.com\/blog\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/blogs.lcsc.com\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/blogs.lcsc.com\/blog\/#organization","name":"Blog | LCSC Electronics","url":"https:\/\/blogs.lcsc.com\/blog\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/blogs.lcsc.com\/blog\/#\/schema\/logo\/image\/","url":"https:\/\/blogs.lcsc.com\/wp-content\/uploads\/2023\/10\/logo.png","contentUrl":"https:\/\/blogs.lcsc.com\/wp-content\/uploads\/2023\/10\/logo.png","width":939,"height":180,"caption":"Blog | LCSC Electronics"},"image":{"@id":"https:\/\/blogs.lcsc.com\/blog\/#\/schema\/logo\/image\/"}},{"@type":"Person","@id":"https:\/\/blogs.lcsc.com\/blog\/#\/schema\/person\/11d3b92d0208775e62d7f79a0da4e781","name":"LCSC Editor","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/0c5d2ddc240c300192ecdc04c2d2f7914d4b02bd00ea81b32e98b698c49e357f?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/0c5d2ddc240c300192ecdc04c2d2f7914d4b02bd00ea81b32e98b698c49e357f?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/0c5d2ddc240c300192ecdc04c2d2f7914d4b02bd00ea81b32e98b698c49e357f?s=96&d=mm&r=g","caption":"LCSC Editor"},"url":"https:\/\/blogs.lcsc.com\/blog\/author\/lcsc-editor\/"}]}},"_links":{"self":[{"href":"https:\/\/blogs.lcsc.com\/blog\/wp-json\/wp\/v2\/posts\/4271","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.lcsc.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.lcsc.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.lcsc.com\/blog\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.lcsc.com\/blog\/wp-json\/wp\/v2\/comments?post=4271"}],"version-history":[{"count":1,"href":"https:\/\/blogs.lcsc.com\/blog\/wp-json\/wp\/v2\/posts\/4271\/revisions"}],"predecessor-version":[{"id":4272,"href":"https:\/\/blogs.lcsc.com\/blog\/wp-json\/wp\/v2\/posts\/4271\/revisions\/4272"}],"wp:attachment":[{"href":"https:\/\/blogs.lcsc.com\/blog\/wp-json\/wp\/v2\/media?parent=4271"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.lcsc.com\/blog\/wp-json\/wp\/v2\/categories?post=4271"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.lcsc.com\/blog\/wp-json\/wp\/v2\/tags?post=4271"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}