onsemi GaNEXUS Closes the AI Server Power Gap: 60% Smaller PSUs and the BOM Changes That Come With Them
onsemi GaNEXUS Closes the AI Server Power Gap: 60% Smaller PSUs and the BOM Changes That Come With Them
By Procurement Priya · icboms supply-chain desk · data through August 25, 2026
In June 2026, onsemi closed a product gap that had been open for two years: a gallium nitride power semiconductor portfolio branded GaNEXUS, purpose-built for AI datacenter and high-voltage power conversion applications. By August, the company confirmed that the portfolio had completed its AI power stack integration and that its datacenter revenue was on a trajectory to double year-over-year. The timing is not coincidental. AI server rack designs are pushing power density to a point where traditional silicon MOSFETs cannot deliver the efficiency and form factor that hyperscalers demand. The PSUs inside an AI server rack that previously occupied 3U of rack space can, with GaN, be redesigned to fit in 1.2U. That 60% footprint reduction is not an engineering nice-to-have — it determines whether a rack holds 16 GPUs or 20.
This report covers what the onsemi GaNEXUS launch means for AI server power supply procurement, how the GaN vs. SiC vs. superjunction MOSFET choice breaks down for 48V intermediate bus converters, what it means for the BOM of new AI server platforms being qualified today, and the specific onsemi optocoupler and isolation components — in catalog and available for RFQ — that support the signal isolation layer in GaN-based power stages.
询价 · 交期 · MOQ 可询价，在售品批量供应
The GaNEXUS Portfolio and What It Actually Covers
The GaNEXUS launch in June 2026 was onsemi's third major power semiconductor product line addition in 18 months, following expansions in SiC and superjunction MOSFETs. The GaN portfolio is specifically positioned for the 48V-to-400V range that dominates the intermediate bus converter stage in AI server power supplies. Below 48V, GaN is unchallenged on efficiency. Above 200V, SiC takes over. The 48V-to-200V zone is where GaN competes directly with superjunction MOSFETs — and where the efficiency advantage of GaN translates to meaningful thermal and size benefits in a server rack.
onsemi's own announcement quantified the advantage: GaN-based power stages achieve equivalent performance to silicon MOSFETs while reducing the power conversion stage footprint by 60%. For a hyperscaler running 10,000 server racks, a 60% reduction in the PSU footprint per rack frees enough rack space for two additional GPU servers per rack — at current GPU server margins, that is hundreds of millions of dollars in additional revenue per year. That arithmetic is why the Nvidia partnership, expanded in June 2026, matters for procurement teams: if the reference design shifts to GaN, every ODM that follows that reference design needs GaN parts on the BOM.
交期和供货方面，GaNEXUS 目前处于产量爬坡阶段，AI服务器OEM客户通过 Nvidia 联盟获得优先分配，其他买家可通过授权分销渠道询价，确认交期和MOQ。
GaN vs. SiC vs. Superjunction MOSFETs: Where Each Material Fits in an AI Server PSU
A modern AI server PSU typically has three power conversion stages, each at a different voltage and each best served by a different semiconductor material:
The 48V intermediate bus converter — this is where GaN has the clearest advantage. At switching frequencies of 500kHz to 2MHz, GaN's low gate charge and near-zero switching losses translate to high efficiency in a small magnetic footprint. The 48V-to-12V buck converter that supplies the GPU board is the primary target application for GaN in AI servers. onsemi's GaNEXUS devices are targeting this stage. Lead times for engineering samples and initial production quantities are available through franchise distribution — 询价确认交期。
The 800V power factor correction stage — SiC is the established choice here. The 800V bus that runs across an AI server rack's power shelf is too high for GaN in current production technology and well within SiC's sweet spot. onsemi's SiC portfolio covers this stage, and the competitive suppliers — Wolfspeed, Infineon, Rohm — are all in various stages of expanding SiC capacity. SiC availability for 1200V automotive and industrial SKUs is improving but lead times for some automotive-qualified parts remain at 40-plus weeks. For non-automotive AI server SiC applications, the picture is better but not easy.
The 12V point-of-load converters — superjunction MOSFETs remain the cost-effective choice for the low-voltage, high-current POL converters that sit inches from the GPU and CPU. Infineon's CoolMOS series and onsemi's own SJMOS family occupy this space. These parts are broadly available, competitively priced, and have lead times measured in weeks rather than months. For new AI server designs, the POL stage is the least supply-constrained part of the power BOM — but it is also the stage where thermal design matters most, and GaN's efficiency advantage is beginning to reach down into this voltage range in cutting-edge designs.
供货方面，这三个材料区域各自有不同的供应商生态和交期，采购团队应分别跟踪，而不是假设一个「功率半导体」类别能一站式覆盖。
Signal Isolation in GaN Power Stages: onsemi Optocouplers in Catalog
GaN power stages at 500kHz-plus switching frequencies require isolated gate drivers and digital isolators to separate the PWM controller from the high dv/dt switching node. The optocoupler that isolates the gate drive signal from the power switch must maintain common-mode transient immunity above 50kV/μs while adding less than 100ns of propagation delay — these are not relaxed specifications for a GaN converter operating at 1MHz switching.
onsemi's FOD817 is a phototransistor optocoupler with 5,000Vrms isolation rating, propagation delay under 80ns, and common-mode immunity rated at 50kV/μs. It is in the ICBOMS catalog — available for 询价 with MOQ 可按批量洽购 — and commonly specified in power supply designs that require reinforced isolation between the primary-side controller and the secondary-side GaN switches. The FOD817 is the starting point for power stage isolation in GaN-based 48V-to-12V converters.
ICBOMS also carries additional onsemi optocoupler families that support the GaN power stage signal chain: the CNY174 dual optocoupler for dual-forward and push-pull topologies common in interleaved converter designs; the 4N35 general-purpose optocoupler for gate drive isolation where propagation delay budget is tighter; and the FOD2741, a higher-current-transfer-ratio phototransistor optocoupler specified in designs where the optocoupler must actively drive the GaN gate rather than merely pass the PWM signal through. All four parts are in catalog and available for inquiry through product pages or the sourcing desk.
What Buyers Should Do Now
GaN is not a future technology for AI server power supplies — it is a 2026 procurement decision. The GaNEXUS launch and the August confirmation that datacenter revenue is doubling are the market signal that the technology has crossed the threshold from engineering exercise to production material.
询价 on GaNEXUS allocation and lead times now, before the volume ramp creates allocation competition. The Nvidia alliance gives preferred customers allocation access; other buyers go through franchise distribution. Confirming the supply path in Q3 2026 is the right timing for 2027 production starts.
Qualify the GaN power stage BOM alongside the silicon baseline. A GaN redesign of the 48V intermediate bus converter requires a full thermal and efficiency recharacterization — that qualification cycle is 12–20 weeks for a server platform that is already in system-level debug. Teams that start the GaN qualification after the current silicon BOM is finalized will add months to their schedule.
Source the isolation layer separately. The FOD817, CNY174, 4N35, and FOD2741 are in catalog, available for 批量采购, with MOQ that supports both engineering qualification and production ramp. The isolation components are not the long-lead items in a GaN power stage — the GaN switches are — but they should be on the BOM and ordered alongside the switches, not as an afterthought.
Track all three material zones simultaneously. A GaN-based AI server PSU typically has GaN in the 48V bus converter, SiC in the 800V PFC stage, and superjunction MOSFETs in the POL converters. Supply tightness in any one of those three zones delays the PSU delivery. Procurement teams that are only watching the headline GaN story will miss the real constraint if SiC availability tightens in Q4 2026.
ICBOMS supports the optocoupler layer of GaN-based AI server power supplies through the onsemi FOD817 and related families. For buyers working on GaN power stage designs and needing the signal isolation component layer confirmed or sourced, the product pages and RFQ channel are available. The GaN transition for AI datacenter power is not theoretical. It is the procurement reality of Q4 2026.
Data cutoff: August 25, 2026. Sources: GlobeNewswire (June 9, 2026); GlobeNewswire (August 4, 2026); TheLEC.net (June 2, 2026); Stock Titan (June 9, 2026). Treat all figures as directional planning data, not quotes. Verify lead times and allocation status with your franchised distributor.