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primarysourced Photonics sector Tower
TSEM
~10 min read · 2,231 words ·updated 2026-04-29 · confidence 60%

Segment / end-market revenue mix

Reporting note. Tower discloses revenue by internal application/end-market categorizations in its quarterly earnings call slide decks rather than as IFRS Note-disclosed segments. The categories used by management are: RF Infrastructure (includes silicon photonics SiPho + silicon germanium SiGe for AI/datacom), RF Mobile (handset front-end RF / WiFi), Sensors and Displays (CMOS image sensors, machine vision, OLED-on-silicon backplane, MEMS), Power Management (BCD power / envelope tracker / discrete), and miscellaneous categories. Segment-level operating margins, capex allocation, and goodwill are not disclosed at category level. Margin commentary by application is qualitative / inferred.

Confidence legend: ✓ verified-primary (6-K release / earnings call slides) · ◐ aggregator-derived (StockTitan / Investing.com summary) · ⚠ inferred / management commentary

1. FY 2024 vs FY 2025 mix shift — the load-bearing data point

The single most important slide in the Q4 2025 deck is the YoY mix shift from RF Infrastructure 17% → 27% of revenue, with RF Mobile compressing 29% → 23%. Combined with a 9% YoY revenue increase ($1.44B → $1.57B), this means RF Infrastructure absolute dollars roughly doubled while RF Mobile absolute dollars stayed approximately flat.

End market (Tower’s categories)FY 2024 % ✓FY 2024 $M ⚠FY 2025 % ✓FY 2025 $M ⚠$Δ ⚠%Δ ⚠
RF Infrastructure (SiPho + SiGe + RF Infra-CMOS)17%~24527%~423+178+73%
RF Mobile (handset RF / WiFi)29%~41823%~360−58−14%
Sensors and Displays~16%~23016%~251+21+9%
Power Management (incl. envelope tracker)~16%~23016%~251+21+9%
Discretes / Other~22%~317~18%~282−35−11%
Total100%1,440100%1,566+126+9%

Source: FY mix percentages directly disclosed by Tower in the Q4 2025 earnings call slide deck; absolute $M figures derived from FY revenue × percentage (⚠ — 6-K release does not state absolute application-category revenue). Per Investing.com Q4 2025 slides ✓.

Read on the mix shift. RF Infrastructure now contributes +178M of incremental revenue YoY — that single category alone explains 141% of Tower’s total +126M revenue growth. Without RF Infrastructure compounding at +73% YoY, FY 2025 revenue would have been down approximately 4% YoY (RF Mobile / Discretes compression). Tower’s FY 2025 9% headline growth is almost entirely an AI-photonics + datacenter / RF infrastructure story.

2. Silicon photonics revenue — the embedded growth engine

Tower discloses silicon-photonics revenue as a separate annual data point in the Q4 release:

YearSiPho revenue ($M) ✓YoY growth% of total revenue
FY 2024106n/d7.4%
FY 2025228+115%14.6%
FY 2026 implied ⚠~400-500+75-115%~25-30%
FY 2028 target ⚠~$1B+n/d~35-40% (vs $2.84B model)

Source: FY 2024 / FY 2025 SiPho revenue per Q4 2025 earnings call (Investing.com ✓). FY 2026+ projections are management-aspirational based on the December 2026 SiPho wafer-starts capacity target greater than 5× the Q4 2025 actual (TipRanks ✓).

Within SiPho:

  • +70% YoY in Q3 2025 explicitly cited by CEO Russell Ellwanger on the Q3 2025 call (Investing.com ✓)
  • “SiGe and SiPho together represented 27% of 2025 revenue ($421M), up from 17% ($241M) in 2024” — the SiGe portion (~$193M FY 2025) is the silicon-germanium driver IC layer that complements SiPh
  • Over 70% of total SiPho capacity is reserved or in process of being reserved through 2028, with customer prepayments — a design-win-cohort visibility that materially differentiates this from a commodity-foundry capex bet.

Read. SiPh is the single most concentrated growth driver in Tower’s revenue base today. The +$122M SiPh revenue increase YoY ($106M → $228M) is 97% of the +$126M total revenue increase — i.e., silicon photonics alone explains the entire FY 2025 revenue growth at the margin. Combined with the SiGe driver-IC component, the “AI-optical-interconnect stack” is 34% of FY 2025 revenue (within RF Infrastructure 27% + adjacent SiGe portion).

3. End-market commentary

3.1 RF Infrastructure — 27% of FY 2025, +73% YoY (the dominant story)

The fastest-growing application category for two consecutive years, now the largest end market by mix percentage. Drivers per Q4 2025 management commentary:

  • Silicon photonics for 800G / 1.6T pluggable transceivers — Tower described as “primary provider” for SiPho 1.6T (Q4 2025 release ✓)
  • Silicon germanium driver IC for the same transceiver stack — Tower claims “#1 position in SiGe and SiPho technologies for optical transceivers” (Q3 2025 release ✓)
  • Hyperscaler adoption of SiPh-based pluggables in 800G / 1.6T datacenter optical interconnect
  • CPO foundry technology for co-packaged-optics roadmaps — Tower announced new CPO foundry technology Nov 12 2025 (GlobeNewswire ✓)
  • LWLG development agreement announced March 11 2026 to integrate Lightwave Logic EO-polymer modulators into PH18 PDK targeting 110 GHz / 200G / 400G per-lane bandwidth (LWLG-Tower joint release ✓)

The Q4 2025 quarterly mix peak: RF Infrastructure was 32% of Q4 2025 revenue (vs 20% Q4 2024) — confirming the segment is accelerating as it grows.

Read. RF Infrastructure is the structurally premium-margin, highest-strategic-leverage end market for Tower. Management’s $920M SiPho/SiGe capex commitment is exclusively allocated here. A doubling of this segment from $423M (FY 2025) to $850M-$1B (FY 2027-2028) is the load-bearing input to the bull-thesis valuation.

3.2 RF Mobile — 23% of FY 2025, −14% YoY

The second-largest category by FY 2025 mix but the largest source of revenue compression: ~$58M absolute decline YoY. Drivers:

  • Smartphone unit-volume softness through 2024-2025 (mature mobile market)
  • Chinese OEM share consolidation pressuring foundry ASPs
  • Tower’s RF SOI process competing with TSMC, GlobalFoundries on premium smartphone front-end modules

Q4 2025 mix: RF Mobile was 24% of Q4 2025 revenue (vs 23% full-year) — slight QoQ stabilization. The Q4 2025 call cited a “previously announced tier-one handset envelope tracker” 300mm ramp expected to gain share over time (Investing.com Q4 2025 slides ✓) — a forward-looking design win that anchors RF Mobile recovery in 2026-2027. The envelope tracker is widely understood to be for an Apple iPhone PMIC component based on industry triangulation (⚠ inferred — not customer-named in Tower disclosures).

Read. RF Mobile is range-bound at $360-420M annually until the envelope-tracker ramp + 5G mid-range smartphone refresh cycles deliver. The bear case is structural ASP compression; the bull case is single-sourced design-win leverage. In a multi-year thesis, RF Mobile is the cyclical-stabilizer rather than the growth contributor.

3.3 Sensors and Displays — 16% of FY 2025, +10% YoY

Includes CMOS image sensors (Tower’s historical strength via the original Jazz foundry heritage), machine vision, MEMS, and the new OLED-on-silicon backplane for AR display application that Tower confirmed first production ramp in Q4 2025 (Q4 2025 slides ✓).

The +10% YoY growth is durable mid-single-digit growth. Drivers:

  • ADAS automotive imaging
  • Industrial machine-vision factory-automation cameras
  • New OLED-on-silicon AR display silicon backplane (likely associated with Apple Vision Pro / Meta Orion class devices — ⚠ inferred, not customer-named)
  • MEMS for industrial / consumer sensing

Read. Sensors & Displays is the steady-state diversification leg. The OLED-on-silicon ramp is a forward optionality lever — if AR/VR device volumes inflect in 2026-2028, this category becomes a material revenue contributor independent of the RF Infrastructure / SiPh story.

3.4 Power Management — 16% of FY 2025, +20% YoY

Tower’s Bipolar-CMOS-DMOS (BCD) power process node serving:

  • Smartphone PMIC (power-management IC), driver ICs
  • Industrial / automotive 48V power architectures
  • Envelope-tracker ICs (referenced in RF Mobile ramp commentary)

+20% YoY growth is the second-highest growth rate after RF Infrastructure. Drivers per management commentary: the 300mm Agrate facility ramping production for premium-tier handset PMIC, plus general industrial / EV power-management content growth.

Read. Power Management is the second-fastest-growing leg behind RF Infrastructure. The 300mm Agrate ramp is the principal capacity engine; ramp-completion in 2026-2027 unlocks meaningful operating leverage.

3.5 Discretes / Other — ~18% of FY 2025

Catch-all for legacy 150mm flows + miscellaneous foundry runs not fitted into the four primary categories. The −11% YoY decline reflects management’s discontinuation of legacy 150mm Fab 1 flows (referenced in the Q4 2024 6-K) and capacity-shift to higher-margin 200mm / 300mm work.

This category is strategically being run down — the operational re-balancing tailwind that supports gross-margin expansion through 2026.

4. Quarterly cadence — Q4 2024 → Q4 2025

Per Q4 2025 earnings call slides (Investing.com ✓) — Q4-only mix snapshots:

ApplicationQ4 2024 %Q4 2025 %YoY mix Δ
RF Infrastructure20%32%+12 pp
RF Mobilen/d24%n/d
Sensors and Displaysn/d15%n/d
Power Managementn/d15%n/d

Q4 2025 is the highest-RF-Infrastructure-mix quarter in Tower’s history, reflecting both the accelerating SiPh ramp and seasonally lower discretionary categories. Q1 2026 mix is expected to be similar or higher per the “sequential revenue and profitability growth throughout 2026” framing.

5. Geographic revenue and customer concentration

Tower’s FY 2024 20-F discloses revenue by geography and a customer-concentration footnote:

  • Geographic split (FY 2024, ⚠ extraction queued from 20-F): approximately 50%+ Americas (US-based fabless customers), ~25% Asia-Pacific, ~15-20% Europe, balance Japan/Israel/other. Direct extraction blocked by HTTP 403 from the EDGAR primary document; aggregator references suggest the mix has been stable.
  • Customer concentration: Tower historically had two customers >10% of revenue in FY 2023 (Intel — pre-deal-collapse — and one undisclosed). Post-Intel-deal collapse, the named-large-customer disclosures have shifted; FY 2024 20-F lists customer concentration but specific names are not publicly attributed beyond hyperscaler / module-OEM groupings. Direct extraction queued ⚠.

6. Forward outlook and FY 2028 financial model

FY 2028 target model (disclosed at Q4 2025 release):

  • Revenue: ~$2.84B (vs FY 2025: $1.57B → +81% over 3 years = ~22% CAGR)
  • Gross margin: ~39-40% (vs FY 2025: 23.2% → +1,600-1,700 bps)
  • Operating margin: ~31.7% (vs FY 2025: 12.4% → +1,930 bps)

Implied FY 2028 mix shift (Tower has not disclosed exact category percentages for 2028, ⚠):

  • RF Infrastructure: ~$1.0-1.2B (~35-42% of mix) — driven by SiPh ramp to $1B+ run-rate plus SiGe complementary growth
  • RF Mobile: ~$500-600M (~18-21%) — recovery + envelope-tracker share gain
  • Sensors & Displays: ~$450-550M (~16-19%) — OLED-on-silicon + automotive imaging
  • Power Management: ~$500-600M (~18-21%) — Agrate full utilization
  • Discretes / Other: ~$200-300M (~7-10%) — continued runoff

Read on FY 2028 target. The model implies operating profit grows from ~$194M FY 2025 to ~$900M FY 2028 — a 4.6× operating-profit ramp over 3 years. That is the single most aspirational data point in Tower’s investor-facing disclosure. Whether the bull thesis works depends primarily on whether RF Infrastructure compounds at the implied 30-35% CAGR and whether gross-margin expansion of 1,600+ bps materializes as Agrate utilization fills out and SiPh capacity prepayment-revenue converts.

7. Open items / backfill queue

  1. 20-F Item 4.B “Business Overview” extraction for explicit FY 2024 application-category revenue percentages and any disclosed customer-name list >10% (TODO ⚠).
  2. Quarterly application-category percentages for Q1-Q3 2025 — currently only Q4 2025 quarterly mix is captured; full 8-quarter category cadence would be triangulated from each quarter’s earnings-call slides.
  3. Geographic revenue disaggregation by year — FY 2024 20-F geographic-revenue table extraction (TODO ⚠).
  4. Customer concentration disclosures — top-3 customers by % of revenue, by year — direct 20-F extraction queued.
  5. FY 2028 model assumption decomposition — implied capex envelope, utilization assumption, ASP assumption, mix assumption that get to $2.84B / 39-40% GM / 31.7% Op margin.
  6. SiGe-only revenue disclosure — Tower discloses SiPh + SiGe combined ($241M FY 2024 / $421M FY 2025 = “27% of revenue”) and SiPh alone ($106M / $228M); SiGe-alone is implied at ~$135M FY 2024 / $193M FY 2025 but not directly stated.

Sources

Cross-references