Littelfuse FlatSuppressX™ TP5.0SMD-FL vs AMSEMI 5.0SMDJ-N: Foldback TVS Comparison
One-line takeaway: the Littelfuse FlatSuppressX™ TP5.0SMD-FL (July 2026) put low-clamping / foldback TVS in the spotlight. The AMSEMI (Anhui Anmei Semiconductor) 5.0SMDJ-N series is a domestic low-clamping option in the same package and power class: at the four overlapping voltage grades the clamping-voltage difference is within ±3V / ±3%, and voltage coverage spans 24–100V in 23 grades (the Littelfuse FL series currently has 4), so it can be evaluated directly as a pin-to-pin replacement.
I. Littelfuse Launch Highlights (Quoted)
The following is quoted from the Littelfuse product page, datasheet and Mouser new-product coverage (July 2026); links are listed under Sources:
- FlatSuppressX™ technology: an advanced foldback I-V characteristic that maintains a near-constant, very low clamping voltage during fast transients and high-energy surges while avoiding latch-up;
- Positioned for 48V automotive: designed for next-generation 48V systems compliant with ISO 21780 — typical applications include battery disconnect units (BDU), zonal control units (ZCU), electric power steering (EPS), DC/DC converters and PTC heaters;
- Core benefit: lower clamping → downstream MOSFETs and power ICs with lower rated voltage → optimized BOM cost;
- Key specifications: 5000W peak pulse power (10/1000μs), AEC-Q101 qualified, DO-214AB (SMC) package, typical response time <1ps, ESD ±30kV (air/contact), RθJL 15°C/W, RθJA 75°C/W, plus a companion 1kW version TP1KSMB-FL (SMB package).
The message from the Littelfuse launch is clear: low-clamping / foldback is the next mainstream TVS form for high-voltage automotive and energy-storage power architectures — exactly the direction the AMSEMI -N series targets.
II. Grade-by-Grade Comparison: TP5.0SMD-FL vs AMSEMI 5.0SMDJ-N
Both are DO-214AB (SMC), 5000W (10/1000μs), bidirectional. Clamping voltage (Vc@Ipp, 10/1000μs waveform) compared grade by grade on the four grades Littelfuse has released:
| VR Working Voltage | Littelfuse Part | Littelfuse Vc | Littelfuse Ipp | AMSEMI Part | AMSEMI Vc | AMSEMI Ipp | Vc Difference |
|---|---|---|---|---|---|---|---|
| 54V | TP5.0SMD54CA-FL | 68.5V | 57.5A | 5.0SMDJ54CA-N | 69.6V | 57.5A | +1.1V (+1.6%) |
| 58V | TP5.0SMD58CA-FL | 72.4V | 53.5A | 5.0SMDJ58CA-N | 74.8V | 53.5A | +2.4V (+3.3%) |
| 60V | TP5.0SMD60CA-FL | 77.7V | 51.6A | 5.0SMDJ60CA-N | 77.4V | 51.7A | −0.3V (−0.4%) |
| 64V | TP5.0SMD64CA-FL | 80.5V | 48.4A | 5.0SMDJ64CA-N | 82.4V | 48.6A | +1.9V (+2.4%) |
Data sources: Littelfuse product page (TP5.0SMD-FL series); AMSEMI datasheet Document No. 8060055 (Rev. 2026-04-23). At the 60V grade the AMSEMI part actually clamps lower; across all four grades the difference stays within ±3V — the same low-clamping level.
Full Specification Comparison
| Parameter | Littelfuse TP5.0SMD-FL | AMSEMI 5.0SMDJ**CA-N |
|---|---|---|
| Peak pulse power Pppm | 5000W (10/1000μs) | 5000W (10/1000μs) |
| Package | DO-214AB (SMC) | DO-214AB (SMC) |
| VR coverage | 54 / 58 / 60 / 64V (4 grades) | 24–100V (23 grades) |
| Directionality | Bidirectional | Bidirectional (unidirectional on request) |
| AEC-Q101 | ✔ | ✔ |
| ESD capability | ±30kV (air/contact) | ±30kV (air/contact) |
| Operating junction temperature TJ | −65 ~ +175°C | −55 ~ +150°C |
| Steady-state power PM | 6.5W (TL=50°C) | 6.5W (TL=75°C) |
| Thermal resistance RθJA | 75°C/W | 75°C/W |
| Environmental | RoHS, halogen-free | RoHS, halogen-free, UL94 V-0 |
Honest differences to note: the Littelfuse FL series is rated to a 175°C junction temperature (the AMSEMI -N series to 150°C) — evaluate against the actual mounting temperature for very hot environments such as near engine compartments. The AMSEMI -N steady-state 6.5W is rated at a TL=75°C lead temperature, a thermal condition closer to real SMD mounting.
III. Foldback vs Traditional: How Big Is the Gap
Using datasheet data from the same AMSEMI platform (54V grade, Vc@Ipp, 10/1000μs):
| Part | Type | Vc@Ipp | vs Traditional |
|---|---|---|---|
| 5.0SMDJ54CA | Traditional TVS | 87.1V | Baseline |
| 5.0SMDJ54CA-N | Foldback (low-clamping) | 69.6V | −17.5V (about −20%) |
| TP5.0SMD54CA-FL | Littelfuse foldback | 68.5V | −18.6V (about −21%) |
Same 5000W, same SMC package — the foldback series pushes the residual voltage at high surge current down by about 20%. That is the antidote to downstream damage despite TVS, and the quantified meaning of the Littelfuse claim of lower-rated downstream parts and optimized BOM. The conclusion holds at the 58V / 60V / 64V grades (traditional 93.6 / 96.8 / 103.0V → foldback 74.8 / 77.4 / 82.4V).
Convention reminder: the reduction varies with grade and comparison target. Littelfuse officially publishes 11%–15% for its -FB series; the AMSEMI -N series delivers 20.0%–20.1% across the 54/58/60/64/75V grades. Always quote the datasheet value for the specific grade rather than a single percentage for the whole series.
IV. AMSEMI Foldback (Low-Clamping) TVS Part-Number List
5.0SMDJ**CA-N Series (5000W · DO-214AB/SMC · VR 24–100V)
| Part Number | Marking Code | VR (V) | VBR min–max (V) | Vc@Ipp (V) | Ipp (A) |
|---|---|---|---|---|---|
| 5.0SMDJ24CA-N | 5NEZ | 24 | 26.7–29.5 | 31.1 | 129.0 |
| 5.0SMDJ26CA-N | 5NFE | 26 | 28.9–31.9 | 33.6 | 119.0 |
| 5.0SMDJ28CA-N | 5NFG | 28 | 31.1–34.4 | 36.3 | 110.0 |
| 5.0SMDJ30CA-N | 5NFK | 30 | 33.3–36.8 | 38.7 | 103.0 |
| 5.0SMDJ33CA-N | 5NFM | 33 | 36.7–40.6 | 42.6 | 93.9 |
| 5.0SMDJ36CA-N | 5NFP | 36 | 40.0–44.2 | 46.4 | 86.1 |
| 5.0SMDJ40CA-N | 5NFR | 40 | 44.4–49.1 | 51.6 | 77.6 |
| 5.0SMDJ43CA-N | 5NFT | 43 | 47.8–52.8 | 55.5 | 72.1 |
| 5.0SMDJ45CA-N | 5NFV | 45 | 50.0–55.3 | 58.1 | 68.8 |
| 5.0SMDJ48CA-N | 5NFX | 48 | 53.3–58.9 | 61.9 | 64.7 |
| 5.0SMDJ51CA-N | 5NFZ | 51 | 56.7–62.7 | 65.9 | 60.7 |
| 5.0SMDJ54CA-N | 5NGE | 54 | 60.0–66.3 | 69.6 | 57.5 |
| 5.0SMDJ58CA-N | 5NGG | 58 | 64.4–71.2 | 74.8 | 53.5 |
| 5.0SMDJ60CA-N | 5NGK | 60 | 66.7–73.7 | 77.4 | 51.7 |
| 5.0SMDJ64CA-N | 5NGM | 64 | 71.1–78.6 | 82.4 | 48.6 |
| 5.0SMDJ70CA-N | 5NGP | 70 | 77.8–86.0 | 90.4 | 44.3 |
| 5.0SMDJ75CA-N | 5NGR | 75 | 83.3–92.1 | 96.8 | 41.4 |
| 5.0SMDJ78CA-N | 5NGT | 78 | 86.7–95.8 | 100.8 | 39.7 |
| 5.0SMDJ80CA-N | 5NGS | 80 | 89.4–98.8 | 104.0 | 38.5 |
| 5.0SMDJ85CA-N | 5NGV | 85 | 94.4–104.0 | 110.0 | 36.5 |
| 5.0SMDJ90CA-N | 5NGX | 90 | 100.0–111.0 | 116.8 | 34.3 |
| 5.0SMDJ95CA-N | 5NGY | 95 | 106.0–118.0 | 124.8 | 32.0 |
| 5.0SMDJ100CA-N | 5NGZ | 100 | 111.0–123.0 | 129.6 | 30.9 |
SMDJ**CA-N Series (3000W · DO-214AB/SMC · VR 24–90V)
| Part Number | Marking Code | VR (V) | VBR min–max (V) | Vc@Ipp (V) | Ipp (A) |
|---|---|---|---|---|---|
| SMDJ24CA-N | NEZ | 24 | 26.7–29.5 | 31.1 | 77.1 |
| SMDJ48CA-N | NFX | 48 | 53.3–58.9 | 61.9 | 38.8 |
| SMDJ51CA-N | NFZ | 51 | 56.7–62.7 | 65.9 | 36.4 |
| SMDJ54CA-N | NGE | 54 | 60.0–66.3 | 69.6 | 34.4 |
| SMDJ58CA-N | NGG | 58 | 64.4–71.2 | 74.8 | 32.1 |
| SMDJ60CA-N | NGK | 60 | 66.7–73.7 | 77.4 | 31.0 |
| SMDJ64CA-N | NGM | 64 | 71.1–78.6 | 82.4 | 29.1 |
| SMDJ70CA-N | NGP | 70 | 77.8–86.0 | 90.4 | 26.5 |
| SMDJ75CA-N | NGR | 75 | 83.3–92.1 | 96.8 | 24.8 |
| SMDJ78CA-N | NGT | 78 | 86.7–95.8 | 100.8 | 23.8 |
| SMDJ80CA-N | NGS | 80 | 89.4–98.8 | 104.0 | 23.1 |
| SMDJ85CA-N | NGV | 85 | 94.4–104.0 | 110.0 | 21.9 |
| SMDJ90CA-N | NGX | 90 | 100.0–111.0 | 116.8 | 20.5 |
Both series are AEC-Q101 qualified with ESD ±30kV (air/contact), bidirectional as standard (the CA versions above; unidirectional versions available on request). Data from AMSEMI datasheets Document No. 8060055 / 8060084; complete datasheets are available from Intek Technology.
V. Why Choose the AMSEMI 5.0SMDJ-N
- Same low-clamping level: clamping difference within 3% at the four overlapping grades, even lower at 60V — replacement-evaluation risk is small;
- Much wider voltage coverage: 24–100V in 23 grades (the Littelfuse FL series currently 4) — common BMS, energy-storage and telecom-power grades like 24V / 36V / 48V / 70V / 80V / 100V are all covered;
- Package-compatible replacement: same DO-214AB (SMC), identical pads and layout — existing 5kW SMC layouts can swap parts directly for verification;
- Domestic supply-chain advantage: factory-direct supply, controllable sample and volume lead times, better cost — a fit for automotive, energy-storage and two-/three-wheeler projects that care about supply security;
- Complete automotive qualification: AEC-Q101 passed, halogen-free, RoHS, and clear marking rules for production-line verification.
VI. FAQ
Q1: Is there a domestic alternative to the Littelfuse FlatSuppressX™ TP5.0SMD-FL?
Yes. The AMSEMI 5.0SMDJ**CA-N series shares the package (DO-214AB) and the 5000W power class, with clamping-voltage differences within 3% at the 54/58/60/64V grades — a direct pin-to-pin replacement candidate, covering 24–100V in 23 grades.
Q2: How far apart are the clamping voltages exactly?
Comparing Vc@Ipp at the 10/1000μs waveform: 54V grade 68.5V vs 69.6V, 58V grade 72.4V vs 74.8V, 60V grade 77.7V vs 77.4V, 64V grade 80.5V vs 82.4V — within ±3V / ±3%, the same low-clamping level.
Q3: My system runs a 36V / 48V bus and the Littelfuse FL series has no matching grade — what now?
The AMSEMI -N series covers 24–100V, with ready parts at 36V, 48V, 51V, 70V and more (e.g. 5.0SMDJ36CA-N, 5.0SMDJ48CA-N). Send your working voltage and surge level to Intek Technology for a selection proposal and samples.
Q4: Does moving from a traditional 5.0SMDJ to the -N foldback series require a board redesign?
No — both use the DO-214AB package and the pad layout does not change. The VBR range matches the traditional parts, so parts can be swapped directly for surge verification; we recommend re-measuring residual voltage with the corporate-standard waveform to confirm the downstream margin.
Sources
- Littelfuse TP5.0SMD-FL series product page
- Littelfuse TP5.0SMD-FL series datasheet (PDF)
- Mouser new-product coverage: Littelfuse TP5.0SMD-FL FlatSuppressX TVS Diodes
- AMSEMI datasheets: 5.0SMDJ**CA-N series (Doc. 8060055), SMDJ**CA-N series (Doc. 8060084), standard 5.0SMDJ series (Doc. 8060014), AMSEMI website
Contact Us
For AMSEMI 5.0SMDJ-N foldback TVS datasheets or samples, or a replacement evaluation against your surge test standard, contact us. For more low-clamping TVS selection knowledge, see How to Select TVS for BMS Protection Boards and AMSEMI Foldback TVS: Full Series & Cross-Reference.
Shenzhen Intek Technology Co., Ltd — electronic components distributor and system solutions provider Tel / WeChat: 136-3264-8484 Address: 4F, Building 2, Jingwei Center, No. 309 Pingan Avenue, Pinghu Street, Longgang District, Shenzhen, China Web: www.intek.vip
8000 W tier: AMSEMI's highest power class is the 8.0SMDJ series (8000 W at 10/1000 us, DO-214AB/SMC), giving extra energy margin on the same SMC land pattern. This tier is likewise an -N foldback series (8.0SMDJCA-N**, Vrwm 48-90 V, 11 bidirectional types), AEC-Q101 qualified with ESD +/-30 kV, with -H appended for automotive part numbers. Source: AMSEMI datasheet 8060057 (Rev. 2026-04-23).