SMA6J43CA - 600W Bidirectional TVS Diode 43V | Littelfuse
MPN: SMA6J43CA β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.32 | $0.32 |
| 10 | $0.26 | $2.60 |
| 100 | $0.17 | $17.00 |
| 500 | $0.12 | $60.00 |
| 1,000 | $0.09 | $90.00 |
SMA6J43CA Overview
A TVS diode is a silicon avalanche protection device clamped in parallel with the circuit it protects. Within the power-management hierarchy, it belongs to the surge protector family alongside varistors and gas discharge tubes; unlike MOVs, silicon TVS diodes respond in picoseconds with tightly controlled clamping voltages, making them the preferred choice for protecting sensitive semiconductors from electrostatic discharge (ESD), inductive load switching, and lightning-induced transients.
Key features include the 600 W peak pulse power rating (10/1000 us waveform), bidirectional polarity that blocks and clamps in both directions, 5% breakdown voltage tolerance, and a steady-state power dissipation of 5.0 W. The glass-passivated junction ensures long-term reliability, and the response time is typically less than 1.0 ns, fast enough to intercept ESD events per IEC 61000-4-2 type threats.
The SMA6J43CA uses a planar, glass-passivated avalanche junction structure. Its bidirectional construction consists of two avalanche junctions in series-opposed configuration, giving symmetric clamping at 69.4 V for both positive and negative surge events - important for AC lines, symmetric signal pairs, and circuits that see reverse transients.
Typical applications include automotive 42 V rail transient protection, industrial 24-36 V DC bus clamping, telecom line cards, and surge protection on power input stages of motor drives and power supplies. The 43 V standoff accommodates nominal 36-40 V rails with margin.
Design consideration: at 8.7 A peak, the package must dissipate the surge energy into copper - provide at least adequate PCB copper area on both SMA terminals. Remember the bidirectional CA suffix means leakage flows in both directions; use the unidirectional SMA6J43A for DC rails where a clamping diode forward drop is acceptable.
This page synthesizes verified distributor data, drop-in cross-brand alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for SMA6J43CA β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
SMA6J43A
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SMA6J40CA
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SMA6J48CA
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SMA6J43CA
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View Datasheet βSMA6J43CA Maximum Ratings & Electrical Characteristics
| Product Type | Bidirectional TVS Diode |
| Peak Pulse Power (10/1000us) | 600 W |
| Reverse Standoff Voltage (Vrwm) | 43 V |
| Breakdown Voltage (Vbr) | 47.7 V min at 1 mA |
| Breakdown Voltage Tolerance | 5 % |
| Clamping Voltage (Vc) | 69.4 V max at 8.7 A |
| Peak Pulse Current (Ipp) | 8.7 A |
| Polarity | Bidirectional |
| Steady State Power Dissipation | 5.0 W |
| Response Time | < 1.0 ns (typical) |
| Junction Type | Glass passivated |
| Package | DO-214AC (SMA) |
| Mounting Style | SMD/SMT |
| Operating Temperature Range | -55C to +150C |
| RoHS Status | Compliant |
SMA6J43CA Pin Configuration
| Pin 1 | Cathode 1 / Anode 2 β Bidirectional TVS terminal 1 - non-polarized; connect to line to protect |
| Pin 2 | Cathode 2 / Anode 1 β Bidirectional TVS terminal 2 - non-polarized; connect to line to protect |
Safe Operating Area - Peak Pulse Power Derating (600W, 10/1000us)
Typical Applications
SMA6J43CA is suitable for 6 applications: Automotive 42V Rail Transient Protection, Industrial 24-36V DC Bus Clamping, Telecom and Data Line Surge Protection, Power Supply Input Stage Protection, Motor Drive and Inverter DC Link Protection, Battery-Powered and Portable Equipment Input Protection.
Automotive 42V Rail Transient Protection
The SMA6J43CA fits 42 V automotive power rails because its 43 V reverse standoff voltage sits just above the nominal rail, keeping leakage minimal during normal operation, while its 600 W / 8.7 A surge rating absorbs load-dump and inductive-switching transients defined in automotive transient environments. Placed directly across the vehicle power input in the DO-214AC (SMA) footprint, it clamps positive surges at 69.4 V maximum and, being bidirectional, also clamps negative transients at symmetric voltage - valuable where reverse-polarity events occur. The -55C to +150C operating range covers under-hood conditions; combine with a series fuse or PTC and follow the device with a downstream lower-voltage TVS for load-switching ECUs.
Recommended
Industrial 24-36V DC Bus Clamping
Industrial 24 V and 36 V DC buses routinely experience inductive kick from contactors, solenoids, and long cable runs. The SMA6J43CA's 43 V standoff provides comfortable margin above a 36 V bus while still clamping at 69.4 V maximum - low enough to protect 60 V-rated MOSFETs and input stages downstream. Its bidirectional CA polarity handles the symmetric transients typical of motor and relay switching. Mounted in the compact 2-pin SMA package, it adds negligible BOM cost (sub-$0.10 at volume as of 2026-09-14) and occupies minimal PCB area. For longer surge events, place it in parallel with an MOV at the entry point; the TVS handles the fast residual edge with sub-nanosecond response that varistors cannot match.
Recommended
Telecom and Data Line Surge Protection
Telecom line cards and symmetric data pairs see bipolar surges from lightning induction and cable discharge, making a bidirectional TVS like the SMA6J43CA the correct topology choice. Its symmetric 69.4 V clamping protects line transformers and interface ICs rated above 70 V, while the 43 V standoff accommodates elevated DC feeding voltages on the pair. The sub-nanosecond avalanche response intercepts ESD-class fast edges that slower protection devices let through. On the PCB, route the protected trace directly through the two SMA pads with a solid ground plane to minimize loop inductance - a few nH of series inductance can add tens of volts of overshoot at 8.7 A surge levels.
Recommended
Power Supply Input Stage Protection
AC-DC and DC-DC power supplies use the SMA6J43CA at the input connector to intercept the first microsecond of a surge before bulkMOV or flyback protection responds. At 43 V standoff it protects inputs derived from nominal 36-40 V rails, clamping at 69.4 V so downstream rectifiers and controller ICs rated at 80-100 V retain margin. The 600 W rating with the 10/1000 us waveform covers the energy of standard surge test waveforms; the 5.0 W steady-state rating handles continuous leakage power. Because the device is bidirectional, a single SMA6J43CA protects both polarities, simplifying the front-end BOM compared with back-to-back unidirectional pairs.
Recommended
Motor Drive and Inverter DC Link Protection
Motor drives with long motor cable runs experience reflected-wave voltage spikes on the DC link. Placing SMA6J43CA devices across the 36-40 V DC link of low-voltage drives (24-48 V systems) clamps these spikes at 69.4 V, protecting 60-75 V rated power MOSFETs before their avalanche limits are reached. The device's fast sub-nanosecond response handles dv/dt edges from fast switching, and the SMA package's low profile suits dense power stages. For high-energy events, use it as the fast clamp in parallel with bulk capacitance and larger TVS family members. Keep the TVS leads/pads directly across the link capacitor terminals to minimize overshoot from trace inductance at surge currents up to 8.7 A.
Recommended
Battery-Powered and Portable Equipment Input Protection
Battery packs and charging inputs in portable industrial equipment benefit from the SMA6J43CA where pack voltages approach 36-42 V (e.g., 10-cell lithium stacks). Its 43 V standoff tolerates the pack maximum while clamping charger transients and hot-plug spikes at 69.4 V, protecting charge controllers and protection ICs. The small, thin DO-214AC (SMA) package fits space-constrained boards, and its glass-passivated junction ensures reliability across -55C to +150C exposure. The bidirectional configuration protects against both overvoltage events and negative spikes from reversed inductive loads such as vibration motors. Volume cost below $0.10 makes per-port protection economically viable as of 2026-09-14.
Recommended
Recommended Products Summary
Engineering reference data for SMA6J43CA β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SMA6J43A | SMA6J40CA | SMA6J43CA (Bourns) | SMA6J43CA (MDD) |
|---|---|---|---|---|---|
| Package | DO-214AC (SMA) | DO-214AC (SMA) - same | DO-214AC (SMA) - same | DO-214AC (SMA) - same | DO-214AC (SMA) - same |
| Brand | Littelfuse | Littelfuse | Littelfuse | Bourns | MDD (Microdiode Semiconductor) |
| Peak Pulse Power | 600 W | 600 W | 600 W | 600 W | 600 W |
| Standoff Voltage | 43 V | 43 V | 40 V | 43 V | 43 V |
| Clamping Voltage | 69.4 V at 8.7 A | 69.4 V at 8.7 A (positive clamp) | 64.5 V at 9.3 A | 69.4 V at 8.7 A | 69.4 V at 8.7 A |
| Polarity | Bidirectional | Unidirectional | Bidirectional | Bidirectional | Bidirectional |
| Peak Pulse Current | 8.7 A | 8.7 A | 9.3 A | 8.7 A | 8.7 A |
| Operating Temperature | -55C to +150C | -55C to +150C | -55C to +150C | -55C to +150C | -55C to +150C |
Key Differentiators
- 600 W surge rating on the compact SMA footprint (vs SMAJ43CA (400 W SMAJ series))
- Bidirectional symmetric clamping (vs SMA6J43A (unidirectional))
- Fully multi-sourced part number (vs Single-source specialty TVS parts)
Design Notes
Minimize loop inductance between the TVS and the protected line: place the SMA6J43CA within a few millimeters of the connector or input node and use a solid ground/power plane. At the 8.7 A peak pulse current, even 10 nH of trace inductance adds roughly V = L*di/dt overshoot that can exceed the clamp voltage margin. Use wide, short traces (at least 2 mm) into both SMA pads and provide adequate copper area for surge energy dissipation.
Do not operate the rail above the 43 V standoff voltage - above Vrwm the leakage rises rapidly and approaching the 47.7 V breakdown window the device begins conducting continuously, heating and potentially failing. Verify that supply tolerances (e.g., a 36 V bus with +10% tolerance plus ripple) stay safely below 43 V at maximum temperature. Also confirm the CA bidirectional suffix matches your topology: for DC rails where forward clamping at -0.7 V is acceptable, the SMA6J43A gives better negative-rail protection.
Estimated: for surge events longer than the 10/1000 us rating waveform, derate the 600 W peak pulse power per the manufacturer's derating curve (power capability decreases approximately linearly with increasing ambient temperature above 25C). For repetitive surges, verify the average power (surge energy x repetition rate) stays below the 5.0 W steady-state rating with proper copper area; otherwise consider stepping up to the SMBJ (600 W SMB) or 5KP (1500 W) families for the surge energy, keeping the SMA6J43CA as the fast first-stage clamp.
Compliance Information
RoHS compliance typical for the Littelfuse SMAJ/6J series; AEC-Q100 status not stated in provided data. REACH and halogen-free status not found in provided data.
