SMA6J43CA-Q - 600W 43V Bidirectional TVS Diode | Bourns
MPN: SMA6J43CA-Q β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.0523 | $0.05 |
| 10 | $0.048 | $0.48 |
| 100 | $0.041 | $4.10 |
| 500 | $0.035 | $17.50 |
| 1,000 | $0.029 | $29.00 |
SMA6J43CA-Q Overview
A transient voltage suppressor diode is a circuit-protection semiconductor designed to clamp fast voltage transients, such as those caused by inductive load switching, lightning-induced surges, and electrostatic discharge (ESD). TVS diodes sit within the broader voltage-suppression hierarchy that spans varistors, gas discharge tubes, and TVS thyristors. When a transient exceeds the breakdown voltage, the TVS avalanches within nanoseconds and diverts surge current to ground, clamping the protected rail to a safe level.
Key features of the SMA6J43CA-Q include 600 W peak pulse power per the 10/1000 us waveform, 5% breakdown voltage tolerance, bidirectional polarity for AC lines and symmetric signal protection, and a glass-passivated junction for long-term stability. The SMA package supports surface-mount reflow assembly and roughly 5.0 W steady-state power dissipation.
The SMA6J-Q series is specified for voltage transient and ESD protection in data lines and DC power supplies. Typical applications include automotive 24 V and 42 V rail protection, industrial DC bus clamping, telecom line cards, and surge protection at power input connectors of harsh-environment equipment.
When designing with this device, remember that the 43 V standoff means the diode begins conducting near 47.8 V minimum breakdown; downstream circuits must tolerate the 69.4 V worst-case clamp at full 8.7 A surge. Ground-path inductance must be minimized so the clamp voltage is not inflated during fast transients.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for SMA6J43CA-Q 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:
SMA6J43CA
β Drop-Inβ In Stock
$0.09 / Unit
View Datasheet βSMA6J43CA
β Drop-Inβ In Stock
$0.09 / Unit
View Datasheet βSMAJ43CA
β Drop-Inπ Reference alternative (not in catalog)
SMAJ43CA
β Drop-Inπ Reference alternative (not in catalog)
SM6T43CA
β Drop-Inπ Reference alternative (not in catalog)
SMA6J43CA-Q Maximum Ratings & Electrical Characteristics
| Product Type | Bidirectional TVS Diode |
| Series | SMA6J-Q (AEC-Q101) |
| Working Standoff Voltage (VWM) | 43 V |
| Breakdown Voltage (VBR) | 47.8 V min (5% tolerance) |
| Clamping Voltage (VC) | 69.4 V max at IPP |
| Peak Pulse Current (IPP) | 8.7 A |
| Peak Pulse Power (PPP) | 600 W (10/1000 us) |
| Polarity | Bidirectional |
| Steady State Power Dissipation | 5.0 W |
| Package | DO-214AC (SMA) |
| Mounting Type | Surface Mount |
| Voltage Tolerance | 5% |
| Automotive Qualification | AEC-Q101 qualified |
| Response Time | Fast avalanche response (ns-class) |
| UL Recognition | Plastic package has Underwriters Laboratory recognition (per datasheet features) |
SMA6J43CA-Q Pin Configuration
| Pin 1 | A1 β Terminal 1 - bidirectional TVS terminal (no polarity) |
| Pin 2 | A2 β Terminal 2 - bidirectional TVS terminal (no polarity) |
Typical Applications
SMA6J43CA-Q is suitable for 6 applications: Automotive 24V Rail Protection, Industrial DC Bus Surge Clamping, Telecom and Data Line Protection, Power Supply Input Protection, Motor Drive and Solenoid Load Protection, Harsh-Environment Equipment I/O Protection.
Automotive 24V Rail Protection
The SMA6J43CA-Q fits 24 V automotive and heavy-vehicle DC rails directly: its 43 V working standoff rides above nominal and load-dump-adjacent operating voltages without conducting, while its AEC-Q101 qualification satisfies automotive component quality requirements. Positioned at the power input connector, the diode avalanches within nanoseconds during inductive-load switching transients, clamping the rail to a maximum of 69.4 V at the full 8.7 A surge. In practice, place the TVS directly across the input with short, wide traces to the ground plane; the low package inductance of the SMA footprint keeps effective clamping close to the datasheet value even on fast edges.
Recommended
Industrial DC Bus Surge Clamping
Industrial 24 V control cabinets and PLC input stages face repetitive transients from contactors, solenoids, and motor switching. The SMA6J43CA-Q is appropriate here because its 600 W / 10/1000 us surge rating absorbs the energy-class of these events, and its 5% breakdown tolerance (47.8 V minimum) guarantees predictable turn-on margin above the 24 V bus. Mounting the bidirectional diode across the supply input requires no polarity decision, simplifying BOM reuse on both positive and symmetric lines. For designs with sustained overloads, pair the TVS with a series fuse or PTC so surge energy is shared predictably rather than stressing the diode beyond its single-pulse rating.
Recommended
Telecom and Data Line Protection
The SMA6J-Q series is specified by Bourns for ESD and transient protection on data lines. On lines carrying low-voltage DC bias with superimposed transients, such as 24 V loop-powered interfaces, the 43 V standoff prevents the TVS from loading the signal, while nanosecond avalanche response intercepts ESD and crosstalk-induced spikes before they reach line drivers. Because the device is bidirectional, one part protects both line polarities, halving component count on differential pairs. Keep the diode physically adjacent to the connector with a direct low-inductance return path; series impedance between the line and the TVS (a small resistor or ferrite) improves clamping effectiveness by forcing surge current through the diode rather than into the IC.
Recommended
Power Supply Input Protection
At the input of AC-DC or DC-DC converters, the SMA6J43CA-Q shields downstream MOSFETs and controllers from supply-line surges. Its 600 W rating handles 10/1000 us surge events, and clamping at 69.4 V maximum keeps downstream components with 75 V-plus ratings inside their safe area. In multi-stage protection, the TVS acts as the fast, precise second stage after a higher-energy varistor, catching the residual fast edge that the varistor is too slow for. Estimated design check: with a 24 V input and the TVS clamping a 3 A-limited surge, the diode conducts for microseconds and dissipates a bounded pulse energy well within its 600 W single-pulse envelope; verify against the Bourns surge curves for your source impedance.
Recommended
Motor Drive and Solenoid Load Protection
Switching inductive loads such as solenoids, relays, and small motors generates fast, high-energy flyback transients on the supply rail. The SMA6J43CA-Q placed across the load supply terminals clamps these events to 69.4 V maximum, protecting the low-side or high-side switch from avalanche stress beyond its own rating. Its bidirectional construction is valuable here because the inductive kick swings both polarities during switching transitions. Design consideration: for repetitive switching at high frequency, the diode absorbs energy every cycle, so verify average power against the 5.0 W steady-state dissipation limit and provide copper pad area for heat spreading in the SMA footprint.
Recommended
Harsh-Environment Equipment I/O Protection
Bourns positions the SMA6J-Q series for high-reliability power supplies and equipment in harsh environments, where field wiring can inject lightning-induced or switching surges into exposed terminals. The glass-passivated junction and UL-recognized plastic SMA package provide long-term parametric stability under temperature cycling and humidity. On outdoor or vehicle-mounted controllers, the SMA6J43CA-Q at each external power and signal entry point clamps surges before they reach internal electronics, with the 43 V standoff tolerating 24 V field wiring faults on general-purpose inputs. Combine with board-level series resistance or PTC elements to coordinate energy sharing across the protection chain.
Recommended
Recommended Products Summary
Engineering reference data for SMA6J43CA-Q β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SMA6J43CA (Bourns) | SMA6J43CA (Littelfuse) | SMAJ43CA (onsemi) | SM6T43CA (ST) |
|---|---|---|---|---|---|
| Package | DO-214AC (SMA) | DO-214AC (SMA) - same | DO-214AC (SMA) - same | DO-214AC (SMA) - same | DO-214AC (SMA) - same |
| Brand | Bourns | Bourns | Littelfuse | onsemi | STMicroelectronics |
| Working Standoff Voltage | 43 V | 43 V | 43 V | 43 V | 43 V |
| Peak Pulse Power | 600 W (10/1000 us) | 600 W | 600 W | 600 W | 600 W class |
| Polarity | Bidirectional | Bidirectional | Bidirectional | Bidirectional | Bidirectional |
Key Differentiators
- AEC-Q101 automotive qualification in a 600 W SMA TVS (vs SMA6J43CA (Bourns standard grade))
- Lower worst-case clamp than onsemi SMAJ43CA (vs SMAJ43CA)
- Bidirectional polarity-free assembly (vs SM6T43CA)
Design Notes
Minimize the loop inductance between the TVS diode, the protected rail, and ground. Even a few nanohenries of trace inductance adds L*di/dt overshoot on top of the 69.4 V clamp during fast transients, defeating the protection. Place the SMA6J43CA-Q within a few millimeters of the connector or load switch it protects, use short wide traces (at least 2 mm) on both terminals, and connect the ground terminal directly to a low-impedance ground plane with multiple vias.
Coordinate surge energy across the protection chain. The SMA6J43CA-Q absorbs 600 W on a 10/1000 us pulse (8.7 A); surges sourced from low-impedance supplies or long field wiring can exceed this single-pulse rating. For high-energy environments, add a series impedance (resistor, PTC, or inductor) between the source and the TVS so surge current is limited, or add a front-end varistor in a two-stage arrangement. Estimated: a 1-ohm series resistor limits an 80 V transient to roughly 36 A before clamping, well within a manageable range for the diode.
Do not undersize the standoff margin: the SMA6J43CA-Q begins to conduct near 47.8 V minimum breakdown, so any rail operating above about 43 V continuous will cause leakage and heating. Verify the worst-case steady-state rail voltage including tolerance and ripple stays below the 43 V standoff. Also remember that although this is the automotive -Q grade part, downstream circuits must themselves tolerate the 69.4 V worst-case clamp; check the absolute maximum ratings of connected ICs against the clamp voltage, not just the nominal rail.
For repetitive surge events or elevated ambient temperature, provide copper pad area for heat spreading in the SMA footprint. The DO-214AC package dissipates about 5.0 W steady-state at rated conditions, but realistic designs should derate for ambient temperature and pulse repetition rate per the Bourns SMA6J-Q series derating curves. Estimated: repetitive pulses at 1% duty cycle at 200 W average-class peaks average roughly 2 W, requiring at least 1 square centimeter of copper on both terminals to keep the junction temperature within limits.
Compliance Information
AEC-Q101 qualified per Mouser listing and Bourns SMA6J-Q series description. RoHS/REACH/halogen-free status not stated in provided data - datasheet archive notes indicate RoHS-compliant product for the SMA6J series but this should be confirmed with the manufacturer.
