LM1K24CA - 30kW Bi-Directional TVS Diode, 24V SMB | Leiditech
MPN: LM1K24CA ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.18 | $0.18 |
| 10 | $0.15 | $1.50 |
| 100 | $0.12 | $12.00 |
| 500 | $0.1 | $50.00 |
| 1,000 | $0.09 | $90.00 |
| 5,000 | $0.08 | $400.00 |
LM1K24CA Overview
A TVS (transient voltage suppressor) diode is a clamping semiconductor device that operates in avalanche breakdown when the applied voltage exceeds its breakdown threshold, diverting transient energy away from sensitive circuitry. Within the power-semiconductor taxonomy, TVS diodes belong to the surge protector category, themselves a sub-class of discrete protective semiconductors. Bi-directional parts like the LM1K24CA contain a symmetrical junction structure, allowing them to clamp both positive and negative transients on AC rails, differential data lines, and floating supplies without polarity orientation concerns during PCB assembly.
Key features of the LM1K24CA include 30 kW peak pulse power dissipation on the 8/20 us surge waveform (per IEC 61000-4-5), a maximum clamping voltage consistent with high-power TVS classes, low leakage in the stand-off region, fast sub-nanosecond response time inherent to avalanche breakdown, and a robust SMB (DO-214AA) molded package with compliant leads. The SMB package provides a low thermal resistance path and a well-known land pattern that supports automated pick-and-place assembly.
Typical applications include 24 V industrial bus protection (RS-485, CAN, Profibus), automotive 24 V load-dump suppression, power-over-Ethernet port protection, sensor interface protection on factory automation lines, and general-purpose surge protection on DC supplies. The bi-directional characteristic makes it well suited to differential signal paths and AC-coupled interfaces where a unidirectional TVS would be polarity-sensitive.
When designing with this part, observe the derating curve for repetitive surges and keep PCB land patterns within the SMB recommended footprint to maintain the rated peak pulse power. Use a short, wide PCB trace from the protected line to the TVS cathode/anode pins to minimize parasitic inductance, which otherwise raises the effective clamping voltage during fast edges.
This page synthesizes distributor pricing across LCSC, Octopart, Voltkit, and JLCPCB alongside drop-in alternative guidance, comparison parameters, and practical PCB-layout considerations not aggregated in the original manufacturer datasheet.
Drop-in alternatives for LM1K24CA — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LM1K24A
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LM1K24CA Maximum Ratings & Electrical Characteristics
| Manufacturer | Shanghai Leiditech Electronic Technology Co., Ltd |
| Part Number | LM1K24CA |
| Device Type | Bi-directional TVS diode |
| Package | SMB (DO-214AA) |
| Reverse Stand-Off Voltage (Vrwm) | 24 V |
| Peak Pulse Power (Ppp) | 30 kW @ 8/20 us |
| Polarity | Bi-directional |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Description | Excell clamping capability (per Leiditech datasheet) |
LM1K24CA Pin Configuration
| Pin 1 | Terminal 1 — Bi-directional TVS terminal (anode/cathode, polarity-independent) |
| Pin 2 | Terminal 2 — Bi-directional TVS terminal (anode/cathode, polarity-independent) |
Peak Pulse Power vs Pulse Duration (8/20 us surge)
Typical Applications
LM1K24CA is suitable for 6 applications: 24V Industrial Bus Surge Protection, Automotive 24V Load-Dump Suppression, Power-over-Ethernet Port Protection, Factory Automation Sensor Interface Protection, DC Power Supply Output Protection, Telecom and Network Equipment Surge Protection.
24V Industrial Bus Surge Protection
The LM1K24CA protects 24V industrial bus rails such as RS-485, CAN, and Profibus from induced lightning and switching transients. Its 24V reverse stand-off voltage matches the nominal bus level so the device stays dark during normal operation, while the 30 kW peak pulse power on the 8/20 us waveform clamps induced surges from motor drives, solenoids, and field wiring to a safe level above the bus transceiver's absolute maximum. The bi-directional structure is essential for differential CAN/RS-485 lines where each conductor sees opposite-polarity transients during a common-mode event. Place the TVS as close as possible to the bus connector with a short, wide ground return to the chassis or earth reference, and verify the transceiver's rated transient voltage exceeds the TVS clamping voltage under worst-case peak pulse current.
Recommended
Automotive 24V Load-Dump Suppression
The LM1K24CA clamps automotive load-dump transients on 24V truck and heavy-vehicle electrical systems, where the alternator can deliver high-energy positive transients up to hundreds of volts when the battery is disconnected while the engine is running. Its 30 kW peak pulse power rating and 24V Vrwm make it suitable for placement across the battery rail near the ECU power input, where it diverts the surge energy before downstream DC-DC converters and MCUs see destructive voltages. The SMB package provides mechanical robustness under vehicle vibration, and the bi-directional configuration protects against reverse-battery and jump-start events common in service environments. Verify ISO 7637-2 pulse ratings against the LM1K24CA surge capability before approving the design.
Recommended
Power-over-Ethernet Port Protection
The LM1K24CA protects PoE PSE and PD ports on switches, midspans, and powered devices from induced surges on the cable side. Its 30 kW peak pulse power and bi-directional design let it clamp common-mode transients that couple into both mode A and mode B power pairs without polarity concerns, and the 24V stand-off comfortably exceeds the 48V PoE nominal plus tolerance while staying below the rectifier/PD controller breakdown. Mount the TVS near the RJ45 connector with a short ground return to the chassis, in parallel with a smaller ESD array for sub-1 kV events. The SMB land pattern allows easy integration alongside the Ethernet magnetics and PoE PD controller.
Recommended
Factory Automation Sensor Interface Protection
The LM1K24CA shields factory-floor sensor interfaces - proximity, photoelectric, encoders, and 4-20 mA loops - from the switching transients produced by nearby relays, motor contactors, and variable-frequency drives. Its 24V Vrwm matches 24V sensor supply rails, and the 30 kW rating absorbs the energy from cable-coupled transients on long sensor runs. The bi-directional configuration tolerates reversed wiring during field installation and protects against AC-coupled events on differential sensor outputs. Pair the TVS with a series PTC or current-limiting resistor for sustained over-voltage events, and place the device at the sensor connector entry point on the I/O board.
Recommended
DC Power Supply Output Protection
The LM1K24CA clamps transients on the output of 24V DC supplies in industrial enclosures, programmable logic controllers, and machine vision systems. Its 30 kW peak pulse power on the 8/20 us waveform handles the residual surge energy that bypasses upstream filtering, and the SMB package footprint drops directly into standard 24V protection layouts alongside input TVS devices. The bi-directional characteristic is advantageous on floating or battery-backed rails where polarity may be ambiguous during service or fault conditions. Place the LM1K24CA at the supply output terminals with low-inductance PCB traces to maximize clamping effectiveness during fast-edge transients.
Recommended
Telecom and Network Equipment Surge Protection
The LM1K24CA protects telecom line cards, network switches, and base-station equipment from induced surges on 24V battery-backed distribution rails and signaling interfaces. Its 30 kW rating meets the surge demands of GR-1089-CORE intra-building and inter-building exposure categories when paired with a primary protector, and the bi-directional design simplifies PCB layout on polarity-ambiguous feed circuits. The SMB package's low thermal resistance supports the repetitive surge duty seen in exposed plant environments. Combine the TVS with a fuse or PTC for sustained over-voltage events and verify coordination with upstream gas discharge tubes or solid-state primary protectors.
Recommended
Recommended Products Summary
Engineering reference data for LM1K24CA — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM1K24A | SMBJ24CA | SMBJ24CA | SMBJ24CA | 1SMB24CA |
|---|---|---|---|---|---|---|
| Brand | Leiditech | Leiditech | Littelfuse | Vishay Intertechnology | onsemi | Diodes Incorporated |
| Package | SMB (DO-214AA) | SMB (DO-214AA) - same | SMB (DO-214AA) - same | SMB (DO-214AA) - same | SMB (DO-214AA) - same | SMB (DO-214AA) - same |
| Reverse Stand-Off Voltage (Vrwm) | 24 V | 24 V | 24 V | 24 V | 24 V | 24 V |
| Polarity | Bi-directional | Uni-directional | Bi-directional | Bi-directional | Bi-directional | Bi-directional |
| Peak Pulse Power (8/20 us) | 30 kW | 30 kW (estimated same family) | 600 W (-98%) | 600 W (-98%) | 600 W (-98%) | lower than 30 kW |
| Mounting Type | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount |
| RoHS Compliance | Compliant | Compliant (per family) | Compliant | Compliant | Compliant | Compliant |
| Approx. Unit Price (USD) | $0.10 - $0.18 | Similar to LM1K24CA | $0.05 - $0.15 | $0.05 - $0.15 | $0.05 - $0.15 | $0.08 - $0.18 |
Key Differentiators
- 30 kW peak pulse power on 8/20 us waveform (vs Littelfuse SMBJ24CA)
- Bi-directional polarity by default (vs Leiditech LM1K24A)
- Multi-channel distributor availability at sub-$0.20 unit pricing (vs Vishay SMBJ24CA)
Design Notes
Place the LM1K24CA within 5 mm of the protected connector or supply terminal to minimize loop inductance. Use a short, wide PCB trace (at least 0.5 mm wide per ampere of peak surge current) from the protected line to one TVS terminal and from the other terminal to a low-impedance ground plane. Parasitic inductance of just a few nanohenries can raise the effective clamping voltage by tens of volts during the sub-microsecond edge of an 8/20 us surge, undermining the TVS's protection.
Estimate: peak pulse power of 30 kW for 20 us delivers approximately 0.6 J per event into the SMB package. SMB junction-to-ambient thermal resistance is in the order of 50-80 C/W depending on copper area; for non-repetitive single-pulse events this is acceptable, but repetitive surges at high power require derating per the datasheet's pulse-train curve. Add a copper pour of at least 1 square inch under the SMB land pattern to reduce steady-state thermal resistance for repetitive surge environments.
Do not assume the 24 V reverse stand-off voltage equals the breakdown voltage - the breakdown is typically 10-20% higher. Verify the protected circuit's maximum rated transient voltage exceeds the TVS's clamping voltage at the expected peak pulse current; otherwise the downstream device can fail before the TVS reaches its rated clamping point. For AC-coupled or polarity-ambiguous applications, ensure the bi-directional 'CA' suffix variant is used rather than the uni-directional 'A' variant, since polarity reversal at installation will reverse-bias a uni-directional TVS and disable protection.
Follow the SMB recommended land pattern from the IPC-7351 nominal or the manufacturer-specific pattern; do not shrink the pads or use a DO-214AB (SMC) footprint, which has different pad dimensions. Keep the TVS away from tall components that could shadow the solder joint during reflow, and ensure both terminals receive balanced thermal mass to avoid tombstoning. Add a ground pour stitch via array adjacent to the grounded terminal to provide a low-inductance return path for the surge current.
Compliance Information
RoHS compliance confirmed per Leiditech product page and GlobalSpec listing. REACH, halogen-free, and conflict-mineral status not enumerated in available data; AEC-Q100 not applicable for a discrete TVS diode unless an automotive-qualified equivalent is explicitly identified.
