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STMicroelectronics LDP24A
- Part No.:
- LDP24A
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- R-6, Axial
- Datasheet:
-
LDP24A.pdf
- Description:
- TVS DIODE 24VWM 40VC R6
- Quantity:
- Payment:
- Shipping:
Inventory:121
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Product details
Overview
LDP24A from STMicroelectronics is a unidirectional transient voltage suppressor (TVS) diode designed specifically for automotive load dump protection in 24 V systems. It features a 24 V stand-off voltage (VRM), 25–32 V breakdown voltage (VBR at 1 mA), 40 V clamping voltage (VCL at 85 °C), and 30 A peak pulse current (IPP, 40 ms pulse). It is used to safeguard engine control units (ECUs), body control modules, and powertrain sensors against ISO 7637-2 Pulse 5 overvoltage events.
For engineers reviewing the LDP24A datasheet, LDP24A pinout, LDP24A application, or LDP24A equivalent, key selection criteria include clamping performance under 85 °C junction temperature, thermal resistance on infinite heatsink (15 °C/W), compliance with ISO/DTR 7637 load dump test conditions, and suitability for high-energy transients up to 500 A non-repetitive surge current.
Technical Context
The LDP24A operates as a unidirectional avalanche-clamping device triggered by overvoltage exceeding its breakdown threshold. Its clamping behavior is characterized by a low dynamic impedance during transient events, ensuring rapid voltage limiting to ≤40 V at 30 A (Tj = 85 °C), while maintaining <300 µA leakage at 24 V and 85 °C.
Thermally, it supports continuous operation up to 175 °C junction temperature and withstands 230 °C lead temperature for 10 s during soldering. Its Rth(j-a) of 15 °C/W (Llead = 10 mm) enables stable power dissipation up to 5 W on an infinite heatsink, with derating to zero at 100 °C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRM | 24 V - Maximum reverse stand-off voltage before significant conduction; defines system operating voltage margin. |
| VBR (min/typ/max) | 25 / - / 32 V @ 1 mA - Ensures reliable turn-on above nominal 24 V rail without false triggering. |
| VCL | 40 V @ Tj = 85 °C, IPP = 30 A - Limits transient voltage seen by protected ICs to safe levels during ISO 7637-2 Pulse 5. |
| IPP | 30 A @ tp = 40 ms - Sustains standardized automotive load dump energy without degradation. |
| Rth(j-a) | 15 °C/W - Enables 5 W continuous dissipation on infinite heatsink; critical for thermal design in enclosed ECUs. |
| C (at VR = 0 V) | 8000 pF @ 1 MHz - High capacitance limits use in high-speed signal lines but acceptable for power rail protection. |
| IFSM | 500 A @ tp = 10 ms - Withstands short-circuit fault currents without metallization failure. |
Pinout & Package
Package: R6 plastic case (axial leaded, DO-201AD compatible), weight 2.048 g, UL94-V0 compliant resin.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Connected to ground or low-side return path | Completes clamping path during overvoltage; must be routed with low-inductance ground connection. |
| Cathode | Connected to protected 24 V supply rail | Receives transient energy; polarity ensures unidirectional clamping only during positive overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| ISO 7637-2 Pulse 5 compliance | Validated per Schaffner NSG 506 C generator (Vs = 86.5 V, t = 200 ms, Ri = 2 Ω); protects against real-world alternator load dump. |
| High surge robustness | Withstands 500 A non-repetitive surge (10 ms) and 30 A 40 ms pulses without parameter shift or failure. |
| Temperature-stable clamping | VCL remains ≤40 V at 85 °C junction; αT = 10 × 10⁻⁴ /°C ensures predictable VBR drift across automotive temperature range. |
| Low-leakage standby | IRM ≤ 300 µA at 24 V and 85 °C - minimizes quiescent power loss in always-on vehicle modules. |
Applications
| Engine Control Unit (ECU) Power Input Protection | Body Control Module (BCM) Battery Rail Protection |
|---|---|
Use Scenario: Protects microcontroller power rails and analog sensor interfaces during alternator load dump events in gasoline/diesel engine compartments. IC Role / Device Role / Timing Role: Unidirectional TVS clamps 86.5 V transients to ≤40 V within nanoseconds, preserving downstream LDOs and CAN transceivers. Use Value: Prevents latch-up or permanent damage to 5 V/3.3 V logic supplies when exposed to ISO 7637-2 Pulse 5 waveforms. | Use Scenario: Shields BCM power inputs from battery line transients caused by sudden alternator disconnection or relay switching. IC Role / Device Role / Timing Role: Acts as primary overvoltage clamp on 24 V main input, coordinating with secondary ceramic capacitors to absorb energy. Use Value: Enables reliable operation of LIN bus peripherals and LED drivers without brownout or reset during repeated load dump cycles. |
| Transmission Control Unit (TCU) Power Stage Protection | Commercial Vehicle Telematics Power Supply Protection |
Use Scenario: Installed upstream of DC-DC converters supplying gate drivers and solenoid controllers in automatic transmissions. IC Role / Device Role / Timing Role: Limits transient voltage before buck converter input stage, preventing MOSFET avalanche failure and controller reset. Use Value: Maintains functional safety integrity (ASIL-B relevant) by ensuring uninterrupted power delivery during harsh electrical environments. | Use Scenario: Used in fleet management telematics units powered directly from truck/trailer 24 V battery systems. IC Role / Device Role / Timing Role: Primary transient suppression element on main power entry, rated for extended life under cyclic 200 ms Pulse 5 stress. Use Value: Extends field lifetime by eliminating premature failures due to cumulative load dump exposure in long-haul applications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar load dump protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ24A | Lower Ppp rating (600 W vs. 1200 W peak), higher VCL (43 V), smaller SMB package (lower thermal mass). | More suitable for space-constrained PCBs with lower energy transients; not validated for full ISO 7637-2 Pulse 5. | Select when board area is critical and peak pulse energy is ≤600 W. |
| 1.5KE27A | Higher VBR (27–30 V), higher VCL (45 V), glass-passivated DO-201 package, 1500 W peak power. | Broader industrial use; lacks explicit ISO 7637-2 certification and automotive qualification documentation. | Select for non-automotive 24 V systems requiring higher surge margin and no automotive compliance mandate. |
Compared with SMBJ24A and 1.5KE27A, the LDP24A offers certified ISO 7637-2 Pulse 5 performance, tighter VBR tolerance, and optimized thermal design for sustained automotive under-hood operation-making it the preferred choice for ECU, BCM, and TCU applications demanding OEM-level validation.
Availability
LDP24A is available at Aetrix Electronics and suitable for engine control units, body control modules, and transmission control units requiring stable component supply in automotive production programs.
Supply support for LDP24A includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing silicon solutions for automotive, industrial, and consumer markets since 1987.
The LDP series is part of ST's automotive-grade protection portfolio, engineered specifically to meet stringent ISO 7637-2 requirements for 12 V and 24 V vehicle electrical systems.
FAQ
What is the maximum clamping voltage of the LDP24A under real automotive conditions?
The LDP24A clamps to ≤40 V at 30 A peak pulse current when junction temperature is 85 °C, per ISO 7637-2 Pulse 5 test conditions (86.5 V, 200 ms, 2 Ω source impedance). This value is measured and guaranteed-not simulated-and reflects actual performance in under-hood thermal environments.
Can the LDP24A be used in 12 V automotive systems?
No-the LDP24A is specified for 24 V nominal systems. Its 24 V stand-off voltage (VRM) and 25–32 V breakdown range make it unsuitable for 12 V rails, where premature conduction and excessive leakage would occur. ST offers LDP12A and LDP15A variants for 12 V applications.
Does the LDP24A require a heatsink for continuous operation?
It does not require an external heatsink for transient suppression, but continuous power dissipation is limited to 5 W only with an infinite heatsink. In typical PCB mounting (no heatsink), derating applies: at 85 °C ambient, max continuous power drops to ~1.8 W per Fig. 4. For sustained high-power scenarios, thermal vias and copper pour are recommended.
How does the LDP24A differ from standard Zener diodes in load dump protection?
Unlike general-purpose Zeners, the LDP24A is optimized for high-energy transients: it delivers 30 A IPP (40 ms), 500 A IFSM (10 ms), and maintains stable VCL across temperature. Standard Zeners lack surge ratings, thermal robustness, and ISO 7637-2 validation-making them prone to thermal runaway or parameter shift during load dump events.
LDP24A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- R-6, Axial
- Series:
- LDP
- Packaging:
- Cut Tape (CT)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 24V
- Voltage - Breakdown (Min):
- 25V
- Voltage - Clamping (Max) @ Ipp:
- 40V
- Current - Peak Pulse (10/1000µs):
- 30A (8/20µs)
- Power - Peak Pulse:
- -
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 8000pF @ 1MHz
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- R-6
LDP24A FAQ
1.How can I place an order for LDP24A through Aetrix?
Please submit a Request for Quotation (RFQ) for LDP24A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LDP24A reliable?
The price and inventory of LDP24A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LDP24A is usually 5 days.
3.What payment methods are accepted for LDP24A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LDP24A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LDP24A?
LDP24A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LDP24A order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LDP24A?
For technical support, including LDP24A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LDP24A requirements.
6.How does Aetrix verify that LDP24A is sourced from the original manufacturer or authorized distributors?
All LDP24A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LDP24A meets industry standards.
7.What is the process for return or replacement of LDP24A?
All LDP24A units undergo pre-shipment inspection (PSI). If there is an issue with LDP24A, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LDP24A part is unused and in its original packaging.
Return procedure for LDP24A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LDP24A Tags
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Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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