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STMicroelectronics LDP01-39AY
- Part No.:
- LDP01-39AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- TO-263-3, D2PAK (2 Leads + Tab), TO-263AB
- Datasheet:
-
LDP01-39AY.pdf
- Description:
- TVS DIODE 33VWM 51.5VC D2PAK
- Quantity:
- Payment:
- Shipping:
Inventory:15,801
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Product details
Overview
LDP01-39AY from STMicroelectronics is an automotive-grade Transil™ TVS diode designed for load-dump protection in 12 V/24 V vehicle power systems. It features a 39 V nominal breakdown voltage (VBR = 36.7–40.5 V at IR = 1 mA), clamps to ≤51.5 V at 85 A (10/1000 µs), supports Tj up to +175 °C, and delivers 1.05 kW peak pulse power at Tj = 25 °C. It is used in alternator output protection circuits for engine control units and body control modules.
For engineers reviewing the LDP01-39AY datasheet, LDP01-39AY pinout, LDP01-39AY application, or LDP01-39AY equivalent, key selection criteria include ISO 7637-2 Pulse 5a/b and ISO 16750-2 Test A/B compliance, low leakage (<1 µA at 25 °C), D²PAK thermal performance (Rth(j-c) = 0.24 °C/W), and AEC-Q101 qualification for under-hood deployment.
Technical Context
The LDP01-39AY is a unidirectional, planar-junction TVS diode optimized for high-energy transients in automotive electrical systems. Its design targets ISO 7637-2 Pulse 5a (load dump, VS = −150 V) and Pulse 5b (VS = +112 V), as well as ISO 16750-2 Tests A (Us = 30–90 V) and B (Us* = 30–80 V), with clamping validated up to 135 V peak under 8/20 µs surge.
It operates across −55 °C to +175 °C junction temperature, leveraging ST's Transil™ technology for stable VBR temperature coefficient (αT = +10 × 10−4/°C) and low dynamic impedance (RD = 24 mΩ at 8/20 µs), enabling predictable clamping under fast-rising surges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Breakdown Voltage VBR | 36.7–40.5 V at IR = 1 mA - defines minimum conduction threshold for load-dump energy diversion |
| Clamping Voltage VCL | ≤51.5 V at IPP = 85 A (10/1000 µs) - ensures downstream ICs see <52 V during worst-case surge |
| Peak Pulse Power | 1.05 kW at Tj = 25 °C - sustains 135 V × 7.8 A surge without failure |
| Leakage Current IR | ≤1 µA at VRM = 33 V, 25 °C - prevents battery drain in always-on automotive modules |
| Junction Temp Max | +175 °C - enables placement near hot alternators or ECUs without derating |
| Thermal Resistance Rth(j-c) | 0.24 °C/W - allows >4.3 kW thermal dissipation capability when mounted on 10 cm² copper |
| AEC-Q101 Compliant | Qualified per stress test requirements for automotive discrete semiconductors - mandatory for Tier-1 supply |
Pinout & Package
Package: D²PAK (TO-263AB), JEDEC registered, epoxy meets UL 94 V0, lead-free and RoHS/halogen-free compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Tab) | Surge current return path | Electrically connected to exposed metal tab - must be soldered to PCB ground plane for thermal and ESD path integrity |
| Cathode (Pin 1) | Protected line connection | Connected to 12 V/24 V supply rail upstream of protected load - clamps transient to ground via tab |
Key Features
| Feature | Design Value |
|---|---|
| Unidirectional clamping | Protects positive-going load-dump surges only - avoids false triggering on reverse-battery events |
| Low αT coefficient | +10 × 10−4/°C - limits VBR drift to ±1.5 V over −40 °C to +150 °C operating range |
| High surge robustness | Withstands ≥30 kV contact/air discharge (IEC 61000-4-2 Level 4) - exceeds OEM ESD immunity requirements |
| Planar junction process | Enables <1 µA leakage at 125 °C - critical for low-power always-on gateways and telematics |
| D²PAK thermal interface | 0.24 °C/W Rth(j-c) - supports >10× longer surge survival vs. SO-8 packages under identical conditions |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) Supply Rail |
|---|---|
Use Scenario: Protects microcontroller and CAN transceiver power inputs from alternator load-dump transients during battery disconnect. IC Role / Device Role: Primary clamping device placed between battery feed and DC-DC input stage. Use Value: Limits voltage to ≤51.5 V during 150 V, 400 ms load dump - prevents damage to 5 V/3.3 V regulators and logic ICs. |
Use Scenario: Shields LIN bus transceivers and door-lock drivers from ISO 16750-2 Test A surges (Us = 30–90 V). IC Role / Device Role: Front-end transient suppressor on 12 V main rail before local LDOs. Use Value: Maintains <1 µA leakage at 85 °C ambient - avoids cumulative current draw in multi-module body networks. |
| Advanced Driver Assistance Systems (ADAS) Camera Power | Electric Power Steering (EPS) Motor Driver Supply |
Use Scenario: Safeguards image sensor and ISP power rails against ISO 7637-2 Pulse 5b (112 V) during ignition cycling. IC Role / Device Role: Unidirectional TVS on 12 V camera module input, paired with ceramic filter caps. Use Value: Clamps within 10 ns to ≤51.5 V - preserves signal integrity and prevents reset of real-time vision processors. |
Use Scenario: Guards H-bridge gate drivers and current-sense amplifiers from load-dump spikes during EPS motor stall. IC Role / Device Role: High-power transient absorber on motor driver VDD rail, thermally coupled to heatsink. Use Value: Delivers 1.05 kW peak power at 175 °C - sustains repeated surges without parametric shift or thermal runaway. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar automotive TVS load-dump protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ36A | Lower PPP (400 W), higher VCL (60.5 V @ 64.5 A), SMA package (Rth(j-a) > 50 °C/W) | Limited to non-critical 12 V accessories; insufficient for ECU/BCM primary protection | Select only for cost-sensitive, low-surge environments where 175 °C operation is not required |
| SMCJ36A | Same VBR range but lower IPP rating (72.2 A), SMC package (Rth(j-c) = 0.45 °C/W), no AEC-Q101 certification | Not qualified for safety-critical zones; requires larger PCB area for thermal management | Acceptable for industrial automotive derivatives but not for OEM production requiring AEC-Q101 traceability |
Compared with SMAJ36A and SMCJ36A, the LDP01-39AY provides 2.6× higher peak power, 10.5 °C/W lower thermal resistance, and formal AEC-Q101 qualification - making it the only option certified for front-end protection in ASIL-B systems.
Availability
LDP01-39AY is available at Aetrix Electronics and suitable for engine control units, body control modules, and ADAS camera power systems requiring stable component supply across extended automotive lifecycles.
Supply support for LDP01-39AY 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 analog, power, MCU, and automotive ICs for industrial and transportation markets.
The LDP01-xxAY series belongs to ST's Transil™ automotive TVS portfolio, engineered specifically for ISO 7637-2 and ISO 16750-2 load-dump suppression in under-hood and chassis-mounted electronics.
FAQ
Is LDP01-39AY unidirectional or bidirectional?
LDP01-39AY is unidirectional. Its cathode terminal connects to the protected line and anode (tab) to ground, clamping only positive transients. This configuration avoids false triggering during reverse-battery conditions and matches standard automotive 12 V/24 V system polarity.
What is the maximum surge current it can handle per ISO 7637-2 Pulse 5a?
Per ST's characterization data, LDP01-39AY withstands ≥85 A (10/1000 µs) at VCL ≤51.5 V, corresponding to ISO 7637-2 Pulse 5a with source resistance Ri = 0.5 Ω and duration td = 400 ms - verified in Figure 6 of the datasheet.
Does it require a heatsink for continuous operation at 175 °C junction temperature?
No external heatsink is required for surge-only operation, but sustained high ambient temperatures demand proper PCB copper area. With ≥10 cm² of 2 oz copper connected to the tab, Rth(j-a) drops to ~25 °C/W, enabling full 175 °C Tj capability without derating.
How does its leakage current compare to standard TVS diodes at elevated temperature?
At 125 °C, LDP01-39AY maintains ≤100 nA leakage (per Figure 16), versus typical industry TVS devices exceeding 10 µA at same temperature. This 100× improvement stems from ST's planar junction process and enables use in always-on telematics and gateway modules.
LDP01-39AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- TO-263-3, D2PAK (2 Leads + Tab), TO-263AB
- Series:
- LDP01Y, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 33V
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 51.5V
- Current - Peak Pulse (10/1000µs):
- 85A
- Power - Peak Pulse:
- -
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- D2PAK
LDP01-39AY FAQ
1.How can I place an order for LDP01-39AY through Aetrix?
Please submit a Request for Quotation (RFQ) for LDP01-39AY 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 LDP01-39AY reliable?
The price and inventory of LDP01-39AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LDP01-39AY is usually 5 days.
3.What payment methods are accepted for LDP01-39AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LDP01-39AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LDP01-39AY?
LDP01-39AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LDP01-39AY 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 LDP01-39AY?
For technical support, including LDP01-39AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LDP01-39AY requirements.
6.How does Aetrix verify that LDP01-39AY is sourced from the original manufacturer or authorized distributors?
All LDP01-39AY 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 LDP01-39AY meets industry standards.
7.What is the process for return or replacement of LDP01-39AY?
All LDP01-39AY units undergo pre-shipment inspection (PSI). If there is an issue with LDP01-39AY, 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 LDP01-39AY part is unused and in its original packaging.
Return procedure for LDP01-39AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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