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STMicroelectronics RBO40-40T
- Part No.:
- RBO40-40T
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- TO-220-3
- Datasheet:
-
RBO40-40T.pdf
- Description:
- TVS DIODE 20VWM 40VC TO220AB
- Quantity:
- Payment:
- Shipping:
Inventory:7,111
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Product details
Overview
RBO40-40T from STMicroelectronics is a monolithic automotive-grade discrete protection device integrating reversed-battery diode (D1), negative-surge Transil (T1), and load-dump Transil (T2) in a single TO-220AB package. It delivers 40 A DC forward current, ±40 V max clamping voltage, and 80 V peak load dump voltage compliance with ISO/DTR 7637 Pulse 5 - used to safeguard motor control modules and body electronics against polarity reversal and transient overvoltages.
For engineers reviewing the RBO40-40T datasheet, RBO40-40T pinout, RBO40-40T application, or RBO40-40T equivalent, key selection criteria include its triple-function integration, 1.0 °C/W junction-to-case thermal resistance, 40 V clamping at 37.5 A (T1) and 20 A (T2), and validated performance under 120 A non-repetitive surge current.
Technical Context
The RBO40-40T implements three co-integrated protection functions on one silicon die: D1 acts as a series-blocking diode for reverse-battery events; T1 clamps negative transients (e.g., relay coil flyback) between output and ground; T2 suppresses positive load-dump surges (up to 80 V) between input and output. All functions share common thermal and mechanical design within the TO-220AB package.
Its electrical behavior is defined by distinct breakdown thresholds (24–32 V typ. for both T1/T2), low-leakage operation (<10 µA at 20 V), and temperature-stable clamping (9×10⁻⁴/°C VBR coefficient). The 3000 pF D1 capacitance and 8000 pF T2 capacitance support EMI filtering while maintaining fast transient response.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| DC Forward Current (D1) | 40 A at Tc = 75°C - supports continuous motor drive rail protection without external heatsink in moderate-power applications |
| Clamping Voltage (T1) | 40 V max at IPP = 37.5 A (10/1000 µs) - limits negative transients to safe levels for downstream MOSFET gate drivers |
| Clamping Voltage (T2) | 40 V max at IPP = 20 A (10/1000 µs) - suppresses ISO 7637-2 Pulse 5 load dump surges before they reach sensitive ICs |
| Breakdown Voltage (T1/T2) | 24–32 V typ. at IR = 1 mA - establishes precise turn-on threshold for transient clamping without false triggering |
| Junction-to-Case Thermal Resistance | 1.0 °C/W - enables high-power pulse handling (1500 W peak) with direct tab mounting to chassis or heatsink |
| Storage/Operating Temperature | −40 to +150 °C - meets extended automotive ambient requirements for engine bay and powertrain locations |
| Peak Pulse Power (T1) | 1500 W at Tj initial = 25°C, 10/1000 µs - sustains repeated load dump events without thermal runaway |
Pinout & Package
Package: TO-220AB (3-lead, insulated tab), with Pin 1 = Input (battery side), Pin 2 = GND (connected to metal tab), Pin 3 = Output (load side).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Input (Anode of D1, Cathode of T2) | Connects to vehicle battery; carries full load current and absorbs positive load dump energy via T2 |
| Pin 2 | GND / Tab (Cathode of D1, Anode of T1) | Electrically tied to metal tab; serves as common reference and thermal path; must be mounted to heatsink |
| Pin 3 | Output (Cathode of D1, Anode of T2, Cathode of T1) | Feeds protected load; blocks reverse battery flow via D1; sinks negative transients through T1 to ground |
Key Features
| Feature | Design Value |
|---|---|
| Triple-function monolithic integration | Combines reverse-battery diode, negative-transient clamp (T1), and load-dump clamp (T2) in one die - eliminates board space and interconnect reliability risks of discrete solutions |
| ISO 7637-2 Pulse 5 compliance | Validated for 5-pulse load dump testing (80 V, 40 ms, 60 s interval) - ensures robustness in modern 12 V automotive systems |
| Low thermal resistance | 1.0 °C/W Rth(j-c) - allows 1500 W pulse power dissipation with <100°C junction rise during 40 ms transients |
| Temperature-stable clamping | 9×10⁻⁴/°C VBR coefficient - maintains consistent protection threshold across −40°C to +150°C operating range |
Applications
| Motor Drive Protection | Body Control Module (BCM) |
|---|---|
Use Scenario: Protecting half-bridge motor drivers in seat/mirror/window actuators from battery reversal and ignition-induced transients. IC Role / Device Role / Timing Role: Series diode (D1) blocks reverse polarity; T2 clamps positive load dump; T1 shunts negative flyback from motor windings. Use Value: Prevents latch-up and destruction of gate drivers and H-bridge FETs during jump-start or alternator regulation faults. | Use Scenario: Securing microcontroller power rails and LIN/CAN transceivers in door modules and lighting controllers. IC Role / Device Role / Timing Role: D1 isolates MCU supply from reversed battery; T1/T2 jointly suppress relay-switching spikes and alternator overshoot. Use Value: Eliminates need for separate TVS arrays and series diodes - reduces BOM count and PCB area by >40%. |
| Engine Management Sensors | Start-Stop System Control |
Use Scenario: Shielding crank/cam position sensor interfaces and fuel injector drivers from cranking transients and load dump. IC Role / Device Role / Timing Role: D1 prevents reverse conduction during battery swap; T2 clamps 80 V pulses; T1 handles negative spikes from solenoid de-energization. Use Value: Ensures uninterrupted sensor signal integrity and injector timing accuracy during cold cranking and regenerative braking events. | Use Scenario: Protecting DC-DC converter inputs and battery monitoring ICs in 12 V start-stop systems subject to frequent engine restarts. IC Role / Device Role / Timing Role: D1 blocks reverse current during stop-phase battery disconnection; T1/T2 absorb repeated 40 ms load dump pulses. Use Value: Extends system lifetime by preventing cumulative degradation of power management ICs under 10,000+ restart cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar automotive transient protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SM712-TP | Bi-directional TVS only (no integrated diode); 12 V standoff; 300 W peak power | Lacks reverse-battery blocking; requires external series diode for polarity protection | Use where board space permits discrete diode + TVS and load dump energy is below 300 W |
| SP1003-01FTG | Unidirectional TVS array (12 V); 400 W peak; no diode function; SOD-323 package | Cannot handle 40 A DC current or load dump pulses; limited to low-power signal line protection | Select only for CAN/LIN bus ESD protection - not suitable for power rail protection |
Compared with SM712-TP and SP1003-01FTG, RBO40-40T uniquely integrates 40 A diode + dual Transil clamping in one TO-220AB package, enabling single-component protection of high-current power rails - eliminating layout complexity and failure modes associated with multi-part solutions.
Availability
RBO40-40T is available at Aetrix Electronics and suitable for automotive motor control, body electronics, engine management, and start-stop system designs requiring stable component supply and long-term lifecycle assurance.
Supply support for RBO40-40T 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, specializing in automotive, industrial, and power discrete technologies with over 40 years of automotive qualification expertise.
RBO40-40T belongs to ST's Application Specific Discretes (A.S.D.)™ portfolio, engineered specifically for integrated overvoltage and reverse-battery protection in 12 V automotive power networks - targeting cost-sensitive, high-reliability module designs.
FAQ
What is the maximum load dump voltage the RBO40-40T can withstand?
The RBO40-40T is rated for 80 V peak load dump voltage per ISO/DTR 7637 Pulse 5 (5 pulses, 60 s apart). Its T2 Transil clamps at ≤40 V during this event, limiting stress on downstream components. This rating assumes proper thermal mounting and 1.0 °C/W junction-to-case resistance.
Can RBO40-40T replace a discrete diode + TVS solution?
Yes - RBO40-40T replaces a 40 A Schottky diode plus two TVS diodes (one for negative, one for positive transients) in a single TO-220AB package. It provides identical or superior protection with reduced footprint, fewer solder joints, and guaranteed matching of thermal and dynamic characteristics across all three functions.
Is the metal tab electrically isolated in RBO40-40T?
No - Pin 2 (GND) is internally connected to the metal tab in the TO-220AB package. The tab must be mounted to a grounded heatsink or chassis. Electrical isolation requires insulating hardware (e.g., mica washer + nylon screw), and thermal interface material must not compromise the GND connection.
How does temperature affect clamping voltage performance?
Clamping voltage increases with junction temperature at a coefficient of 9×10⁻⁴/°C. At 150°C, VCL rises ~11% above 25°C value - e.g., 40 V clamping becomes ~44.4 V. Designers must verify worst-case clamping margin at max operating temperature using derated pulse power curves (Fig. 3 in datasheet).
RBO40-40T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- TO-220-3
- Series:
- RBO
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 20V
- Voltage - Breakdown (Min):
- 24V
- Voltage - Clamping (Max) @ Ipp:
- 40V
- Current - Peak Pulse (10/1000µs):
- 20A, 37.5A
- Power - Peak Pulse:
- 1500W (1.5kW)
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220
RBO40-40T FAQ
1.How can I place an order for RBO40-40T through Aetrix?
Please submit a Request for Quotation (RFQ) for RBO40-40T 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 RBO40-40T reliable?
The price and inventory of RBO40-40T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RBO40-40T is usually 5 days.
3.What payment methods are accepted for RBO40-40T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RBO40-40T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RBO40-40T?
RBO40-40T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RBO40-40T 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 RBO40-40T?
For technical support, including RBO40-40T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RBO40-40T requirements.
6.How does Aetrix verify that RBO40-40T is sourced from the original manufacturer or authorized distributors?
All RBO40-40T 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 RBO40-40T meets industry standards.
7.What is the process for return or replacement of RBO40-40T?
All RBO40-40T units undergo pre-shipment inspection (PSI). If there is an issue with RBO40-40T, 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 RBO40-40T part is unused and in its original packaging.
Return procedure for RBO40-40T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
RBO40-40T Tags
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