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STMicroelectronics RBO08-40T
- Part No.:
- RBO08-40T
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- TO-220-3
- Datasheet:
-
RBO08-40T.pdf
- Description:
- TVS DIODE 20VWM 40VC TO220AB
- Quantity:
- Payment:
- Shipping:
Inventory:2,074
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Product details
Overview
RBO08-40T from STMicroelectronics is a monolithic automotive-grade discrete protection device integrating reversed-battery diode (D1), negative overvoltage clamp (T1), and positive overvoltage Transil (T2) in a single TO-220AB package. It delivers 8 A forward current, ±40 V clamping voltage, and complies with ISO/DTR 7637 Pulses 1/2/3a/3b for robust surge immunity in alternator-protected environments.
For engineers reviewing the RBO08-40T datasheet, RBO08-40T pinout, RBO08-40T application, or RBO08-40T equivalent, key selection criteria include its triple-function integration, 2.4 °C/W junction-to-case thermal resistance, 1500 W peak pulse power (Pin 3–2), 24 V minimum breakdown voltage, and validated performance at Tj = 150°C in motor driver and ECU power rail protection.
Technical Context
This device implements three co-integrated protection functions on one silicon die: D1 acts as a series reverse-polarity blocking diode with VF = 1.7 V @ 8 A; T1 provides negative transient clamping with VBR = 24–32 V and VCL ≤ 40 V @ 15 A; T2 handles positive transients with identical VBR/VCL specs but higher PPP = 1500 W (10/1000 µs).
The TO-220AB package features electrically isolated tab (Pin 2 = GND), enabling direct heatsinking while maintaining functional separation between input (Pin 1), output (Pin 3), and ground reference. Thermal impedance drops to 0.2×Rth(j-c) at tp = 1 ms, supporting high-energy pulse absorption without thermal runaway.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Forward Current (IF) | 8 A continuous @ Tc = 75°C - supports high-current automotive power rails without external derating |
| Clamping Voltage (VCL) | ±40 V max @ IPP = 15 A (T1) / 37.5 A (T2), 10/1000 µs - limits downstream IC stress during load-dump or inductive kick |
| Breakdown Voltage (VBR) | 24 V min @ IR = 1 mA - ensures reliable turn-on before battery reversal or surge exceeds system tolerance |
| Peak Pulse Power (PPP) | 1500 W (Pin 3–2), 10/1000 µs - sustains ISO 7637 Pulse 1 (−100 V, 400 ms) and Pulse 2b (−100 V, 100 ms) events |
| Junction-to-Case Rth | 2.4 °C/W - enables direct mounting to chassis or heatsink for stable operation up to 150°C junction temperature |
| Surge Current (IFSM) | 80 A non-repetitive @ tp = 10 ms - withstands short-duration cranking surges without failure |
| Leakage Current (IRM) | 10 µA @ VRM = 20 V, Tamb = 25°C - minimizes standby power loss in always-on vehicle modules |
Pinout & Package
TO-220AB package with electrically isolated metal tab (Pin 2 = GND). Tab serves as thermal path and circuit ground reference; Pin 1 is input/anode of D1; Pin 3 is output/cathode of D1 and connection node for T1/T2 clamping paths.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Anode of D1; Input terminal | Connects to battery positive; blocks reverse polarity when battery is misconnected |
| Pin 2 | GND reference; isolated tab | Electrically isolated metal tab used for mechanical mounting and thermal dissipation; must be tied to system ground |
| Pin 3 | Cathode of D1; Output terminal; Common node for T1/T2 | Delivers protected power to load; serves as clamping node for both positive (T2) and negative (T1) transients |
Key Features
| Feature | Design Value |
|---|---|
| Triple-function monolithic integration | Single-die implementation of reverse-battery diode + dual Transil clamps eliminates interconnect parasitics and board space vs. discrete solutions |
| ISO/DTR 7637 compliance | Validated for Pulses 1, 2, 3a, and 3b - meets OEM requirements for ECU, body control, and motor driver modules |
| High-energy pulse handling | 1500 W peak pulse power (T2) enables protection against 12 V system load-dump events without external snubbers |
| Thermal robustness | Rated for TJ = 150°C continuous operation with 2.4 °C/W Rth(j-c) - supports under-hood deployment without forced cooling |
Applications
| Engine Control Unit (ECU) Power Input | Motor Driver Protection |
|---|---|
Use Scenario: 12 V supply line feeding microcontroller, CAN transceivers, and analog sensors in engine bay. IC Role / Device Role / Timing Role: Primary front-end protection device absorbing load-dump, jump-start, and battery reversal events. Use Value: Prevents latch-up or destruction of 5 V/3.3 V regulators and MCU I/O by limiting input rail to ≤40 V during transients. |
Use Scenario: H-bridge gate driver supply rail exposed to inductive flyback from brushed DC motors. IC Role / Device Role / Timing Role: Bidirectional clamping element suppressing negative voltage spikes (T1) and positive switching overshoot (T2). Use Value: Eliminates need for separate TVS diodes across motor terminals and gate drive supplies, reducing BOM count by 2 components. |
| Body Control Module (BCM) Input | Alternator-Protected Systems |
Use Scenario: Centralized lighting, window lift, and door lock module powered directly from vehicle battery. IC Role / Device Role / Timing Role: Reverse-polarity blocker (D1) and surge suppressor (T1/T2) for always-on 12 V input stage. Use Value: Ensures zero current flow during accidental battery reversal while clamping ISO Pulse 2b (−100 V, 100 ms) to safe levels. |
Use Scenario: Modules connected to alternator output where regulated 14 V supply may experience sudden overvoltage during regulator failure. IC Role / Device Role / Timing Role: Standoff protector holding system voltage below 40 V during alternator field-circuit faults. Use Value: Maintains functionality of LIN transceivers and EEPROMs during sustained overvoltage conditions up to 150°C junction temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar reversed-battery and overvoltage protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SM712-TP | Bi-directional TVS only (no integrated diode); 12 V standoff, 33 V clamping; SOT-23 package | Lacks reverse-battery blocking function; requires external series diode for polarity protection | Use only when board space is critical and reverse-battery risk is mitigated elsewhere in design |
| SP1003-01FTG | Unidirectional TVS array (12 V standoff); 200 W PPP per channel; SO-8 package | No monolithic integration; cannot replace D1 function; limited to low-energy transients | Suitable for secondary protection downstream of RBO08-40T, not as primary front-end solution |
Compared with SM712-TP and SP1003-01FTG, RBO08-40T uniquely combines reverse-battery blocking, bidirectional clamping, and high-power pulse handling in one TO-220AB device-enabling simplified front-end architecture, reduced component count, and guaranteed compliance with automotive surge standards without external coordination.
Availability
RBO08-40T is available at Aetrix Electronics and suitable for engine control units, motor drivers, body control modules, and alternator-protected systems requiring stable component supply across automotive production lifecycles.
Supply support for RBO08-40T 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 management solutions with vertical manufacturing capabilities and AEC-Q101 qualified product lines.
RBO08-40T belongs to ST's Application Specific Discretes (A.S.D.)™ portfolio, engineered specifically for automotive power rail protection with integrated multi-threat mitigation in harsh under-hood environments.
FAQ
Can RBO08-40T be used in 24 V commercial vehicle systems?
No - RBO08-40T is specified for 12 V automotive systems only. Its 24 V minimum breakdown voltage and ±40 V clamping are optimized for nominal 12 V/14 V battery and alternator operation. For 24 V systems, ST recommends RBO16-60T (60 V clamping, 48 V VBR) or discrete dual-Transil + diode configurations rated for higher standoff.
Is the TO-220AB tab electrically connected to any internal function?
No - the metal tab in the TO-220AB package is electrically isolated and assigned exclusively to Pin 2 (GND). It serves only as a thermal conduction path and grounding point; no internal silicon structure connects to the tab outside the designated GND terminal.
What is the maximum allowable PCB copper area for thermal relief?
For optimal thermal performance, ST specifies ≥250 mm² of 2 oz copper connected to Pin 2 (tab) with ≥4 thermal vias (0.3 mm diameter) to inner ground planes. This achieves the rated 2.4 °C/W Rth(j-c); reducing copper area increases junction temperature proportionally per Fig. 4 in the datasheet.
Does RBO08-40T require external current-limiting resistors?
No - RBO08-40T operates as a passive, self-regulating protection device. Its D1 diode forward drop (1.7 V @ 8 A) and Transil dynamic resistance inherently limit fault current during clamping; no series resistor is needed or recommended for standard ISO 7637-compliant applications.
RBO08-40T 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):
- 22V
- Voltage - Clamping (Max) @ Ipp:
- 40V
- Current - Peak Pulse (10/1000µs):
- 15A, 37.5A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220
RBO08-40T FAQ
1.How can I place an order for RBO08-40T through Aetrix?
Please submit a Request for Quotation (RFQ) for RBO08-40T 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 RBO08-40T reliable?
The price and inventory of RBO08-40T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RBO08-40T is usually 5 days.
3.What payment methods are accepted for RBO08-40T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RBO08-40T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RBO08-40T?
RBO08-40T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RBO08-40T 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 RBO08-40T?
For technical support, including RBO08-40T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RBO08-40T requirements.
6.How does Aetrix verify that RBO08-40T is sourced from the original manufacturer or authorized distributors?
All RBO08-40T 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 RBO08-40T meets industry standards.
7.What is the process for return or replacement of RBO08-40T?
All RBO08-40T units undergo pre-shipment inspection (PSI). If there is an issue with RBO08-40T, 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 RBO08-40T part is unused and in its original packaging.
Return procedure for RBO08-40T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
RBO08-40T Tags
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