My Inquiry
My Account
onsemi 1SMB40CAT3G
- Part No.:
- 1SMB40CAT3G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB40CAT3G.pdf
- Description:
- TVS DIODE 40VWM 64.5VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:248,802
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
1SMB40CAT3G from ON Semiconductor is a bidirectional 600 W peak power Zener transient voltage suppressor (TVS) in SMB package, rated for 40 V working peak reverse voltage (VRWM), 49.1 V breakdown voltage (VBR) at 1 mA test current, and clamps to 64.5 V at 9.3 A peak pulse current. It delivers sub-1 ns response time, <5 µA leakage above 10 V, and UL 497B recognition for isolated loop circuit protection - deployed in industrial power supplies and automotive ECUs.
For engineers reviewing the 1SMB40CAT3G datasheet, pinout, applications, or equivalent options, this page provides verified electrical specs, clamping behavior under surge, thermal derating curves, SMB package mechanical dimensions, and direct alternatives with documented VRWM/VBR/IPP alignment.
Technical Context
The 1SMB40CAT3G operates as a bidirectional Zener-based TVS diode, leveraging avalanche breakdown to clamp transients across both polarities. Its design centers on low zener impedance and fast junction response (<1 ns), enabling effective suppression of ESD (Class 3 >16 kV HBM) and lightning-induced surges per IEC 61000-4-2/4-5.
It is thermally rated for 600 W peak power (10/1000 µs waveform) at TL = 25°C, with junction-to-lead thermal resistance of 25°C/W and derating to 0.55 W at TA = 25°C. The device uses ON Semiconductor's SURMETIC™ void-free molded plastic case (Case 403C) with modified L-bend leads for robust solder joint reliability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 40 V - Maximum continuous reverse operating voltage before clamping initiates; must exceed system DC bus or signal swing. |
| VBR @ IT=1 mA | 44.4–49.1 V - Verified breakdown range ensures reliable turn-on margin above VRWM without premature conduction. |
| VC @ IPP=9.3 A | 64.5 V - Clamped voltage during 10/1000 µs surge; defines maximum stress imposed on protected downstream circuitry. |
| IPP | 9.3 A - Peak pulse current capability at 64.5 V clamp; determines survivability against defined surge waveforms. |
| Ctyp @ 0 V, 1 MHz | 220 pF - Junction capacitance impacts high-frequency signal integrity; suitable for DC/low-speed data lines, not RF interfaces. |
| Leakage @ VRWM | <5 µA - Minimal standby current draw preserves efficiency in always-on systems like automotive body controllers. |
| Response Time | <1 ns - Enables suppression before transient energy couples into sensitive analog or logic circuits. |
Pinout & Package
1SMB40CAT3G is a two-terminal bidirectional TVS diode in ON Semiconductor's SURMETIC™ SMB package (Case 403C), featuring void-free thermosetting plastic encapsulation, corrosion-resistant surfaces, and modified L-bend leads for enhanced pad contact area. Polarity band is omitted due to symmetrical bidirectional operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (Bidirectional) | Transient conduction path | Both terminals conduct identically during positive or negative overvoltage events; no polarity marking required. |
| Cathode/Anode (Bidirectional) | Transient conduction path | Functionally identical to first terminal; device behaves as symmetric Zener pair across terminals. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Protects AC-coupled or floating circuits (e.g., RS-485, CAN bus stubs) without polarity constraints. |
| 600 W peak power rating | Withstands IEC 61000-4-5 Level 3 (1 kV/2 Ω) surges in industrial power input stages without failure. |
| UL 497B recognition | Validated for isolated loop circuit protection in medical and telecom equipment requiring safety certification. |
| ESD Class 3 (>16 kV HBM) | Meets stringent electrostatic discharge immunity for assembly-line handling and end-user environments. |
| Pb-free SURMETIC™ package | Complies with RoHS and J-STD-020 reflow profiles up to 260°C for 10 seconds; no lead finish concerns. |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module (BCM) ESD Suppression |
|---|---|
|
Use Scenario: Installed across DC input rails (e.g., 24 V bus) of programmable logic controllers to absorb load dump and inductive switching spikes. IC Role / Device Role / Timing Role: Voltage-clamping transient suppressor placed in parallel with bulk input capacitor and upstream fuse. Use Value: Limits rail voltage to ≤64.5 V during 9.3 A surges, preventing damage to DC-DC controllers and microcontrollers rated for 36 V max. |
Use Scenario: Mounted at connector interface of BCM PCB to suppress ESD events from human contact on door handles or switches. IC Role / Device Role / Timing Role: Fast-response bidirectional shunt element diverting ESD current away from LIN transceivers and MCU GPIOs. Use Value: Sub-1 ns response and >16 kV HBM rating ensure no latch-up or gate oxide damage to 5 V tolerant peripherals. |
| Medical Isolated Sensor Interface | Telecom Line Card Surge Protection |
|
Use Scenario: Applied across secondary-side signal lines (e.g., isolated analog sensor outputs) in patient monitoring devices certified to IEC 60601-1. IC Role / Device Role / Timing Role: UL 497B-recognized protector on isolated side of reinforced insulation barrier. Use Value: Maintains creepage/clearance compliance while clamping transients to safe levels below isolation barrier breakdown thresholds. |
Use Scenario: Used on RJ-45 Ethernet PHY interface of DSLAM line cards exposed to lightning-induced surges on copper pairs. IC Role / Device Role / Timing Role: Primary-level bidirectional TVS in series with common-mode chokes and secondary-stage protection. Use Value: 600 W peak power rating enables survival of multiple 10/1000 µs surges per IEC 61000-4-5 without degradation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SZ1SMB40CAT3G | AEC-Q101 qualified; identical VRWM/VBR/IPP specs but with automotive-specific traceability and PPAP support. | Required for automotive OEM designs needing qualification documentation and change control. | Select SZ1SMB40CAT3G when automotive qualification (AEC-Q101) and PPAP deliverables are mandatory. |
| SMAJ40A | Unidirectional; 40 V VRWM, 44.4 V VBR min, 64.5 V VC @ 9.3 A - same clamping but asymmetric conduction. | Suitable only for DC-biased lines where reverse polarity transients are absent or blocked by other means. | Choose SMAJ40A only if circuit topology guarantees unidirectional surge exposure and polarity is fixed. |
Compared with 1SMB40CAT3G, SZ1SMB40CAT3G adds automotive qualification without altering electrical performance, while SMAJ40A trades bidirectionality for unidirectional clamping - requiring careful review of signal polarity and surge direction in system-level protection schemes.
Availability
1SMB40CAT3G is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, medical isolated sensor interfaces, and telecom line card surge protection requiring stable component supply and full traceability.
Supply support for 1SMB40CAT3G 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
ON Semiconductor (now onsemi) is a global semiconductor manufacturer specializing in power management, analog, sensors, and discrete devices for automotive, industrial, and cloud power applications.
The 1SMB40CAT3G belongs to the SMB-series transient voltage suppressor family, engineered for high-energy surge immunity in harsh environments - targeting communication infrastructure, automotive electronics, and industrial controls where reliability under electrical stress is critical.
FAQ
What is the clamping voltage of the 1SMB40CAT3G under a standard 10/1000 µs surge?
The 1SMB40CAT3G clamps to a maximum of 64.5 V at 9.3 A peak pulse current (IPP), per its datasheet specification under the standardized 10/1000 µs double-exponential surge waveform. This value defines the upper voltage limit imposed on protected circuitry during transient events and must be compared against the absolute maximum ratings of downstream components. The 1SMB40CAT3G achieves this clamping with sub-1 ns response time and low dynamic impedance.
Is the 1SMB40CAT3G suitable for protecting RS-485 communication lines?
Yes, the 1SMB40CAT3G is suitable for RS-485 line protection due to its bidirectional clamping, 220 pF typical junction capacitance (low enough to avoid signal distortion at ≤10 Mbps), and ability to suppress ESD and fast transients. It is commonly placed between A/B differential pairs and ground. The 1SMB40CAT3G's 40 V VRWM aligns with RS-485 common-mode voltage ranges, and its UL 497B recognition supports use in safety-certified equipment.
Does the 1SMB40CAT3G have automotive qualification?
The base 1SMB40CAT3G is not AEC-Q101 qualified; however, its automotive-grade variant SZ1SMB40CAT3G is fully AEC-Q101 qualified and PPAP capable. Both share identical electrical specifications (VRWM = 40 V, VBR = 44.4–49.1 V, VC = 64.5 V), but only SZ1SMB40CAT3G meets automotive process and traceability requirements. For non-automotive industrial use, the 1SMB40CAT3G remains appropriate and cost-optimized.
What is the thermal derating behavior of the 1SMB40CAT3G at elevated ambient temperatures?
The 1SMB40CAT3G has a DC power dissipation rating of 0.55 W at TA = 25°C, derating linearly by 4.4 mW/°C above that temperature. At 75°C ambient, its usable DC power drops to ~0.33 W. For surge conditions, peak power remains 600 W at TL = 25°C but must be reduced per Figure 3 in the datasheet when lead temperature exceeds 25°C. Proper PCB copper area and airflow are essential to maintain safe junction temperatures during repetitive transients.
How does the 1SMB40CAT3G compare to the P6SMB40A in terms of package and performance?
The 1SMB40CAT3G and P6SMB40A share the same SMB (Case 403C) package, pin-compatible footprint, and nearly identical electrical specs: both have 40 V VRWM, ~49 V VBR, and ~64.5 V clamping voltage. However, the 1SMB40CAT3G is Pb-free and UL 497B recognized, while the P6SMB40A is legacy-lead-based and lacks UL recognition. The 1SMB40CAT3G also features ON Semiconductor's SURMETIC™ molding compound for enhanced moisture resistance and long-term reliability.
1SMB40CAT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AA, SMB
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 9.3A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 220pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB40CAT3G FAQ
1.How can I place an order for 1SMB40CAT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB40CAT3G 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 1SMB40CAT3G reliable?
The price and inventory of 1SMB40CAT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB40CAT3G is usually 5 days.
3.What payment methods are accepted for 1SMB40CAT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB40CAT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB40CAT3G?
1SMB40CAT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB40CAT3G 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 1SMB40CAT3G?
For technical support, including 1SMB40CAT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB40CAT3G requirements.
6.How does Aetrix verify that 1SMB40CAT3G is sourced from the original manufacturer or authorized distributors?
All 1SMB40CAT3G 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 1SMB40CAT3G meets industry standards.
7.What is the process for return or replacement of 1SMB40CAT3G?
All 1SMB40CAT3G units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB40CAT3G, 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 1SMB40CAT3G part is unused and in its original packaging.
Return procedure for 1SMB40CAT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB40CAT3G Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
