Taiwan Semiconductor Corporation SMBJ45H

Overview

SMBJ45H from Taiwan Semiconductor is a unidirectional 45 V working stand-off voltage transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, rated for 600 W peak pulse power, 80.3 V maximum clamping voltage at 7.8 A peak impulse current, and <1 µA leakage above 10 V. It protects automotive and industrial power rails against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.

For engineers reviewing the SMBJ45H datasheet, SMBJ45H pinout, SMBJ45H application, or SMBJ45H equivalent, key selection criteria include clamping voltage margin relative to protected IC V_MAX, unidirectional polarity alignment with DC rail direction, thermal derating above 25°C ambient, and AEC-Q101 qualification for under-hood deployment.

Technical Context

The SMBJ45H operates as a silicon avalanche diode with glass-passivated junction, delivering sub-1 ps response time to fast EFT and load-dump transients. Its breakdown voltage is specified at 50.0–61.1 V with 1 mA test current, and it maintains <1 µA blocking leakage at its 45 V V_WM.

Designed for surface-mount automated placement, it meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability. Thermal resistance is 10 °C/W (junction-to-case) and 55 °C/W (junction-to-ambient), supporting sustained 3 W steady-state dissipation at 25°C.

Key Specifications

Pinout & Package

DO-214AA (SMB) surface-mount package with cathode band marking; matte tin-plated leads compliant with J-STD-002 solderability; polarity-sensitive unidirectional configuration.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient suppression applications.

Compared with SMBJ45A and SAC45, the SMBJ45H offers the highest peak power handling (600 W) in compact DO-214AA packaging, making it optimal for space-constrained automotive modules where both clamping performance and layout density matter.

Availability

SMBJ45H is available at Aetrix Electronics and suitable for automotive ECU design, industrial sensor interface protection, and LED driver input stage hardening requiring stable component supply and AEC-Q101 traceability.

Supply support for SMBJ45H 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs with global distribution and AEC-Q101 certification capability.

The SMBJH series was developed specifically for automotive and industrial transient suppression, emphasizing robustness against ISO 7637-2 pulses, high-temperature operation, and automated assembly compatibility.

FAQ

What is the maximum clamping voltage of SMBJ45H under standard test conditions?

The SMBJ45H has a maximum clamping voltage (V_C) of 80.3 V when subjected to a 10/1000 µs waveform peak impulse current (I_PP) of 7.8 A at T_A = 25°C. This value is measured across the device terminals and defines the upper voltage limit imposed on protected circuitry during surge events. The SMBJ45H maintains this clamping performance within its specified junction temperature range of –55°C to +150°C.

Is SMBJ45H suitable for bidirectional transient protection?

No, SMBJ45H is a unidirectional TVS diode intended for DC circuits with defined polarity. For bidirectional protection, Taiwan Semiconductor offers the SMBJ45CH variant (with CH suffix), which provides symmetrical clamping in both directions. Using SMBJ45H in AC or bipolar applications risks failure due to forward conduction during negative half-cycles. Always verify polarity alignment before deploying SMBJ45H in the target system.

Does SMBJ45H meet automotive qualification standards?

Yes, SMBJ45H is AEC-Q101 qualified and tested per the full stress test schedule including HTGB, H3TRB, TC, UHAST, and mechanical shock. It also complies with ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b for automotive electrical disturbance immunity. These qualifications confirm its suitability for under-hood and body-control module applications where reliability under thermal, vibration, and electrical stress is critical. SMBJ45H is not rated for safety-critical functions like airbag or brake control.

What is the thermal resistance profile of SMBJ45H?

SMBJ45H exhibits a junction-to-case thermal resistance (R_θJC) of 10 °C/W and a junction-to-ambient thermal resistance (R_θJA) of 55 °C/W under standard JEDEC test conditions. These values enable 3 W steady-state power dissipation at 25°C ambient, with linear derating above that temperature per Figure 2 in the datasheet. PCB copper area and airflow significantly influence actual R_θJA; for high-power transient duty cycles, thermal simulation is recommended to ensure T_J remains below 150°C.

How does SMBJ45H compare to SMBJ45A in terms of breakdown voltage tolerance?

SMBJ45H specifies a breakdown voltage (V_BR) range of 50.0–61.1 V at I_T = 1 mA, while SMBJ45A narrows this to 50.0–55.3 V. This tighter tolerance reduces variation in clamping onset across production lots, improving consistency in systems where precise overvoltage thresholding is required. Both parts share identical V_WM (45 V), package (DO-214AA), and AEC-Q101 qualification. SMBJ45H remains preferred when maximum surge energy absorption is the priority.