Taiwan Semiconductor Corporation SMDJ90AH

Overview

SMDJ90AH from Taiwan Semiconductor is a unidirectional 3000W surface-mount transient voltage suppressor (TVS) diode in DO-214AB (SMC) package, with 90V working stand-off voltage (VWM), 100–111V breakdown voltage (VBR), and 146V maximum clamping voltage (VC) at 20.5A peak pulse current. It delivers AEC-Q101 qualification and meets ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive load-dump and ESD protection in power rails.

For engineers reviewing the SMDJ90AH datasheet, SMDJ90AH pinout, SMDJ90AH application, or SMDJ90AH equivalent, key selection criteria include clamping performance under 10/1000µs transients, junction temperature derating above 25°C, forward voltage (VF = 3.5V @ 100A), and compliance with automotive EMC immunity standards.

Technical Context

The SMDJ90AH operates as a unidirectional avalanche diode, activated when reverse voltage exceeds its VBR (100–111V), clamping transients to ≤146V at IPPM = 20.5A. Its glass-passivated junction ensures stable breakdown and low leakage (<1µA @ 90V), while thermal resistance RθJA = 75°C/W supports operation up to TJ = 175°C.

Designed for single-pulse surge suppression per IEC 61000-4-5 and ISO 7637-2, it responds in <1.0ps and handles non-repetitive 8.3ms half-sine surges up to 300A (IFSM). Polarity is marked by cathode band; no internal series impedance or integrated control logic is present.

Key Specifications

Pinout & Package

Package: DO-214AB (SMC), surface-mount, matte tin-plated leads, polarity indicated by cathode band on cathode end.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SAC90A and SMCJ90A, the SMDJ90AH provides guaranteed AEC-Q101 qualification and full ISO 7637-2 compliance out-of-box, whereas SAC90A lacks automotive validation and SMCJ90A requires cross-manufacturer layout verification despite identical parametric performance.

Availability

SMDJ90AH is available at Aetrix Electronics and suitable for automotive electronics, industrial power supplies, and telecom infrastructure requiring stable component supply with full AEC-Q101 traceability and ISO 7637-2 compliance.

Supply support for SMDJ90AH 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 analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, MOSFETs, and automotive-qualified components.

The SMDJ series was developed specifically for high-energy transient suppression in harsh automotive and industrial environments, emphasizing robust clamping, fast response, and long-term reliability under thermal cycling and humidity stress.

FAQ

What is the maximum clamping voltage of the SMDJ90AH under standard test conditions?

The SMDJ90AH has a maximum clamping voltage (VC) of 146 V when subjected to a 10/1000 µs transient waveform at a peak pulse current (IPPM) of 20.5 A. This value is measured at TA = 25°C and defines the upper voltage limit imposed on protected circuitry during surge events. The SMDJ90AH maintains this clamping performance consistently across its specified operating temperature range, making it suitable for demanding applications such as automotive power rail protection.

Is the SMDJ90AH suitable for bidirectional transient suppression?

No, the SMDJ90AH is a unidirectional TVS diode and is not rated for bidirectional operation. Its electrical specifications-including breakdown voltage, clamping voltage, and forward voltage-are defined only for reverse-biased (cathode-positive) and forward-conducting (anode-positive) modes. For bidirectional protection, the SMDJ90CAH variant must be used. The SMDJ90AH's cathode band marking confirms its polarity-sensitive placement, and using it in reverse-biased configurations outside its rated parameters may result in failure.

Does the SMDJ90AH meet automotive reliability standards?

Yes, the SMDJ90AH is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test requirements. It undergoes rigorous stress testing including temperature cycling, highly accelerated life testing (HALT), and ESD verification per JESD22-A114. These qualifications confirm its suitability for under-hood and body-control module applications where thermal stability, mechanical robustness, and transient immunity are critical-key attributes validated for the SMDJ90AH across full production lots.

What is the forward voltage drop of the SMDJ90AH at rated surge current?

The SMDJ90AH exhibits a forward voltage (VF) of 3.5 V when conducting 100 A in the forward direction, per the absolute maximum ratings table. This parameter is relevant during fault conditions involving high-current reverse surges that cause the device to conduct forward through its PN junction. The 3.5 V drop impacts power dissipation and thermal design-especially in layouts where forward conduction paths exist-and is confirmed for all SMDJ10AH–SMDJ90AH variants, distinguishing them from the SMDJ100AH (VF = 5.0 V).

How does the SMDJ90AH's thermal performance affect PCB layout?

The SMDJ90AH has a junction-to-ambient thermal resistance (RθJA) of 75°C/W and junction-to-lead resistance (RθJL) of 15°C/W. To maintain TJ ≤ 175°C during repeated surges, PCB layout must maximize copper area connected to both terminals-especially the cathode pad-to exploit RθJL. Minimum recommended pad size follows DO-214AB land pattern guidelines; inadequate copper or thermal vias will cause premature thermal shutdown or parametric shift. This thermal behavior is intrinsic to the SMDJ90AH's silicon die and molding compound, not adjustable via external heatsinking.