Taiwan Semiconductor Corporation SMDJ30AH

Overview

SMDJ30AH from Taiwan Semiconductor is a unidirectional 3000W surface-mount transient voltage suppressor (TVS) diode in DO-214AB (SMC) package, with 33.3V minimum breakdown voltage (V_BR), 30V working stand-off voltage (V_WM), and 48.4V maximum clamping voltage (V_C) at 62A peak pulse current. It delivers AEC-Q101 qualification, ISO 7637-2 compliance for automotive transients, and sub-1ps response time for ESD and load-switching surge protection in power rails.

For engineers reviewing the SMDJ30AH datasheet, SMDJ30AH pinout, SMDJ30AH application, or SMDJ30AH equivalent, key selection criteria include clamping performance under 10/1000μs waveform, thermal resistance (R_θJA = 75°C/W), unidirectional polarity marking, and compatibility with automated SMT placement per J-STD-002 solderability standards.

Technical Context

The SMDJ30AH operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology to achieve stable reverse-biased clamping during fast transients. Its 33.3–36.8V V_BR range at 1mA test current ensures precise overvoltage thresholding, while the 48.4V V_C at 62A IPPM defines its energy-handling capability under standardized 10/1000μs pulses.

Designed for automotive-grade reliability, it meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b waveforms and supports junction temperatures from –55°C to +175°C. Its DO-214AB package enables high-power dissipation (3000W peak, 6.5W steady-state) with R_θJL = 15°C/W for efficient lead-to-junction heat transfer.

Key Specifications

Pinout & Package

Package: DO-214AB (SMC), surface-mount, unidirectional configuration with cathode band marking. Matte tin-plated leads, UL 94V-0 molding compound, 0.290g weight.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SAC30-13-F and 1.5SMC33A, the SMDJ30AH offers tighter clamping (48.4V vs. ≥50.4V), AEC-Q101 validation, and guaranteed ISO 7637-2 compliance-making it the preferred choice for automotive and safety-critical 24V/30V rail protection where voltage margin is constrained.

Availability

SMDJ30AH is available at Aetrix Electronics and suitable for automotive ECU power protection, industrial PLC I/O hardening, and telecom DC input surge suppression requiring stable component supply across production lifecycles.

Supply support for SMDJ30AH 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-compliant production lines.

The SMDJ series is engineered specifically for high-energy transient suppression in harsh environments-targeting automotive, industrial, and telecom applications where reliability under ISO 7637-2 and extended temperature operation are mandatory.

FAQ

What is the clamping voltage of the SMDJ30AH and how is it measured?

The SMDJ30AH has a maximum clamping voltage (V_C) of 48.4 V, measured at a peak pulse current (I_PPM) of 62 A under the standardized 10/1000 μs double-exponential waveform per IEC 61000-4-5. This value is guaranteed across the full operating temperature range and reflects the actual voltage imposed on protected circuitry during worst-case surge events. The SMDJ30AH maintains this clamping performance due to its glass-passivated junction and low dynamic impedance.

Is the SMDJ30AH suitable for automotive applications?

Yes, the SMDJ30AH is AEC-Q101 qualified and explicitly designed for automotive use. It meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b transient immunity requirements and operates reliably from –55°C to +175°C. Its DO-214AB package supports automated SMT assembly, and its moisture sensitivity level (MSL) is Level 1-eliminating bake requirements prior to reflow. These attributes make the SMDJ30AH appropriate for engine control units, body control modules, and ADAS power supplies.

What is the difference between SMDJ30AH and SMDJ30CAH?

The SMDJ30AH is unidirectional, while the SMDJ30CAH is bidirectional-meaning the latter clamps in both polarities and lacks an anode/cathode distinction. The SMDJ30AH has a forward voltage (V_F) of 3.5 V at 100 A, whereas the SMDJ30CAH does not specify V_F due to symmetrical structure. Both share identical V_WM (30 V), V_BR (33.3–36.8 V), and V_C (48.4 V) ratings. Use SMDJ30AH for DC rails with defined polarity; choose SMDJ30CAH for AC-coupled or floating signal lines.

Does the SMDJ30AH require derating at elevated ambient temperatures?

Yes, the SMDJ30AH must be derated above 25°C ambient per its pulse derating curve (Fig.2). At 85°C ambient, its 3000W peak pulse power rating drops to approximately 1800W; at 125°C, it falls to ~1000W. Steady-state power dissipation (P_D) is fixed at 6.5W regardless of temperature. Proper PCB layout-including ≥1 cm² of 2-oz copper connected to both leads-is essential to maintain thermal performance and avoid exceeding T_J = +175°C during repeated surges.

How is polarity marked on the SMDJ30AH package?

The SMDJ30AH uses a cathode band (dark stripe) on the DO-214AB (SMC) case to indicate the cathode terminal. This band aligns with the cathode end of the internal die and must be oriented toward the higher-potential side of the protected line (e.g., connected to V_BAT). The anode is the opposite end, typically connected to ground or return. Polarity is confirmed in the Marking Diagram section of the datasheet and verified via continuity test: forward bias (anode positive) yields ~3.5 V drop at 100 A; reverse bias shows high impedance until V_BR is exceeded.