Alpha & Omega Semiconductor Inc. SMDJ36A

Overview

SMDJ36A from Alpha & Omega Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy surge protection in DC power lines and signal interfaces. It features a 36 V reverse stand-off voltage (VRWM), 40–44.2 V breakdown voltage (VBR) at 1 mA, 58.1 V maximum clamping voltage (VC) at 51.7 A peak pulse current, and 3000 W peak pulse power dissipation on a 10/1000 µs waveform - deployed in industrial motor drives to protect IGBT gate drivers from inductive switching transients.

For engineers reviewing the SMDJ36A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 10/1000 µs surges, thermal resistance (RθJL = 15 °C/W), unidirectional polarity with cathode band marking, DO-214AB package compatibility, and compliance with J-STD-020 MSL Level 1 reflow requirements.

Technical Context

The SMDJ36A operates as a silicon avalanche diode optimized for fast transient suppression. Its glass-passivated junction enables sub-1 ps response time from 0 V to breakdown, while its low-profile DO-214AB (SMC J-Bend) package supports high-density PCB layouts and meets UL 94V-0 flammability standards.

Designed for non-repetitive surge events at ≤0.01% duty cycle, it delivers 3000 W peak pulse power when mounted on 8.0 mm × 8.0 mm copper pads per terminal. Thermal management relies on RθJA = 75 °C/W (ambient) and RθJL = 15 °C/W (lead), enabling reliable operation across -55 °C to +150 °C junction temperature range.

Key Specifications

Pinout & Package

DO-214AB (SMC J-Bend) package: molded plastic case with matte tin lead-free plating, color band denoting cathode (anode is unmarked). Terminals are solderable per MIL-STD-750 Method 2026. Mounting requires 8.0 mm × 8.0 mm copper pads per terminal for rated PPPM performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SAC36A and 1.5KE36A, the SMDJ36A offers superior thermal performance in SMT layouts (RθJL = 15 °C/W), full MSL1 reflow readiness, and tighter VBR tolerance (±5.5%), making it optimal for automated manufacturing of compact industrial and automotive electronics.

Availability

SMDJ36A is available at Aetrix Electronics and suitable for industrial motor drives, DC power supply inputs, and automotive body control modules requiring stable component supply, RoHS-compliant packaging, and traceable sourcing for long-lifecycle programs.

Supply support for SMDJ36A 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

Alpha & Omega Semiconductor (AOS) is a fabless power semiconductor company specializing in high-efficiency MOSFETs, TVS diodes, and power ICs for computing, consumer, industrial, and automotive markets.

The SMDJ series is engineered for robust transient suppression in high-power surface-mount applications, targeting design-in where space-constrained PCBs demand high-peak-power TVS devices with repeatable clamping and JEDEC-standard reflow compatibility.

FAQ

What is the clamping voltage of the SMDJ36A under maximum rated surge current?

The SMDJ36A exhibits a maximum clamping voltage (VC) of 58.1 V when subjected to its rated peak pulse current (IPPM) of 51.7 A on a 10/1000 µs waveform. This value is measured at 25 °C ambient and assumes mounting on 8.0 mm × 8.0 mm copper pads per terminal. The SMDJ36A maintains this clamping performance across its operational junction temperature range, making it suitable for protecting sensitive 3.3 V, 5 V, and 12 V logic interfaces in harsh environments.

Is the SMDJ36A suitable for bidirectional surge protection?

No, the SMDJ36A is a unidirectional TVS diode, indicated by the "A" suffix and single cathode band marking. For bidirectional operation, the correct variant is SMDJ36CA (with "CA" suffix), which provides symmetrical clamping in both polarities. Using SMDJ36A in a bidirectional configuration risks failure during negative-going transients, as it will not conduct below its forward voltage drop (~0.7 V) in reverse bias.

What is the thermal resistance from junction to ambient for the SMDJ36A?

The SMDJ36A has a typical junction-to-ambient thermal resistance (RθJA) of 75 °C/W when mounted on standard FR-4 PCB with 8.0 mm × 8.0 mm copper pads per terminal. This value assumes still air convection and defines the steady-state temperature rise per watt of power dissipated. For pulsed operation, junction temperature rise is dominated by transient thermal impedance rather than RθJA, allowing safe handling of 3000 W peaks despite the relatively high RθJA.

Does the SMDJ36A meet lead-free reflow requirements?

Yes, the SMDJ36A is qualified to MSL Level 1 per J-STD-020 and supports peak reflow temperatures up to 260 °C. Its matte tin lead-free plating and DO-214AB package are fully compatible with standard Pb-free soldering profiles. The device is also RoHS compliant and halogen-free per AOS Green Policy, making it suitable for global electronics manufacturing without exemption requests.

How does the SMDJ36A compare to older SMAJ36A in terms of surge capability?

The SMDJ36A delivers 3000 W peak pulse power, doubling the 1500 W rating of the SMAJ36A (DO-214AC package). Its larger DO-214AB body improves thermal mass and lowers RθJL to 15 °C/W (vs. ~25 °C/W for SMAJ), enabling higher surge repetition resilience. Both share identical VRWM and VBR ranges, but SMDJ36A's enhanced power handling makes it preferred for industrial inverters and EV charging systems where sustained surge exposure occurs.