onsemi SMCJ58A

Overview

SMCJ58A from Fairchild Semiconductor is a unidirectional 1500 W transient voltage suppressor (TVS) diode designed for primary-level overvoltage protection in DC power lines and signal interfaces. It features a 58 V reverse stand-off voltage (VRWM), 64.4–71.2 V breakdown voltage (VBR) at 1 mA, 93.6 V clamping voltage (VC) at 16.0 A peak pulse current, and UL94V-0 flammability rating - deployed in industrial motor drives to protect IGBT gate drivers from inductive switching transients.

For engineers reviewing the SMCJ58A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 10/1000 μs surge, low incremental surge resistance, fast response time (<1.0 ps), reverse leakage ≤5 μA at VRWM, and compatibility with SMC/DO-214AB surface-mount layout constraints.

Technical Context

The SMCJ58A operates as a unidirectional avalanche diode with glass-passivated junction construction, enabling robust surge handling without degradation under repeated 1500 W pulses. Its clamping behavior is defined by a tightly controlled VBR range (64.4–71.2 V) and low dynamic impedance, ensuring predictable voltage limiting during ESD or lightning-induced transients.

Designed for single-pulse suppression per JEDEC-standard 10/1000 μs waveform, it supports non-repetitive forward surge current up to 200 A (8.3 ms half-sine) and maintains junction temperature ≤150°C. The cathode band marking confirms polarity for correct PCB orientation in series-connected protection circuits.

Key Specifications

Pinout & Package

SMCJ58A uses the SMC/DO-214AB surface-mount package: a rectangular body with cathode indicated by a color band on the unidirectional variant. No band denotes bidirectional types (e.g., SMCJ58CA); SMCJ58A includes the band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ58A, SMBJ58A offers reduced surge capacity in a smaller SMB package, while SMCJ58CA provides polarity-agnostic clamping at identical power rating - selection depends strictly on surge energy level and signal polarity requirements, not pin compatibility.

Availability

SMCJ58A is available at Aetrix Electronics and suitable for industrial motor drives, telecom power feeds, and renewable energy inverters requiring stable component supply with consistent surge performance and UL-certified reliability.

Supply support for SMCJ58A 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

Fairchild Semiconductor was a leading designer of high-performance analog and discrete semiconductors, acquired by ON Semiconductor in 2016; its legacy TVS portfolio remains widely deployed in industrial and infrastructure applications.

The SMCJ series was engineered specifically for high-power, surface-mount transient suppression in harsh environments - targeting applications demanding >1000 W surge capability, tight VBR tolerance, and UL certification compliance.

FAQ

What is the clamping voltage of SMCJ58A at its rated peak pulse current?

The SMCJ58A has a maximum clamping voltage (VC) of 93.6 V at its rated peak pulse current (IPPM) of 16.0 A under the standard 10/1000 μs waveform. This value is measured per JEDEC test conditions and ensures predictable overvoltage limiting for downstream components. The SMCJ58A achieves this clamping performance while maintaining low dynamic impedance, making it suitable for protecting sensitive gate drivers and power ICs in high-noise environments.

Is SMCJ58A unidirectional or bidirectional, and how is polarity identified?

SMCJ58A is a unidirectional transient voltage suppressor, indicated by a visible cathode band on the device body. Bidirectional variants carry the "C" suffix (e.g., SMCJ58CA) and lack the band. The SMCJ58A conducts only during reverse-biased overvoltage events and must be oriented with cathode toward ground in shunt protection configurations. Correct polarity identification is critical - misplacement renders the SMCJ58A ineffective against positive-going transients.

What is the maximum operating junction temperature for SMCJ58A?

The SMCJ58A has a maximum operating junction temperature (TJ) of 150°C, as specified in Fairchild's absolute maximum ratings. This allows reliable operation in high-ambient environments such as enclosed motor drive cabinets or outdoor telecom enclosures. Thermal design must ensure that power dissipation during surge events does not cause sustained junction temperatures beyond this limit - the SMCJ58A is rated for non-repetitive pulses, not continuous power dissipation.

Does SMCJ58A meet UL safety certification requirements?

Yes, the SMCJ58A carries UL Certificate #E258596 and complies with UL94V-0 flammability standards. This certification validates its ability to withstand flame propagation during fault conditions - a mandatory requirement for end equipment sold in North America and many industrial markets. The UL listing applies specifically to the SMCJ58A device, not the broader SMCJ family, and confirms compliance under standardized test protocols for transient suppressors.

Can SMCJ58A be used in place of SMCJ58CA in a bidirectional signal line?

No, SMCJ58A cannot replace SMCJ58CA in bidirectional signal lines such as RS-485 or CAN bus. The SMCJ58A is unidirectional and only clamps negative transients relative to its cathode; it offers no protection against positive excursions on the anode side. Using SMCJ58A in place of SMCJ58CA would leave the line vulnerable to half the surge spectrum. The SMCJ58CA's symmetrical breakdown and clamping behavior is essential for AC-coupled or floating interfaces where voltage polarity reverses.