Microchip Technology SM8LC15E3/TR13

Overview

SM8LC15E3/TR13 from Microsemi (now Microchip Technology) is a bidirectional transient voltage suppressor (TVS) array in SO-8 package, rated for 500 W peak pulse power (8/20 µs), 15 V standoff voltage (V_WM), and 24 V clamping voltage at 1 A. It provides board-level ESD protection per IEC 61000-4-2 (±15 kV contact), EFT per IEC 61000-4-4, and lightning-induced surge suppression for I/O transceivers.

For engineers reviewing the SM8LC15E3/TR13 datasheet, SM8LC15E3/TR13 pinout, SM8LC15E3/TR13 application, or SM8LC15E3/TR13 equivalent, key selection criteria include standoff voltage matching circuit operating voltage, clamping performance under 1–5 A surge current, low 25 pF line-to-line capacitance for high-speed data integrity, and SO-8 thermal and mechanical compatibility with automated SMT assembly.

Technical Context

This TVS array employs silicon avalanche diode technology in a dual-channel, common-cathode configuration. Each channel protects one bidirectional signal line with symmetrical breakdown (V_BR min = 16.7 V, max = ? V) and matched clamping behavior up to 30 V at 5 A.

Designed for board-edge I/O protection, it operates across –55 °C to +150 °C and maintains ≤1 µA leakage at 15 V standoff. Its 25 pF capacitance per line pair ensures minimal signal distortion on interfaces such as RS-485, USB 2.0, and CAN FD physical layers.

Key Specifications

Pinout & Package

SO-8 surface-mount package (JEDEC MS-012AC), 5.0 mm × 4.0 mm footprint, 1.27 mm pitch, 1.75 mm max height. Pin #1 identified by dot marking on top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ15A and SP1003-010, SM8LC15E3/TR13 uniquely delivers dual-line protection in SO-8 with balanced 25 pF capacitance and 500 W surge capability - enabling compact, standards-compliant I/O hardening without compromising data rate or thermal performance.

Availability

SM8LC15E3/TR13 is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and medical device I/O protection requiring stable component supply and long-term manufacturability.

Supply support for SM8LC15E3/TR13 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

Microsemi (acquired by Microchip Technology in 2018) is a U.S.-based semiconductor company specializing in high-reliability analog, mixed-signal, and radiation-hardened components for aerospace, defense, and industrial markets.

The SM8LCxx TVS array family was engineered specifically for board-level ESD/EFT protection of high-speed differential interfaces, emphasizing low capacitance, precise clamping, and SO-8 manufacturability for automated assembly.

FAQ

What is the standoff voltage rating of SM8LC15E3/TR13 and how does it relate to circuit protection?

The SM8LC15E3/TR13 has a standoff voltage (V_WM) of 15 V, meaning it remains non-conductive below this DC or continuous peak voltage. This value must equal or exceed the maximum operating voltage of the protected line - for example, a 12 V RS-485 bus - to prevent false triggering while ensuring rapid clamping above 16.7 V breakdown. Using SM8LC15E3/TR13 on a 3.3 V interface would cause continuous conduction and failure.

Does SM8LC15E3/TR13 meet IEC 61000-4-2 Level 4 ESD requirements?

Yes, SM8LC15E3/TR13 is characterized to suppress ±15 kV contact discharge per IEC 61000-4-2 Level 4. Its 24 V clamping voltage at 1 A and 30 V at 5 A ensures downstream transceivers see voltages well below typical damage thresholds (e.g., <33 V for most 3.3 V I/O). Test reports confirm pass/fail compliance when mounted per recommended PCB layout with short ground traces.

Can SM8LC15E3/TR13 be used to protect USB 2.0 high-speed (480 Mbps) signals?

No - SM8LC15E3/TR13 is rated for 25 pF line-to-line capacitance, which is suitable for USB 2.0 full-speed (12 Mbps) but causes excessive signal attenuation and jitter at high-speed (480 Mbps) rates. For USB 2.0 HS, a sub-3 pF TVS like SP3012-01UTG is required. SM8LC15E3/TR13 remains appropriate for USB 2.0 FS ports in industrial HMIs and diagnostic tools.

What is the thermal pad (pins 5–8) on SM8LC15E3/TR13 used for, and should it be connected?

Pins 5–8 on SM8LC15E3/TR13 are internal thermal pads, electrically isolated and not connected to any active circuitry. They serve solely for heat dissipation during high-energy transients. While not required for functionality, soldering them to a large copper pour improves thermal response and long-term reliability under repeated surge stress. Do not tie them to signal or ground nets.

How does the common-cathode configuration of SM8LC15E3/TR13 affect PCB layout?

The common-cathode design of SM8LC15E3/TR13 requires both protected lines (e.g., CAN_H and CAN_L) to share a single low-inductance ground path via pins 2 and 4. This minimizes ground loop area and reduces differential-mode noise injection. Layout best practice is to route pins 2 and 4 directly to a dedicated ground plane using multiple vias - avoiding daisy-chained ground traces that increase clamping impedance.