Diodes Incorporated SMAT70A-13

Overview

SMAT70A-13 from Diodes Incorporated is a surface-mount transient voltage suppressor (TVS) diode designed for primary overvoltage protection in DC power lines and telecom interfaces. It features a 70 V reverse standoff voltage, 100 V maximum clamping voltage at 3.5 A peak pulse current, 400 W peak pulse power dissipation, and fast sub-picosecond response time - deployed in -48 V backplane telecom systems to absorb lightning-induced surges.

For engineers reviewing the SMAT70A-13 datasheet, SMAT70A-13 pinout, SMAT70A-13 application, or SMAT70A-13 equivalent, key selection criteria include clamping voltage margin relative to protected ICs, I_PP capability under 8.3 ms surge waveforms, thermal derating above 25°C ambient, and SMA package compatibility with high-density PCB layouts.

Technical Context

The SMAT70A-13 operates as a unidirectional avalanche diode with glass-passivated silicon die, triggering conduction when reverse voltage exceeds its 77.8–89.5 V breakdown range at 1 mA test current. Its clamping behavior limits transient energy to ≤100 V at 3.5 A (8.3 ms half-sine), enabling robust protection of downstream 75 V-rated interface circuitry.

Designed for single-pulse, non-repetitive surge events, it follows JEDEC-standard I_FSM testing (40 A, 8.3 ms) and exhibits <5 µA reverse leakage at 70 V. The device's junction capacitance is 55 pF at 0 VDC and 1 MHz, making it suitable for low-speed power-line protection rather than high-frequency signal lines.

Key Specifications

Pinout & Package

SMAT70A-13 is housed in an SMA (DO-214AC) surface-mount package with cathode-banded polarity marking. The two-terminal device has no internal logic or control pins - Terminal 1 (cathode) connects to the protected line, Terminal 2 (anode) to ground or return path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBT70A-13 and P6SMB70A, SMAT70A-13 offers optimal space efficiency in high-density telecom boards while maintaining full 70 V standoff and 100 V clamping compliance - ideal where SMA footprint and 400 W surge handling meet design requirements.

Availability

SMAT70A-13 is available at Aetrix Electronics and suitable for telecom backplane protection, industrial PLC power inputs, and automotive body control modules requiring stable component supply and consistent surge performance across production batches.

Supply support for SMAT70A-13 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability protection, power management, and signal integrity solutions for industrial and communications markets.

The SMAT70A-13 belongs to Diodes' TVS Diode portfolio, engineered specifically for cost-sensitive, high-volume surge protection in DC-fed infrastructure equipment where compact size and repeatable clamping performance are critical.

FAQ

What is the maximum clamping voltage of SMAT70A-13 and under what test condition is it specified?

The maximum clamping voltage is 100 V, measured at a peak pulse current (I_PP) of 3.5 A using an 8.3 ms single half-sine waveform per JEDEC standards. This value represents the worst-case voltage imposed on protected circuitry during a defined surge event and is guaranteed across the full operating temperature range.

Does SMAT70A-13 have polarity sensitivity, and how is it marked on the device?

Yes, SMAT70A-13 is a unidirectional TVS diode with cathode-anode polarity. It is marked with a distinct cathode band on the SMA package body, aligned with the cathode terminal. Correct orientation is essential: cathode must connect to the line being protected, anode to ground, to ensure proper clamping action during reverse transients.

Can SMAT70A-13 be used in AC-coupled signal lines?

No - SMAT70A-13 is unidirectional and optimized for DC power-line protection. Its 55 pF junction capacitance and lack of symmetrical bidirectional clamping make it unsuitable for high-speed or AC signal paths. For data lines, bidirectional TVS arrays like D3V3Z5 or SP1003 are recommended instead.

How does ambient temperature affect the surge capability of SMAT70A-13?

Peak pulse power and current ratings are derated linearly above 25°C ambient, per the published derating curve (Fig. 1 in DS30213). At 85°C, SMAT70A-13 retains approximately 65% of its 400 W rating - i.e., ~260 W - requiring thermal layout review in enclosed or high-power-density applications.