Vishay General Semiconductor - Diodes Division SMAJ17CAHE3/5A

Overview

SMAJ17CAHE3/5A from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection of sensitive electronics. It features a 17 V standoff voltage (V_WM), 18.9–20.9 V breakdown voltage (V_BR) at 1 mA, and clamps transients to ≤27.6 V at 14.5 A peak pulse current (I_PPM) under 10/1000 μs waveform - deployed on power rails and signal lines in automotive ECUs and industrial sensor interfaces.

For engineers reviewing the SMAJ17CAHE3/5A datasheet, SMAJ17CAHE3/5A pinout, SMAJ17CAHE3/5A application, or SMAJ17CAHE3/5A equivalent, this AEC-Q101 qualified, RoHS-compliant TVS delivers 400 W peak pulse power (≤78 V), low clamping ratio (VC/VBR ≈ 1.45), and MSL Level 1 reflow compatibility - critical for high-reliability board-level surge protection design and ESD/inductive switching transient mitigation.

Technical Context

This bidirectional TVS operates symmetrically across both polarities, with identical V_BR, V_C, and I_PPM specifications in forward and reverse directions. Its glass-passivated junction ensures stable avalanche characteristics and fast response time (<1 ps), enabling effective suppression of EFT (IEC 61000-4-4) and lightning-induced surges (IEC 61000-4-5).

Thermal performance is defined by R_θJA = 120 °C/W (on 0.2" × 0.2" copper pads) and R_θJL = 30 °C/W, supporting continuous operation up to T_J = 150 °C. The device meets JESD201 Class 2 whisker resistance and UL 497B recognition (QVGQ2), confirming suitability for automotive and industrial safety-critical circuits.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002 and JESD22-B102. Bidirectional configuration has no polarity marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ17CA-E3/5A, the SMAJ17CAHE3/5A adds automotive qualification without electrical trade-offs; versus SMBJ17CAHE3/5A, it trades thermal robustness for space-constrained routing - making it optimal for AEC-Q101-compliant, size-sensitive CAN/LIN node designs.

Availability

SMAJ17CAHE3/5A is available at Aetrix Electronics and suitable for automotive ECUs, industrial sensor interfaces, and telecom line card protection requiring stable component supply across multi-year production cycles.

Supply support for SMAJ17CAHE3/5A 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

Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in high-reliability diodes, MOSFETs, and optoelectronics for automotive, industrial, and computing markets.

The SMAJ series targets board-level transient protection in harsh environments, with AEC-Q101 variants engineered specifically for automotive subsystems demanding zero-failure field performance.

FAQ

What is the clamping voltage of SMAJ17CAHE3/5A at its rated peak pulse current?

The SMAJ17CAHE3/5A clamps to a maximum of 27.6 V at its specified peak pulse current of 14.5 A under the 10/1000 μs waveform. This value is measured per IEC 61000-4-5 test conditions and ensures downstream components see limited overvoltage stress. The clamping ratio (V_C/V_BR) is approximately 1.45, confirming efficient energy diversion. This performance is guaranteed across the full operating temperature range of −55 °C to +150 °C.

Is SMAJ17CAHE3/5A suitable for protecting CAN FD interfaces?

Yes, SMAJ17CAHE3/5A is well-suited for CAN FD interface protection due to its bidirectional symmetry, low 10 pF typical junction capacitance at 0 V, and fast sub-nanosecond response. Its 17 V standoff voltage aligns with CAN FD's 5 V differential swing and 12 V common-mode range, while clamping at 27.6 V prevents transceiver damage during ISO 11898-2 transient events. The AEC-Q101 qualification further validates its use in automotive CAN FD nodes.

Does SMAJ17CAHE3/5A require a heatsink for standard surge duty cycles?

No, SMAJ17CAHE3/5A does not require an external heatsink for standard single-pulse or low-duty-cycle surge events (e.g., IEC 61000-4-5, ISO 7637-2). Its R_θJA of 120 °C/W is sufficient when mounted on minimum recommended 0.2" × 0.2" copper pads. However, for repetitive surges above 0.01% duty cycle or ambient temperatures exceeding 85 °C, thermal simulation using R_θJL = 30 °C/W is advised to ensure T_J remains below 150 °C.

How does the HE3 suffix affect the reliability of SMAJ17CAHE3/5A?

The HE3 suffix on SMAJ17CAHE3/5A denotes RoHS-compliant construction with AEC-Q101 qualification - meaning the device undergoes extended stress testing including temperature cycling, high-temperature reverse bias (HTRB), and ESD per JS-001. This results in demonstrated field failure rates <10 FIT and validated performance across −55 °C to +150 °C junction temperature. The HE3 variant is mandatory for Tier 1 automotive production where PPAP compliance is required.

Can SMAJ17CAHE3/5A be used in place of a unidirectional TVS like SMAJ17AHE3/5A?

No - SMAJ17CAHE3/5A is strictly bidirectional and lacks polarity marking, whereas SMAJ17AHE3/5A is unidirectional with a cathode band and conducts only in reverse bias. Substituting one for the other risks improper clamping in DC-biased circuits (e.g., 5 V logic rails), where unidirectional devices block forward leakage but bidirectional types conduct in both directions. Always match device polarity to circuit topology; SMAJ17CAHE3/5A is intended for AC-coupled or differential lines like CAN, RS-485, or antenna feeds.