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Home > Products > Circuit Protection > Transient Voltage Suppressors (TVS) > TVS Diodes

Taiwan Semiconductor Corporation SMAJ64CH

Name: SMAJ64CH
Brand: Taiwan Semiconductor Corporation
SKU: SMAJ64CH
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SMAJ64CH

Manufacturer:: Taiwan Semiconductor Corporation

Category:: TVS Diodes

Package:: DO-214AC, SMA

Datasheet:: SMAJ64CH.pdf

Description:: TVS DIODE 64VWM 114VC DO214AC

Quantity:: RFQ Add To RFQ list

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Inventory:4,835

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Product details

Overview

SMAJ64CH from Taiwan Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for automotive-grade overvoltage protection. It features a 64 V working stand-off voltage (V_WM), 71.1–86.9 V breakdown voltage (V_BR), 114 V maximum clamping voltage (V_C) at 3.5 A peak pulse current, and 400 W peak pulse power (10/1000 µs). It is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1/2a/2b/3a/3b for robust vehicle electrical system protection.

For engineers reviewing the SMAJ64CH datasheet, SMAJ64CH pinout, SMAJ64CH application, or SMAJ64CH equivalent, this device is selected for high-reliability DC bus protection in automotive power modules, on-board DC/DC converters, and lighting control units where fast clamping (<1 ps response), low leakage (<1 µA at V_WM), and bidirectional surge immunity are critical.

Technical Context

The SMAJ64CH implements a glass-passivated silicon junction optimized for unidirectional or bidirectional transient suppression. Its bidirectional configuration (denoted by "CH" suffix) ensures symmetrical clamping in both polarities, with identical V_BR, V_C, and I_PPM specifications across forward and reverse directions. The device operates within –55 °C to +150 °C junction temperature range and supports steady-state power dissipation of 1 W.

It complies with JESD201 Class 2 whisker resistance and moisture sensitivity level 1 (per J-STD-020), enabling compatibility with lead-free reflow processes. The 10/1000 µs waveform rating reflects its capability to absorb standardized automotive load-dump and inductive-switching transients without degradation.

Key Specifications

Parameter	Value and Actual Design Meaning
V_WM	64 V - Maximum continuous reverse operating voltage before clamping initiates
V_BR @ I_T = 1 mA	71.1–86.9 V - Breakdown threshold range ensuring reliable turn-on under surge conditions
V_C @ I_PPM = 3.5 A	114 V - Clamped voltage during 10/1000 µs transient, limiting downstream stress
P_PPM	400 W - Peak pulse power handling per single non-repetitive event
I_R @ V_WM	<1 µA - Minimal leakage current preserving system efficiency in standby
T_J Range	–55 °C to +150 °C - Full operational range suitable for under-hood automotive environments

Pinout & Package

DO-214AC (SMA) surface-mount package with cathode band marking; dual-terminal construction with no polarity distinction for bidirectional operation - terminals are functionally symmetric.

Pin/Terminal	Circuit Role	Design Meaning
Anode/Cathode (bidirectional)	Surge current path terminal	Either terminal accepts transient energy in either polarity; no fixed anode/cathode assignment
Cathode band (marking)	Reference orientation marker	Indicates physical case orientation only; does not define polarity in CH-series bidirectional devices

Key Features

Feature	Design Value
AEC-Q101 qualification	Validated for automotive electronics per stress test requirements including HTOL, TC, UHAST, and ESD
Glass passivated junction	Enhances long-term reliability and stability of V_BR under thermal cycling and humidity exposure
ISO 7637-2 compliance	Guarantees immunity to standardized automotive transients (Pulse 1, 2a, 2b, 3a, 3b) without external circuitry
Fast response time	<1.0 ps from 0 V to V_BR,min - limits voltage overshoot before clamping engages
Halogen-free & RoHS	Meets IEC 61249-2-21 and EU RoHS Directive - supports environmentally compliant manufacturing

Applications

Automotive Lighting Control	On-Board DC/DC Converter
Use Scenario: Protecting LED driver ICs and MOSFET gate drivers from load dump and inductive kickback in headlamp and tail lamp modules. IC Role / Device Role / Timing Role: Bidirectional TVS placed across input rails to clamp transients before they reach sensitive control logic. Use Value: Prevents latch-up or permanent damage to 5 V/3.3 V logic supplies while maintaining <1 µA leakage at 64 V nominal bus.	Use Scenario: Safeguarding primary-side controller and secondary-side feedback circuitry in 12 V-to-5 V/3.3 V isolated DC/DC converters. IC Role / Device Role / Timing Role: Transient suppressor connected between input rail and ground, absorbing 10/1000 µs pulses up to 400 W. Use Value: Enables stable operation under ISO 7637-2 Pulse 2b (battery disconnect) with clamping limited to 114 V.
Engine Control Unit (ECU) Power Input	Body Control Module (BCM) CAN Bus Interface
Use Scenario: Front-end protection for 5 V/3.3 V LDO regulators powering microcontrollers in engine management systems. IC Role / Device Role / Timing Role: Primary overvoltage guard on main 12 V supply line entering ECU housing. Use Value: Withstands repeated load-dump events (up to 120 V) while holding clamping voltage ≤114 V at 3.5 A peak.	Use Scenario: Secondary-level protection for CAN transceiver power pins against coupled transients from adjacent high-current circuits. IC Role / Device Role / Timing Role: Low-leakage TVS placed between V_CC and GND of CAN PHY to limit voltage excursions during EMC testing. Use Value: Provides bidirectional clamping without affecting CAN signal integrity due to minimal junction capacitance and sub-µA leakage.

Automotive Lighting Control

On-Board DC/DC Converter

Use Scenario: Protecting LED driver ICs and MOSFET gate drivers from load dump and inductive kickback in headlamp and tail lamp modules.

IC Role / Device Role / Timing Role: Bidirectional TVS placed across input rails to clamp transients before they reach sensitive control logic.

Use Value: Prevents latch-up or permanent damage to 5 V/3.3 V logic supplies while maintaining <1 µA leakage at 64 V nominal bus.

Use Scenario: Safeguarding primary-side controller and secondary-side feedback circuitry in 12 V-to-5 V/3.3 V isolated DC/DC converters.

IC Role / Device Role / Timing Role: Transient suppressor connected between input rail and ground, absorbing 10/1000 µs pulses up to 400 W.

Use Value: Enables stable operation under ISO 7637-2 Pulse 2b (battery disconnect) with clamping limited to 114 V.

Engine Control Unit (ECU) Power Input

Body Control Module (BCM) CAN Bus Interface

Use Scenario: Front-end protection for 5 V/3.3 V LDO regulators powering microcontrollers in engine management systems.

IC Role / Device Role / Timing Role: Primary overvoltage guard on main 12 V supply line entering ECU housing.

Use Value: Withstands repeated load-dump events (up to 120 V) while holding clamping voltage ≤114 V at 3.5 A peak.

Use Scenario: Secondary-level protection for CAN transceiver power pins against coupled transients from adjacent high-current circuits.

IC Role / Device Role / Timing Role: Low-leakage TVS placed between V_CC and GND of CAN PHY to limit voltage excursions during EMC testing.

Use Value: Provides bidirectional clamping without affecting CAN signal integrity due to minimal junction capacitance and sub-µA leakage.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SMAJ64AHE3/5BT	Unidirectional variant with lower V_BR (71.1–78.6 V); same package and P_PPM	Requires explicit polarity alignment; unsuitable for AC-coupled or floating-bus protection	Select SMAJ64AHE3/5BT only when circuit topology guarantees unidirectional surge direction and tighter V_BR tolerance is needed.
SMCJ64CA	Higher P_PPM (1500 W), larger DO-214AB (SMB) package, same V_WM/V_C specs	Used where higher single-pulse energy absorption is required, e.g., alternator output lines	Choose SMCJ64CA when system-level surge tests exceed 400 W; accept larger footprint and higher cost for enhanced ruggedness.

Compared with SMAJ64AHE3/5BT and SMCJ64CA, the SMAJ64CH uniquely balances AEC-Q101 compliance, bidirectional symmetry, compact DO-214AC footprint, and precise 64 V stand-off - making it optimal for space-constrained automotive modules requiring polarity-agnostic protection.

Availability

SMAJ64CH is available at Aetrix Electronics and suitable for automotive lighting control, on-board DC/DC converter design, and engine control unit (ECU) power input protection requiring stable component supply across production lifecycles.

Supply support for SMAJ64CH 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, and power MOSFETs for automotive and industrial markets.

The SMAJ series was developed specifically for AEC-Q101-compliant transient suppression in 12 V/24 V automotive subsystems, emphasizing fast response, low leakage, and robust ISO 7637-2 immunity in compact surface-mount packages.

FAQ

What does the "CH" suffix indicate in SMAJ64CH?

The "CH" suffix in SMAJ64CH denotes a bidirectional configuration - meaning the device provides symmetrical transient suppression in both forward and reverse directions. Unlike unidirectional variants (e.g., SMAJ64AH), SMAJ64CH has identical breakdown and clamping characteristics regardless of voltage polarity applied across its terminals, making it ideal for floating or AC-coupled bus protection without polarity concerns.

Is SMAJ64CH compatible with lead-free reflow soldering processes?

Yes, SMAJ64CH is fully compatible with lead-free reflow soldering. Its matte tin-plated leads meet J-STD-002 solderability requirements, and its DO-214AC (SMA) package is rated for moisture sensitivity level 1 (per J-STD-020), eliminating bake requirements prior to assembly. The device withstands peak reflow temperatures up to 260 °C per JEDEC J-STD-020.

How does SMAJ64CH meet ISO 7637-2 Pulse 2b requirements?

SMAJ64CH meets ISO 7637-2 Pulse 2b (battery disconnect transient) by clamping voltages up to 114 V at 3.5 A peak pulse current, well below the 120 V test amplitude and within the 10/1000 µs waveform envelope. Its 400 W peak pulse power rating and fast <1 ps response ensure effective energy diversion before downstream components experience overstress.

Can SMAJ64CH replace SMAJ64AH in an existing design?

No - SMAJ64CH cannot directly replace SMAJ64AH without circuit review. SMAJ64AH is unidirectional and requires correct polarity orientation, whereas SMAJ64CH is bidirectional and lacks defined anode/cathode behavior. Swapping may cause unexpected conduction or failure to clamp if the original layout assumes polarity-dependent placement.

What is the maximum junction temperature rating for SMAJ64CH?

The maximum junction temperature (T_J,max) for SMAJ64CH is +150 °C, with an operating junction temperature range of –55 °C to +150 °C. This rating supports deployment in under-hood automotive locations and industrial environments where ambient temperatures exceed 105 °C, provided PCB thermal relief and power derating per Fig.2 in the datasheet are observed.

SMAJ64CH Specifications

Product attributes: Attribute value

Manufacturer:: Taiwan Semiconductor Corporation

Package/Case:: DO-214AC, SMA

Series:: SMAJ

Packaging:: Tape & Reel (TR)

Product Status:: Active

Type:: Zener

Unidirectional Channels:: -

Bidirectional Channels:: 1

Voltage - Reverse Standoff (Typ):: 64V

Voltage - Breakdown (Min):: 71.1V

Voltage - Clamping (Max) @ Ipp:: 114V

Current - Peak Pulse (10/1000µs):: 3.5A

Power - Peak Pulse:: 400W

Power Line Protection:: No

Applications:: -

Capacitance @ Frequency:: -

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: DO-214AC (SMA)

SMAJ64CH FAQ

1.How can I place an order for SMAJ64CH through Aetrix?

Please submit a Request for Quotation (RFQ) for SMAJ64CH on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for SMAJ64CH reliable?

The price and inventory of SMAJ64CH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ64CH is usually 5 days.

3.What payment methods are accepted for SMAJ64CH?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ64CH transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SMAJ64CH?

SMAJ64CH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SMAJ64CH order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for SMAJ64CH?

For technical support, including SMAJ64CH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ64CH requirements.

6.How does Aetrix verify that SMAJ64CH is sourced from the original manufacturer or authorized distributors?

All SMAJ64CH products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SMAJ64CH meets industry standards.

7.What is the process for return or replacement of SMAJ64CH?

All SMAJ64CH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ64CH, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The SMAJ64CH part is unused and in its original packaging.

Return procedure for SMAJ64CH:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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