My Inquiry
My Account
Taiwan Semiconductor Corporation SMAJ85CH
- Part No.:
- SMAJ85CH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ85CH.pdf
- Description:
- TVS DIODE 85VWM 151VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,424
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMAJ85CH from Taiwan Semiconductor is a bidirectional surface-mount transient voltage suppressor (TVS) diode designed for automotive-grade overvoltage protection in DC power rails and signal lines. It features a 85 V working stand-off voltage (VWM), 94.4–115 V breakdown voltage (VBR), 151 V maximum clamping voltage (VC) at 2.0 A peak impulse current, and 400 W peak pulse power rating per 10/1000 µs waveform - meeting ISO 7637-2 Pulse 1/2a/2b/3a/3b for vehicle electronics.
For engineers reviewing the SMAJ85CH datasheet, SMAJ85CH pinout, SMAJ85CH application, or SMAJ85CH equivalent, key selection criteria include its AEC-Q101 qualification, DO-214AC (SMA) package compatibility with automated placement, bidirectional clamping symmetry, moisture sensitivity level 1 (J-STD-020), and compliance with ISO 7637-2 for harsh automotive transients.
Technical Context
The SMAJ85CH implements a glass-passivated silicon junction optimized for fast transient response (<1.0 ps from 0 V to VBR min) and low leakage (<1 µA at VWM). Its bidirectional configuration enables symmetrical clamping in both polarities without external polarity management, supporting robust protection of CAN, LIN, and sensor interfaces against load dump and inductive switching events.
Thermal design is enabled by a 150 °C maximum junction temperature and 1 W steady-state power dissipation, while mechanical robustness is ensured via UL 94V-0 molding compound, matte tin-plated leads (J-STD-002 compliant), and JESD 201 Class 2 whisker resistance - all validated under AEC-Q101 stress testing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 85 V - Maximum continuous reverse operating voltage before clamping initiates |
| VBR min/max | 94.4 V / 115 V at 1 mA test current - Ensures reliable turn-on margin above system nominal voltage |
| VC @ IPPM | 151 V at 2.0 A - Clamping voltage during 10/1000 µs surge defines worst-case protected node voltage |
| PPPM | 400 W - Peak pulse power handling capability per standard 10/1000 µs waveform |
| IR @ VWM | <1 µA - Negligible leakage current preserves battery drain budget in always-on circuits |
| TJ max | 150 °C - Enables operation in under-hood automotive environments without derating |
| Package | DO-214AC (SMA) - Industry-standard SMD footprint compatible with high-volume pick-and-place |
Pinout & Package
DO-214AC (SMA) package: surface-mount, single-diode bidirectional configuration with cathode band omitted (symmetrical terminals). Matte tin-plated leads, 0.060 g weight, UL 94V-0 flammability rating, polarity not marked - terminals are functionally identical.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (bidirectional) | Transient current path | Either terminal accepts surge current in either polarity; no directional installation required |
| Case | Thermal conduction path | Exposed metal-free plastic body; heat dissipation relies on PCB copper area and trace width |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive use including temperature cycling, humidity bias, and mechanical shock per JESD47 |
| ISO 7637-2 compliance | Passes Pulse 1 (inductive load disconnect), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) tests |
| Fast response time | <1.0 ps from 0 V to VBR min - Limits voltage overshoot before clamping engages |
| Moisture sensitivity level 1 | No floor life limitation; safe for reflow without baking per J-STD-020 |
| Halogen-free construction | Complies with IEC 61249-2-21 - Supports RoHS and environmental compliance programs |
Applications
| Automotive Body Control Module (BCM) | On-board DC/DC Converter Input Protection |
|---|---|
Use Scenario: Protects microcontroller I/O and LIN bus transceivers from battery line transients during load dump or jump-start events. IC Role / Device Role / Timing Role: Bidirectional TVS clamps ±100 V surges to ≤151 V, preserving signal integrity and preventing latch-up in 5 V/3.3 V logic domains. Use Value: Eliminates need for external polarity selection or dual unidirectional devices - reduces BOM count and layout area by 50%. | Use Scenario: Shields primary-side MOSFET gate drivers and feedback resistors from 12 V/24 V rail spikes induced by relay switching or alternator regulation. IC Role / Device Role / Timing Role: Absorbs 400 W transient energy within 1 ms, limiting input voltage excursion to protect downstream PWM controllers and optocouplers. Use Value: Enables direct integration into compact DC/DC modules without heatsinking - supports >100 khr MTBF in automotive thermal profiles. |
| LED Headlamp Driver Protection | Industrial CAN Bus Node Interface |
Use Scenario: Guards constant-current LED driver ICs against inductive kickback from headlamp relay coils and ESD from service port connections. IC Role / Device Role / Timing Role: Clamps bidirectional transients up to ±151 V while maintaining <1 µA leakage at 85 V - avoids false triggering of overvoltage shutdown. Use Value: Maintains stable LED output across full vehicle lifecycle without calibration drift due to leakage-induced bias shift. | Use Scenario: Protects CAN transceiver PHY layer from ESD (IEC 61000-4-2) and burst noise (IEC 61000-4-4) in factory automation nodes. IC Role / Device Role / Timing Role: Provides sub-nanosecond response to fast-rising transients, ensuring CAN bit timing integrity remains unaffected during clamping. Use Value: Guarantees >10⁴ insertion loss cycles without parameter degradation - validated per AEC-Q101 HTRB and TC testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ85AHE3/5BT | Unidirectional variant with 10.3 V lower clamping voltage (137 V vs. 151 V) and tighter VBR tolerance (94.4–104 V) | Requires correct polarity orientation; unsuitable for AC-coupled or floating-bus systems | Select when protecting unidirectional rails with strict VC budget and polarity is fixed |
| SMCJ85CA | Higher power rating (1500 W), larger DO-214AB (SMB) package, 152 V clamping voltage | Occupies 2.5× PCB area; suited for higher-energy transients but incompatible with SMA footprints | Choose for industrial power supplies where surge energy exceeds 400 W and board space allows SMB |
Compared with SMAJ85CH, SMAJ85AHE3/5BT offers lower clamping but requires polarity-aware layout, while SMCJ85CA delivers greater surge capacity at the cost of footprint compatibility - SMAJ85CH uniquely balances AEC-Q101 compliance, bidirectional symmetry, and DO-214AC scalability for automotive electronics.
Availability
SMAJ85CH is available at Aetrix Electronics and suitable for automotive body control modules, on-board DC/DC converters, LED lighting drivers, and industrial CAN bus nodes requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SMAJ85CH 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, MOSFETs, and automotive-qualified components.
The SMAJ series was developed specifically for AEC-Q101-compliant transient suppression in 12 V/24 V automotive subsystems, emphasizing reliability under ISO 7637-2 stress conditions and compatibility with high-speed automated assembly.
FAQ
What does the 'CH' suffix indicate in SMAJ85CH?
The 'CH' suffix in SMAJ85CH denotes a bidirectional configuration with a center-tapped or symmetrical junction structure - enabling identical clamping behavior for positive and negative transients without polarity marking. This distinguishes it from unidirectional variants like SMAJ85AH and ensures compatibility with floating or AC-coupled signal paths in automotive networks.
Is SMAJ85CH suitable for protecting a 24 V CAN FD interface?
Yes, SMAJ85CH is suitable for protecting a 24 V CAN FD interface: its 85 V working stand-off voltage provides ample margin above the 30 V common-mode range of CAN FD transceivers, and its 151 V clamping voltage ensures bus signals remain within ISO 11898-2 fault tolerance limits. The bidirectional nature also maintains signal symmetry during differential transient events.
Does SMAJ85CH require a heatsink in typical automotive applications?
No, SMAJ85CH does not require an external heatsink in typical automotive applications. Its 1 W steady-state power dissipation and 150 °C maximum junction temperature are designed for conduction cooling through standard PCB copper pours. Thermal performance is validated under AEC-Q101 conditions with no forced airflow - heatsinking is only needed for repetitive surges exceeding 1 Hz.
How does SMAJ85CH meet ISO 7637-2 Pulse 1 requirements?
SMAJ85CH meets ISO 7637-2 Pulse 1 (inductive load disconnect) by clamping the −150 V/0.5 Ω transient to ≤151 V at 2.0 A, limiting energy dissipation to 400 W within the 10/1000 µs waveform envelope. Its sub-nanosecond response time prevents voltage overshoot beyond specification limits, and its AEC-Q101 qualification confirms robustness across 1000+ pulse cycles.
Can SMAJ85CH be used in place of SMAJ85AH in an existing design?
No, SMAJ85CH cannot be directly substituted for SMAJ85AH without layout review: SMAJ85AH is unidirectional and requires correct cathode orientation, while SMAJ85CH is bidirectional with no polarity marking. Swapping them may cause improper clamping in DC-biased circuits. If bidirectional protection is needed, verify that the circuit topology supports symmetrical voltage limiting on both rails.
SMAJ85CH 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):
- 85V
- Voltage - Breakdown (Min):
- 94.4V
- Voltage - Clamping (Max) @ Ipp:
- 151V
- Current - Peak Pulse (10/1000µs):
- 2A
- 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)
SMAJ85CH FAQ
1.How can I place an order for SMAJ85CH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ85CH 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 SMAJ85CH reliable?
The price and inventory of SMAJ85CH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ85CH is usually 5 days.
3.What payment methods are accepted for SMAJ85CH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ85CH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ85CH?
SMAJ85CH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ85CH 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 SMAJ85CH?
For technical support, including SMAJ85CH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ85CH requirements.
6.How does Aetrix verify that SMAJ85CH is sourced from the original manufacturer or authorized distributors?
All SMAJ85CH 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 SMAJ85CH meets industry standards.
7.What is the process for return or replacement of SMAJ85CH?
All SMAJ85CH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ85CH, 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 SMAJ85CH part is unused and in its original packaging.
Return procedure for SMAJ85CH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ85CH Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
