My Inquiry
My Account
onsemi 1SMA5943BT3
- Part No.:
- 1SMA5943BT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA5943BT3.pdf
- Description:
- DIODE ZENER 56V 1.5W SMA
- Quantity:
- Payment:
- Shipping:
Inventory:8,225
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
1SMA5943BT3 from onsemi is a 1.5 W surface-mount Zener diode with nominal zener voltage of 56 V (±5%), maximum zener impedance of 6.7 Ω at 86 mA test current, and reverse leakage current ≤0.25 μA at 42.6 V. It features AEC-Q101 qualification, ESD rating >16 kV (HBM), and UL 94 V-0 flammability compliance. Used for precision voltage regulation and overvoltage protection in automotive power supplies and industrial DC rails.
For engineers reviewing the 1SMA5943BT3 datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, dynamic impedance at rated test current, thermal resistance (RJA = 250 °C/W), junction temperature range (−65 to +150 °C), and Pb-free SMA package compatibility with automated SMT assembly.
Technical Context
This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown when biased above its specified VZ threshold. Its regulation performance is defined at IZT = 86 mA, where VZ = 53.2–58.8 V and ZZT ≤ 6.7 Ω, with low dynamic impedance ensuring stable clamping under transient load changes.
Thermal design relies on FR-4 board mounting with minimum recommended footprint; power derating begins at TA = 25 °C (0.5 W) and TL = 75 °C (1.5 W), with RJL = 50 °C/W and RJA = 250 °C/W. Polarity is marked by cathode band, and case temperature during soldering must not exceed 260 °C for 10 seconds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 53.2–58.8 V @ IZT = 86 mA - defines regulated output voltage window under nominal bias |
| Zener Impedance (ZZT) | ≤6.7 Ω @ IZT = 86 mA - ensures minimal voltage deviation during current transients |
| Max DC Power Dissipation | 0.5 W @ TA = 25 °C - sets absolute thermal limit for ambient-mounted operation |
| Reverse Leakage Current | ≤0.25 μA @ VR = 42.6 V - guarantees low standby power loss in high-impedance bias networks |
| Junction Temperature Range | −65 to +150 °C - supports operation in under-hood automotive and industrial environments |
| ESD Rating (HBM) | >16 kV - enables robust handling without external protection in assembly and field service |
| Package | SMA (DO-214AC, Case 403D-02) - standard SMT outline with 4.06–4.57 mm body width and 2.29–2.92 mm height |
Pinout & Package
SMA package (Case 403D-02) is a surface-mount, low-profile plastic case with flat handling surface and molded cathode polarity band. Dimensions: D = 2.29–2.92 mm, E = 4.06–4.57 mm, L = 0.76–1.52 mm. Cathode terminal is marked by band; anode is unmarked end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Reverse-biased input | Connected to higher-potential rail; breakdown occurs when voltage exceeds VZ |
| Anode (unmarked end) | Reference/return node | Typically tied to system ground or low-side bias point; completes conduction path during regulation |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive powertrain and body electronics per stress test requirements |
| Pb-free (G-suffix compatible) | Meets RoHS Directive 2011/65/EU; compatible with lead-free reflow profiles |
| UL 94 V-0 flammability rating | Self-extinguishing plastic housing prevents fire propagation in fault conditions |
| Flat handling surface | Enables accurate pick-and-place placement and consistent solder joint formation |
| Top-slide or bottom-mount capability | Flexible board layout integration without orientation constraints |
Applications
| Automotive Engine Control Unit (ECU) Power Rail Clamp | Industrial PLC Analog Input Protection |
|---|---|
Use Scenario: Clamps 12 V/24 V battery-supplied microcontroller power rails against load-dump transients up to 60 V. IC Role / Device Role / Timing Role: Zener diode acting as shunt regulator and overvoltage clamp in parallel with LDO input. Use Value: Maintains regulated 56 V breakdown threshold to protect downstream regulators while dissipating <0.5 W under steady-state conditions. | Use Scenario: Protects 0–10 V analog input channels from ESD and wiring-induced surges in factory automation systems. IC Role / Device Role / Timing Role: Standby leakage-limited voltage clamp placed before op-amp input stage. Use Value: Limits input voltage to ≤58.8 V with ≤0.25 μA leakage at 42.6 V, preserving signal integrity and ADC accuracy. |
| Telecom DC-DC Converter Feedback Reference | Medical Equipment Power Supply Monitor |
Use Scenario: Provides stable voltage reference for optocoupler feedback loop in isolated 48 V telecom DC-DC converters. IC Role / Device Role / Timing Role: Precision Zener used as secondary-side voltage sense element in closed-loop regulation. Use Value: Delivers ±5% VZ tolerance and 6.7 Ω dynamic impedance to minimize feedback error across temperature and line variations. | Use Scenario: Monitors auxiliary 24 V supply rail in diagnostic imaging equipment to trigger shutdown if voltage exceeds safe limits. IC Role / Device Role / Timing Role: Overvoltage detection element interfaced with comparator input. Use Value: Enables reliable trip point at 56 V with predictable thermal drift (θVZ ~+0.085 %/°C per curve Fig.6), supporting IEC 60601-1 compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C56LT1G | 0.3 W rating, SOT-23 package, VZ = 52–60 V (±5%), ZZT = 100 Ω @ 5 mA | Lower power handling; suited for signal-level biasing, not power rail clamping | Select when board space is constrained and dissipation remains <300 mW |
| 1N5365B | 5 W axial-leaded DO-15 package, VZ = 56 V (±5%), ZZT = 1.5 Ω @ 175 mA | Higher power capacity but through-hole mounting; no AEC-Q101 or Pb-free assurance | Select for legacy designs requiring higher surge energy absorption without SMT conversion |
Compared with BZX84-C56LT1G and 1N5365B, the 1SMA5943BT3 delivers optimal balance of SMT compatibility, automotive qualification, and 1.5 W regulation capability-making it preferred for new automotive and industrial PCB designs where reliability, thermal management, and regulatory compliance are critical.
Availability
1SMA5943BT3 is available at Aetrix Electronics and suitable for automotive engine control units, industrial programmable logic controllers, telecom DC-DC converters, and medical power supply monitors requiring stable component supply with full traceability and lifecycle support.
Supply support for 1SMA5943BT3 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, and consumer markets.
The 1SMA59xxBT3 series was designed specifically for high-reliability surface-mount voltage regulation in automotive and industrial applications-emphasizing AEC-Q101 compliance, robust ESD immunity, and thermally stable Zener performance in compact SMA packaging.
FAQ
What is the exact zener voltage tolerance for 1SMA5943BT3?
The 1SMA5943BT3 has a nominal zener voltage of 56 V with a tolerance of ±5%, meaning the actual measured VZ falls between 53.2 V and 58.8 V when tested at IZT = 86 mA and TA = 25 °C. This tolerance is guaranteed per the device marking code "843B" and confirmed in the Electrical Characteristics table on page 2 of the official datasheet.
Is 1SMA5943BT3 suitable for automotive applications?
Yes, the 1SMA5943BT3 is AEC-Q101 qualified and PPAP capable when ordered as SZ1SMA5943BT3G. The "SZ" prefix denotes automotive-grade screening, including stress testing for temperature cycling, humidity, and mechanical shock. This makes 1SMA5943BT3 appropriate for under-hood and chassis-mounted modules where reliability under harsh environmental conditions is required.
What is the maximum allowable soldering temperature for 1SMA5943BT3?
The maximum case temperature for soldering the 1SMA5943BT3 is 260 °C for up to 10 seconds, as specified in the Mechanical Characteristics section. This applies to both wave and reflow processes. Exceeding this limit risks internal delamination or bond wire damage. The device uses void-free transfer-molded plastic (UL 94 V-0) and corrosion-resistant, readily solderable leads.
Does 1SMA5943BT3 have Pb-free packaging options?
Yes, the "G" suffix in SZ1SMA5943BT3G explicitly indicates a Pb-free package compliant with RoHS Directive 2011/65/EU. The base part number 1SMA5943BT3 may be supplied in either standard or Pb-free form depending on order code; however, all current production shipments from onsemi are Pb-free, and the G-suffix variant is fully drop-in compatible with identical electrical and thermal specifications.
How does the thermal resistance of 1SMA5943BT3 affect its power handling?
The 1SMA5943BT3 has RJA = 250 °C/W and RJL = 50 °C/W. At TA = 25 °C, its max power is 0.5 W; at TL = 75 °C, it rises to 1.5 W. This means effective power handling depends critically on PCB copper area and thermal vias. For example, using a 1 in² copper pad (per Note 1) allows full 1.5 W operation only if the lead temperature stays at 75 °C-requiring careful thermal layout to avoid exceeding TJ = +150 °C.
1SMA5943BT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 1SMA59xxBT3G
- Package/Case:
- DO-214AC, SMA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 56 V
- Tolerance:
- ±5%
- Power - Max:
- 1.5 W
- Impedance (Max) (Zzt):
- 86 Ohms
- Current - Reverse Leakage @ Vr:
- 500 nA @ 42.6 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA5943BT3 FAQ
1.How can I place an order for 1SMA5943BT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA5943BT3 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 1SMA5943BT3 reliable?
The price and inventory of 1SMA5943BT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA5943BT3 is usually 5 days.
3.What payment methods are accepted for 1SMA5943BT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA5943BT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA5943BT3?
1SMA5943BT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA5943BT3 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 1SMA5943BT3?
For technical support, including 1SMA5943BT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA5943BT3 requirements.
6.How does Aetrix verify that 1SMA5943BT3 is sourced from the original manufacturer or authorized distributors?
All 1SMA5943BT3 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 1SMA5943BT3 meets industry standards.
7.What is the process for return or replacement of 1SMA5943BT3?
All 1SMA5943BT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA5943BT3, 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 1SMA5943BT3 part is unused and in its original packaging.
Return procedure for 1SMA5943BT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA5943BT3 Tags
-
MMBZ5240B-7-F
Diodes Incorporated
-
BZT52C5V6T-7
Diodes Incorporated
-
MMSZ5231B-7-F
Diodes Incorporated
-
BZT52C15-7-F
Diodes Incorporated
-
BZX84C3V3LT1G
onsemi
-
MMSZ5245BS-7-F
Diodes Incorporated
-
MMSZ4682T1G
onsemi
-
BZT52C15S-7-F
Diodes Incorporated
-
MM5Z5V1ST1G
onsemi
-
SMAJ4744A-TP
Micro Commercial Co
-
BZT52C3V6LP-7
Diodes Incorporated
-
SMAZ12-13-F
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…
