My Inquiry
My Account
Diodes Incorporated 1N4746A-T
- Part No.:
- 1N4746A-T
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4746A-T.pdf
- Description:
- DIODE ZENER 18V 1W DO41
- Quantity:
- Payment:
- Shipping:
Inventory:6,612
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
1N4746A-T from Diodes Incorporated is a 1.0 W, 18 V ±5% Zener diode in DO-41 glass package, designed for voltage regulation and reference applications with 20 Ω dynamic impedance at 14 mA test current and -65°C to +175°C operating temperature range. It delivers stable clamping in power supply feedback loops and overvoltage protection circuits.
For engineers reviewing the 1N4746A-T datasheet, 1N4746A-T pinout, 1N4746A-T application, or 1N4746A-T equivalent, key selection criteria include nominal Zener voltage (18 V), power dissipation (1.0 W), Zener impedance (20 Ω @ 14 mA), thermal resistance (175 °C/W), and RoHS-compliant Sn96.5Ag3.5 termination.
Technical Context
This discrete Zener diode operates in reverse breakdown mode to maintain a stable reference voltage across its terminals under varying load and line conditions. Its 18 V nominal Zener voltage is specified at 14 mA test current (IZT), with a sharp knee ensured by dual-point Zener impedance measurement per JEDEC standards.
The device exhibits a positive temperature coefficient (+0.06 to +0.09 %/°C) and supports surge current up to 250 mA (8.3 ms), enabling robust transient suppression in DC power rails. Thermal performance is defined for lead length = 9.5 mm at TL = 50°C, with derating starting above 50°C at 6.67 mW/°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 18 V ±5% at 14 mA - defines precise regulation point for feedback networks |
| Power Dissipation (Pd) | 1.0 W at 25°C - sets maximum continuous steady-state power handling |
| Zener Impedance (ZZT) | 20 Ω @ IZT = 14 mA - determines regulation accuracy under load variation |
| Reverse Leakage (IR) | 5.0 µA @ VR = 13.7 V - ensures low quiescent current in standby states |
| Surge Current (IZS) | 250 mA (8.3 ms) - enables short-duration overvoltage clamping without failure |
| Temp Coefficient (TC) | +0.06 to +0.09 %/°C @ IZT - quantifies voltage drift with ambient temperature change |
| Thermal Resistance (RθJA) | 175 °C/W - defines junction-to-ambient thermal path limitation for PCB layout |
Pinout & Package
DO-41 glass axial package with cathode band marking; two-terminal unidirectional device. No polarity-sensitive mounting orientation beyond cathode identification.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reverse breakdown reference ground | Connected to lower-potential node in shunt regulator configuration |
| Cathode | Zener voltage reference output / Breakdown anode | Connected to regulated rail; cathode band identifies this terminal physically |
Key Features
| Feature | Design Value |
|---|---|
| 1.0 W Power Rating | Enables use in medium-power linear regulators and clamp circuits without heatsinking |
| ±5% Zener Tolerance | Supports cost-sensitive designs where tight initial voltage accuracy is sufficient |
| Sn96.5Ag3.5 Termination | Ensures reliable solderability per MIL-STD-202 Method 208 and RoHS compliance |
| UL 94V-0 Glass Case | Provides flame-retardant mechanical housing suitable for safety-critical PCBs |
| -65°C to +175°C Operating Range | Validates operation in extended industrial and automotive under-hood environments |
Applications
| DC Power Supply Regulation | Overvoltage Protection |
|---|---|
Use Scenario: Shunt regulation in low-current 18 V auxiliary supplies for microcontrollers or sensors. IC Role / Device Role / Timing Role: Voltage reference element providing stable 18 V rail independent of input variation. Use Value: Maintains ±5% output tolerance across 10–100 mA load range with <20 Ω dynamic impedance. | Use Scenario: Clamping transient spikes on 15 V logic bus lines during ESD events. IC Role / Device Role / Timing Role: Fast-acting crowbar element limiting voltage to 18 V before downstream IC damage. Use Value: Absorbs 250 mA surge (8.3 ms) while holding clamped voltage within 10% of nominal. |
| Reference Voltage Source | Signal Level Translation |
Use Scenario: Precision biasing of op-amp input stages requiring stable 18 V reference. IC Role / Device Role / Timing Role: Low-drift voltage source feeding high-impedance analog circuitry. Use Value: Delivers +0.06 to +0.09 %/°C TC for predictable offset compensation over temperature. | Use Scenario: Level-shifting 3.3 V GPIO signals to interface with 18 V industrial control inputs. IC Role / Device Role / Timing Role: Passive pull-up reference defining high-state voltage threshold. Use Value: Provides repeatable 18 V logic-high reference with <5 µA leakage at 13.7 V reverse bias. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DFLZ18-7 | Surface-mount SOD-123FL package; 18 V ±5%; 1.0 W; 25 Ω Zz @ 5 mA | Requires rework of PCB layout for SMT assembly; lower thermal resistance (150 °C/W) | Select for automated production and space-constrained boards where DO-41 axial leads are impractical |
| 1N4746A-A | Identical electrical specs; DO-41 package; ammo pack packaging instead of tape-and-reel | No functional difference; only packaging and reel compatibility differ | Select when manual or semi-automated placement requires bulk ammo-pack format |
Compared with DFLZ18-7 and 1N4746A-A, the 1N4746A-T offers identical Zener performance in tape-and-reel format optimized for pick-and-place machines, while retaining the proven thermal and reliability profile of the DO-41 glass package.
Availability
1N4746A-T is available at Aetrix Electronics and suitable for DC power supply regulation, overvoltage protection, and reference voltage source applications requiring stable component supply and full traceability.
Supply support for 1N4746A-T 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 components for industrial, computing, and consumer markets.
The 1N47xxA series belongs to Diodes' standard Zener diode product line, engineered for general-purpose voltage regulation and clamping in cost-sensitive, high-volume power management circuits.
FAQ
What is the maximum continuous Zener current for 1N4746A-T at 25°C?
The maximum continuous Zener current is calculated as Pd/VZ = 1.0 W / 18 V ≈ 55.6 mA. However, the rated test current (IZT) is 14 mA, and operation above this level increases self-heating and impedance deviation. For stable regulation, design should limit average current to ≤14 mA unless thermal management is verified.
Is 1N4746A-T suitable for automotive under-hood applications?
Yes - its -65°C to +175°C operating temperature range meets extended automotive requirements. The DO-41 glass package has UL 94V-0 flammability rating and Sn96.5Ag3.5 termination qualified for high-temperature soldering. However, it is not AEC-Q200 qualified; for certified automotive use, consult Diodes' AEC-Q200 Zener portfolio.
How does the 1N4746A-T's Zener impedance affect regulation accuracy?
With ZZT = 20 Ω at 14 mA, a 10 mA load change causes ~200 mV output shift (ΔV = ΔI × ZZT). This limits regulation precision in high-dynamic-load applications. For tighter regulation, pair with a series pass transistor or select lower-ZZT devices like 1N4735A (2 Ω) - though at lower voltage ratings.
Why is 1N4746A-T marked "Not Recommended for New Design"?
Diodes Incorporated recommends DFLZxx series for new designs due to superior SMT manufacturability, smaller footprint, and improved thermal resistance. The 1N4746A-T remains fully supported for legacy repair, low-volume production, and prototyping where through-hole DO-41 assembly is preferred or required.
1N4746A-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 20 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 13.7 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-41
1N4746A-T FAQ
1.How can I place an order for 1N4746A-T through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4746A-T 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 1N4746A-T reliable?
The price and inventory of 1N4746A-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4746A-T is usually 5 days.
3.What payment methods are accepted for 1N4746A-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4746A-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4746A-T?
1N4746A-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4746A-T 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 1N4746A-T?
For technical support, including 1N4746A-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4746A-T requirements.
6.How does Aetrix verify that 1N4746A-T is sourced from the original manufacturer or authorized distributors?
All 1N4746A-T 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 1N4746A-T meets industry standards.
7.What is the process for return or replacement of 1N4746A-T?
All 1N4746A-T units undergo pre-shipment inspection (PSI). If there is an issue with 1N4746A-T, 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 1N4746A-T part is unused and in its original packaging.
Return procedure for 1N4746A-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4746A-T 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
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
LDO regulator guide covering low dropout voltage, power dissipation, thermal design, PSRR, output noise, capacitor stability, adjustable LDO circuits, LDO vs buck converter and datasheet selection chec…
Conditional Access Module guide covering CAM meaning, CI/CI+ interface, smart card authorization, DVB security workflow, TV and set-top box compatibility, internal electronics, ESD protection, connecto…
Guide to electronic component obsolescence covering EOL risk, PCN/PDN notices, last-time buy planning, replacement options, form-fit-function validation, counterfeit risk and BOM lifecycle management.
18650 battery guide covering lithium-ion cell basics, 3.6V/3.7V voltage, 4.2V charging, mAh and Wh capacity, protected cells, chargers, BMS, series-parallel packs, holders, welding and sourcing checks.…
Hall effect sensor guide covering working principle, linear and digital sensors, Arduino circuits, current sensing, speed detection, automotive applications, A3144 examples, signal filtering and datash…
Product Change Notification guide for electronic components, covering PCN meaning, PCN vs PDN/EOL, common change types, risk levels, form-fit-function review, engineering validation, BOM control, LTB/L…
A practical guide to blend door actuators, covering HVAC function, symptoms, location, AC and heater issues, reset and calibration, replacement cost, electrical diagnosis, compatibility checks, and rep…
