My Inquiry
My Account
Microchip Technology 1N4746P/TR12
- Part No.:
- 1N4746P/TR12
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4746P/TR12.pdf
- Description:
- DIODE ZENER 18V 1W DO204AL
- Quantity:
- Payment:
- Shipping:
Inventory:4,126
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
1N4746P/TR12 from Microsemi is a 1 W, 18 V ±5% Zener diode in DO-41 plastic package, rated for 14 mA test current, 20 Ω dynamic impedance at IZT, and 0.25 A maximum regulator current at TA = 50°C. It provides stable voltage reference in power supply feedback loops, overvoltage clamping circuits, and precision bias networks.
For engineers reviewing the 1N4746P/TR12 datasheet, 1N4746P/TR12 pinout, 1N4746P/TR12 application, or 1N4746P/TR12 equivalent, key selection criteria include Zener voltage tolerance (±5%), thermal resistance (45°C/W junction-to-lead), surge current rating (250 mA), reverse leakage (<5 µA at 13.7 V), and RoHS-compliant "e3" plating option availability.
Technical Context
This axial-leaded silicon Zener diode operates in reverse breakdown to maintain a stable 18 V reference across a wide current range (0.25 mA to 250 mA). Its 5% voltage tolerance and low dynamic impedance (20 Ω at 14 mA) support consistent regulation under varying load conditions.
The device features a moisture-sensitive Level 1 classification per J-STD-020B, no dry pack required, and is rated for -65°C to +150°C operation. Thermal resistance is specified as 45°C/W junction-to-lead (3/8" lead length) and 105°C/W junction-to-ambient on FR4 with defined copper pad geometry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 18 V ±5% at IZT = 14 mA - defines nominal regulation point with tight production control |
| Power Dissipation | 1.0 W at TL < 105°C - limits continuous thermal stress with standard lead mounting |
| Dynamic Impedance | 20 Ω at IZT = 14 mA - ensures minimal output voltage variation under load transients |
| Reverse Leakage Current | <5 µA at VR = 13.7 V - guarantees low standby power loss in high-impedance bias networks |
| Surge Current (ISM) | 250 mA (½-sine, 1/120 s) - supports transient overvoltage suppression without failure |
| Thermal Resistance | 45°C/W junction-to-lead - enables accurate thermal design using standard lead-length derating curves |
| Operating Temperature | -65°C to +150°C - suitable for industrial and automotive under-hood environments |
Pinout & Package
DO-41 (DO-204AL) plastic axial-leaded package with cathode indicated by color band. Leads are tin-lead or RoHS-compliant matte-tin plated, solderable per MIL-STD-750 Method 2026.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Non-banded end | Connected to lower-potential node; forward voltage ≤1.2 V @ 200 mA |
| Cathode | Banded end | Connected to higher-potential node during Zener operation; defines regulation polarity |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered 1N47xxAP series | Industry-standard footprint and electrical behavior enabling direct BOM substitution |
| Plastic encapsulation (P suffix) | Lower thermal resistance vs. glass-body (G suffix) variants - improves power handling reliability |
| Moisture sensitivity Level 1 | No dry pack required before PCB assembly - reduces manufacturing overhead and shelf-life risk |
| RoHS-compliant "e3" option | Matte-tin plating meets EU Directive 2011/65/EU without lead content compromise on solderability |
| Nonsensitive to ESD | Qualified per MIL-STD-750 Method 1020 - eliminates need for special handling in standard assembly lines |
Applications
| Power Supply Feedback | Voltage Clamp Protection |
|---|---|
Use Scenario: Regulating output voltage in discrete linear regulators or TL431-based shunt references. IC Role / Device Role / Timing Role: Provides precise 18 V reference for error amplifier feedback network. Use Value: Maintains ±5% output accuracy across line/load/temperature with 20 Ω dynamic impedance limiting ripple coupling. | Use Scenario: Suppressing voltage spikes on 12–24 V DC rails in automotive ECUs and industrial PLCs. IC Role / Device Role / Timing Role: Acts as bidirectional transient clamp when paired with series resistor. Use Value: Absorbs 250 mA surge pulses without degradation, leveraging 1 W steady-state rating for sustained overvoltage events. |
| Bias Network Reference | Signal-Level Shaping |
Use Scenario: Setting operating points for op-amp input stages or transistor amplifiers in sensor interfaces. IC Role / Device Role / Timing Role: Delivers stable 18 V bias to high-impedance nodes with sub-µA leakage. Use Value: Enables predictable DC gain and offset control via <5 µA reverse leakage at 13.7 V test voltage. | Use Scenario: Limiting analog signal swing in audio preamps or data acquisition front-ends. IC Role / Device Role / Timing Role: Clamps positive excursions to 18.9 V (18 V + 5%) while passing negative half-cycles. Use Value: Prevents ADC saturation or op-amp rail-to-rail overload using sharp knee impedance (ZZK = 0.5 Ω @ IZK = 0.25 mA). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4746A | No "P" suffix - glass-body DO-35 package; higher thermal resistance (65°C/W junction-to-lead) | Less suitable for high-reliability, high-power-density layouts requiring plastic's lower RθJL | Select 1N4746P/TR12 when thermal performance or moisture robustness is critical |
| MMSZ4708T1G | Surface-mount SOD-123; 18 V ±5%, 500 mW rating; ZZT = 40 Ω @ 5 mA | Not interchangeable without PCB redesign; lower power and higher impedance limit use in 1 W analog references | Choose MMSZ4708T1G only for space-constrained, low-power SMT designs where 1N4746P/TR12's axial form is impractical |
Compared with 1N4746A and MMSZ4708T1G, the 1N4746P/TR12 offers superior thermal management (45°C/W vs. 65°C/W), guaranteed plastic-body reliability (Level 1 moisture), and full 1 W dissipation capability - making it optimal for through-hole industrial power regulation where long-term stability and surge resilience are prioritized.
Availability
1N4746P/TR12 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and test equipment requiring stable component supply with traceable sourcing and lifecycle continuity.
Supply support for 1N4746P/TR12 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
Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog and mixed-signal components for aerospace, defense, and industrial markets.
The 1N47xxAP series was designed specifically for ruggedized voltage regulation in mission-critical power systems where thermal stability, ESD immunity, and long-term parametric consistency are mandatory.
FAQ
What is the Zener voltage tolerance of the 1N4746P/TR12?
The 1N4746P/TR12 has a nominal Zener voltage of 18 V with a tolerance of ±5%, as confirmed by its "A" suffix per JEDEC registration. This tolerance applies at TL = 25°C and IZT = 14 mA. Tighter tolerances (e.g., ±2% or ±1%) require C or D suffixes, which are not present in the 1N4746P/TR12 designation.
Does the 1N4746P/TR12 have RoHS-compliant plating?
Yes - the "e3" suffix in the full Microsemi part number (1N4746AP,e3) indicates RoHS-compliant matte-tin plating. While the orderable part 1N4746P/TR12 omits "e3" in its marking, Microsemi's documentation confirms all 1N47xxAP,e3 devices shipped post-2005 meet RoHS Directive 2011/65/EU, and the TR12 tape-and-reel packaging is compatible with this specification.
What is the maximum steady-state current the 1N4746P/TR12 can regulate continuously?
The 1N4746P/TR12 supports a maximum regulator current (IZM) of 0.25 A at ambient temperature TA = 50°C when mounted on an FR4 board with specified copper layout. At lower temperatures or with enhanced heatsinking, current capacity increases per the derating curve in Figure 1 of the datasheet - but 0.25 A remains the validated safe operating limit under standard conditions.
Can the 1N4746P/TR12 be used in place of the 1N4746A?
Yes, the 1N4746P/TR12 is functionally identical to the 1N4746A in electrical specifications (18 V ±5%, 1 W, same IZT and ZZT values), but uses a plastic DO-41 package instead of glass DO-35. The "P" variant offers lower thermal resistance (45°C/W vs. 65°C/W) and Level 1 moisture sensitivity - making it preferable for high-reliability or humid-environment applications where the 1N4746A may require dry-pack handling.
What does the "TR12" suffix indicate in 1N4746P/TR12?
The "TR12" suffix denotes tape-and-reel packaging per EIA-296 standard, with 12 mm tape width and component spacing optimized for automated pick-and-place assembly. This format supports high-volume manufacturing and ensures consistent orientation (cathode band aligned) during placement - critical for maintaining correct polarity in automated soldering processes involving the 1N4746P/TR12.
1N4746P/TR12 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±10%
- 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 ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AL (DO-41)
1N4746P/TR12 FAQ
1.How can I place an order for 1N4746P/TR12 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4746P/TR12 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 1N4746P/TR12 reliable?
The price and inventory of 1N4746P/TR12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4746P/TR12 is usually 5 days.
3.What payment methods are accepted for 1N4746P/TR12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4746P/TR12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4746P/TR12?
1N4746P/TR12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4746P/TR12 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 1N4746P/TR12?
For technical support, including 1N4746P/TR12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4746P/TR12 requirements.
6.How does Aetrix verify that 1N4746P/TR12 is sourced from the original manufacturer or authorized distributors?
All 1N4746P/TR12 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 1N4746P/TR12 meets industry standards.
7.What is the process for return or replacement of 1N4746P/TR12?
All 1N4746P/TR12 units undergo pre-shipment inspection (PSI). If there is an issue with 1N4746P/TR12, 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 1N4746P/TR12 part is unused and in its original packaging.
Return procedure for 1N4746P/TR12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4746P/TR12 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
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…
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…
