My Inquiry
My Account
Microchip Technology 1N4745UR/TR
- Part No.:
- 1N4745UR/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-213AB, MELF (Glass)
- Datasheet:
-
1N4745UR/TR.pdf
- Description:
- DIODE ZENER 16V 1W DO213AB
- Quantity:
- Payment:
- Shipping:
Inventory:6,140
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
1N4745UR/TR from Microsemi is a surface-mount 1.0 W glass-encapsulated Zener diode with nominal Zener voltage 16 V, ±5% tolerance (A-suffix), 15.5 mA test current (IZT), 16 Ω dynamic impedance (ZZT), and 0.25 A maximum regulator current (IZM) at TA = 50°C. It operates from –65°C to +175°C and is used for precision voltage regulation in high-density power supply rails and reference circuits.
For engineers reviewing the 1N4745UR/TR datasheet, 1N4745UR/TR pinout, 1N4745UR/TR application, or 1N4745UR/TR equivalent, key selection criteria include its DO-213AB MELF glass package, hermetic sealing, low parasitic capacitance, radiation hardness per MicroNote 050, and compatibility with automated SMT assembly under JEDEC-standard reflow profiles.
Technical Context
This Zener diode delivers stable voltage regulation across wide temperature (–65°C to +175°C) and current ranges, with thermal resistance of 50°C/W junction-to-end-cap and 130°C/W junction-to-ambient on FR4. Its glass MELF construction ensures low leakage (<5 µA at VR = 12.2 V) and inherent ESD insensitivity.
The device exhibits a sharp breakdown knee (ZZK = 57 Ω at IZK = 0.25 mA), supports surge current up to 285 mA (½-sine, 1/120 s), and maintains regulation with forward voltage ≤1.2 V at 200 mA - enabling bidirectional protection and reference stability in compact DC-DC feedback paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 16 V ±5% - precise regulation point for 15–17 V rail stabilization |
| Power Dissipation | 1.0 W at TC ≤ 125°C - supports continuous operation in thermally constrained layouts |
| Test Current (IZT) | 15.5 mA - defines operating point where VZ and ZZT are specified |
| Dynamic Impedance (ZZT) | 16 Ω @ IZT - low AC impedance ensures minimal output voltage variation under load transients |
| Max Regulator Current (IZM) | 0.25 A at TA = 50°C - sets safe DC current limit for sustained regulation |
| Reverse Leakage (IR) | ≤5 µA @ VR = 12.2 V - guarantees low quiescent loss in standby mode |
| Operating Temperature | –65°C to +175°C - qualified for aerospace, downhole, and industrial environments |
Pinout & Package
Package: DO-213AB glass MELF - hermetically sealed, leadless, cylindrical surface-mount package with cathode band marking; compatible with EIA-481-B tape-and-reel (12 mm tape, 1500/reel with TR suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Non-banded end | Connected to lower-potential node; forward conduction path when biased >1.2 V |
| Cathode | Banded end | Connected to regulated voltage node; Zener breakdown occurs with cathode positive relative to anode |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic Glass MELF Construction | Enables operation up to +175°C and eliminates moisture-induced parameter drift |
| Radiation Hardness | Inherently radiation-hard per MicroNote 050 - suitable for space-grade and nuclear instrumentation |
| Low Dynamic Impedance | 16 Ω at 15.5 mA - minimizes output ripple in analog references and feedback loops |
| ESD Insensitivity | No special handling required - robust against human-body-model discharges during assembly |
| RoHS Compliance | e3 suffix indicates lead-free matte-tin plating - meets IPC-J-STD-020 reflow standards |
Applications
| Power Supply Reference | Overvoltage Clamp |
|---|---|
Use Scenario: Stabilizing feedback node in isolated DC-DC converters with <5% output tolerance requirement. IC Role / Device Role / Timing Role: Voltage reference element defining output setpoint via optocoupler or error amplifier input. Use Value: 16 V Zener voltage and 16 Ω impedance maintain <±0.1 V regulation shift across 5–20 mA load range. |
Use Scenario: Protecting microcontroller I/O pins from transient overvoltage events exceeding 12 V. IC Role / Device Role / Timing Role: Shunt clamping device diverting surge current away from sensitive inputs. Use Value: 285 mA surge rating and 12.2 V test voltage ensure reliable clamping without thermal runaway. |
| High-Temperature Sensor Bias | Aerospace Voltage Monitor |
Use Scenario: Providing stable bias current to RTD or thermistor signal conditioning circuits in engine control units. IC Role / Device Role / Timing Role: Precision current source via series resistor + Zener voltage drop. Use Value: –65°C to +175°C operating range and low tempco support ±0.5% bias accuracy over full range. |
Use Scenario: Monitoring bus voltage integrity in satellite power distribution units requiring radiation-tolerant components. IC Role / Device Role / Timing Role: Standby reference for comparator-based undervoltage/overvoltage detection. Use Value: Hermetic seal and radiation hardness prevent parametric degradation in LEO radiation environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4745A | Same electrical specs but DO-41 axial-leaded package; no MELF geometry or surface-mount footprint | Requires through-hole PCB layout and manual/automated insertion; unsuitable for high-density SMT designs | Select 1N4745A only when legacy through-hole assembly or board repair is required |
| SMAJ4745A | Same Zener voltage and tolerance, but plastic SMA package; higher thermal resistance (150°C/W) and lower surge rating (200 mA) | Limited to commercial-temperature applications; not rated for >150°C ambient or radiation exposure | Choose SMAJ4745A for cost-sensitive consumer designs where hermeticity and extended temperature are not critical |
Compared with 1N4745A and SMAJ4745A, the 1N4745UR/TR uniquely combines surface-mount compatibility, hermetic glass reliability, radiation hardness, and extended temperature operation - making it the sole option for high-reliability SMT voltage regulation where environmental robustness is mandatory.
Availability
1N4745UR/TR is available at Aetrix Electronics and suitable for high-temperature power supplies, aerospace voltage monitors, and industrial sensor bias circuits requiring stable component supply with traceable sourcing and long-term lifecycle support.
Supply support for 1N4745UR/TR 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, radiation-hardened, and high-temperature analog and mixed-signal components.
The 1N4745UR/TR belongs to Microsemi's surface-mount Zener diode family designed for mission-critical voltage regulation in aerospace, defense, oil & gas, and industrial control systems where hermeticity and extended temperature performance are essential.
FAQ
What is the Zener voltage tolerance for 1N4745UR/TR?
The 1N4745UR/TR has a nominal Zener voltage of 16 V with ±5% tolerance, indicated by the "A" suffix in its designation. This means the actual measured VZ at 15.5 mA test current falls between 15.2 V and 16.8 V under standard test conditions (TC = 30°C, 90-second stabilization).
Does 1N4745UR/TR require special handling for ESD sensitivity?
No - the 1N4745UR/TR is nonsensitive to ESD per its datasheet, due to its glass MELF construction and intrinsic junction characteristics. Standard SMT handling procedures apply; no ionized air or grounded workstations are mandated for this device.
Can 1N4745UR/TR be used in reflow soldering processes?
Yes - the 1N4745UR/TR supports standard lead-free reflow profiles, including peak temperatures up to 260°C for 10 seconds. Its DO-213AB package and annealed matte-tin plating comply with MIL-STD-750 Method 2026 for solderability.
What is the maximum steady-state power dissipation for 1N4745UR/TR?
The 1N4745UR/TR is rated for 1.00 W steady-state power dissipation at end-cap temperature (TEC) < 125°C or ambient temperature (TA) < 45°C when mounted on FR4 with recommended pad layout. Derating is required above those temperatures per Figure 1 in the datasheet.
Is 1N4745UR/TR radiation-hardened?
Yes - the 1N4745UR/TR is inherently radiation-hard per MicroNote 050, a documented characteristic of its glass-encapsulated MELF structure. It is qualified for use in low-earth-orbit (LEO) and other radiation-exposed environments without additional screening.
1N4745UR/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-213AB, MELF (Glass)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 16 V
- Tolerance:
- ±10%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 16 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 12.2 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-213AB (MELF, LL41)
1N4745UR/TR FAQ
1.How can I place an order for 1N4745UR/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4745UR/TR 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 1N4745UR/TR reliable?
The price and inventory of 1N4745UR/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4745UR/TR is usually 5 days.
3.What payment methods are accepted for 1N4745UR/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4745UR/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4745UR/TR?
1N4745UR/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4745UR/TR 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 1N4745UR/TR?
For technical support, including 1N4745UR/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4745UR/TR requirements.
6.How does Aetrix verify that 1N4745UR/TR is sourced from the original manufacturer or authorized distributors?
All 1N4745UR/TR 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 1N4745UR/TR meets industry standards.
7.What is the process for return or replacement of 1N4745UR/TR?
All 1N4745UR/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4745UR/TR, 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 1N4745UR/TR part is unused and in its original packaging.
Return procedure for 1N4745UR/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4745UR/TR 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…
