My Inquiry
My Account
Diodes Incorporated 1N5251B-T
- Part No.:
- 1N5251B-T
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N5251B-T.pdf
- Description:
- DIODE ZENER 22V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:3,352
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
1N5251B-T from Diodes Incorporated is a 22V ±5% tolerance, 500mW surface-mount Zener diode in a hermetic DO-35 glass package, rated for operation from −65°C to +175°C, with 5.6mA test current, 29Ω dynamic impedance at IZT, and +0.087%/°C temperature coefficient - used for precision voltage reference and overvoltage protection in power supply feedback loops.
For engineers reviewing the 1N5251B-T datasheet, 1N5251B-T pinout, 1N5251B-T application, or 1N5251B-T equivalent, key selection considerations include Zener voltage stability under thermal drift, low reverse leakage (<0.1µA at 17V), hermetic reliability for harsh environments, and compatibility with legacy DO-35 footprint designs requiring RoHS-compliant lead-free termination.
Technical Context
This discrete Zener diode operates in reverse breakdown to maintain stable 22V regulation across varying load and temperature conditions. Its 29Ω Zener impedance at 5.6mA ensures minimal output voltage variation under dynamic current changes, while the +0.087%/°C temperature coefficient enables predictable drift compensation in analog reference circuits.
The DO-35 glass-encapsulated package provides hermetic sealing and high thermal resistance (300°C/W junction-to-ambient), requiring lead temperature control ≤75°C during soldering. Polarity is marked by a cathode band, and terminals use Sn96.5Ag3.5 finish compliant with MIL-STD-202 Method 208.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage | 22V nominal, 20.9–23.1V range at 5.6mA - defines regulated output level for feedback networks |
| Power Dissipation | 500mW - sets maximum continuous power handling without derating at ambient ≤75°C |
| Zener Impedance | 29Ω at IZT = 5.6mA - determines AC regulation sensitivity to current transients |
| Reverse Leakage | ≤0.1µA at VR = 17V - ensures minimal error current in high-impedance reference paths |
| Temp Coefficient | +0.087%/°C - quantifies voltage drift per degree Celsius for thermal design margining |
| Operating Temp | −65°C to +175°C - supports industrial, automotive under-hood, and aerospace applications |
Pinout & Package
Package: Hermetic DO-35 glass case with axial leads; cathode identified by black band; total weight ≈0.13g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reverse bias reference ground node | Connected to circuit ground or lower-potential rail in shunt regulator configuration |
| Cathode | Zener breakdown terminal / Regulated output node | Connected to input voltage source and load; delivers stable 22V reference when reverse-biased |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic Glass Package | Ensures long-term parameter stability and moisture immunity in humid or corrosive environments |
| ±5% Zener Tolerance | Enables tight voltage regulation without post-production trimming in cost-sensitive designs |
| Lead-Free RoHS Compliance | Sn96.5Ag3.5 termination meets EU Directive 2015/863/EU with full exemption documentation |
| High-Temperature Operation | Rated up to +175°C junction temperature - suitable for engine control units and downhole electronics |
Applications
| Power Supply Feedback Reference | Overvoltage Clamp Protection |
|---|---|
Use Scenario: Stabilizing output voltage in isolated flyback or forward converter feedback loops using optocoupler-coupled TL431 alternatives. IC Role / Device Role / Timing Role: Shunt voltage reference providing precise 22V threshold to control primary-side PWM duty cycle. Use Value: Maintains ±1% output regulation across line/load/temperature with no active components required. | Use Scenario: Protecting microcontroller I/O pins or ADC inputs from transient surges exceeding 22V. IC Role / Device Role / Timing Role: Fast-acting crowbar element clamping voltage spikes before damage occurs. Use Value: Limits peak voltage to 22.5V with <0.1µA leakage at 17V - preserves signal integrity in sensor interfaces. |
| Temperature-Compensated Reference | Legacy Circuit Replacement |
Use Scenario: Building a two-diode temperature-stable reference by pairing with a complementary-coefficient Zener. IC Role / Device Role / Timing Role: Primary reference element whose +0.087%/°C drift is offset by a negative-coefficient device. Use Value: Achieves <50ppm/°C net drift in precision instrumentation amplifiers and DAC buffers. | Use Scenario: Replacing obsolete 1N5251B in existing PCBs where DO-35 footprint and electrical specs match. IC Role / Device Role / Timing Role: Drop-in functional replacement maintaining identical Zener voltage, power rating, and thermal profile. Use Value: Eliminates redesign effort while meeting RoHS compliance and hermetic reliability requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMSZ5251B | Surface-mount SOD-123 package; same 22V/±5%/500mW spec but lower ZZT (25Ω) and higher IZT (20mA) | Requires PCB footprint change; better suited for automated assembly and higher-current regulation | Select for new designs prioritizing SMT yield and thermal performance on FR4 |
| 1N4748A | DO-41 package; 22V/±5%, 1W power rating, 23Ω ZZT at 19mA, −65°C to +175°C | Higher power capability but larger footprint; not hermetic - reduced long-term stability in humid environments | Select when >500mW dissipation is needed and hermeticity is non-critical |
Compared with MMSZ5251B and 1N4748A, the 1N5251B-T offers unique hermetic reliability in the legacy DO-35 form factor, making it optimal for repair, military, and high-reliability replacements where moisture resistance and footprint compatibility outweigh SMT efficiency gains.
Availability
1N5251B-T is available at Aetrix Electronics and suitable for power supply feedback reference, overvoltage clamp protection, and temperature-compensated reference applications requiring stable component supply and long-term parametric consistency.
Supply support for 1N5251B-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, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.
The 1N52xxB series belongs to Diodes' legacy Zener diode product line, engineered specifically for high-stability voltage reference and protection functions in industrial, automotive, and telecom infrastructure equipment.
FAQ
What is the maximum reverse voltage the 1N5251B-T can withstand before breakdown?
The 1N5251B-T has a nominal Zener voltage of 22V with a guaranteed range of 20.9V to 23.1V at 5.6mA test current. Breakdown begins within this range under reverse bias; operation above 23.1V risks exceeding its 500mW power limit unless current is strictly limited by external series resistance.
Is the 1N5251B-T suitable for reflow soldering?
No - the DO-35 glass package is not rated for standard reflow profiles. It requires hand-soldering or wave soldering with strict lead temperature control ≤75°C and 9.5mm lead length from case, per MIL-STD-202 Method 208, due to thermal stress vulnerability of the glass-to-metal seal.
How does the +0.087%/°C temperature coefficient impact circuit accuracy?
At 22V nominal, this coefficient causes ~19mV/°C drift. Over a 100°C range (−25°C to +75°C), total drift is ~1.9V - requiring compensation in precision references via paired Zeners or thermistors, or limiting ambient operating range to ±25°C for <0.5% error.
Why is the 1N5251B-T marked obsolete, and what is the recommended replacement?
Diodes Incorporated discontinued the 1N5251B-T in favor of the MMSZ5251B SOD-123 variant. However, Aetrix Electronics maintains legacy supply for repair and obsolescence management; the MMSZ5251B is recommended only for new designs where SMT assembly and improved Zener impedance are priorities.
1N5251B-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 22 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 29 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 17 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.1 V @ 200 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-35
1N5251B-T FAQ
1.How can I place an order for 1N5251B-T through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5251B-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 1N5251B-T reliable?
The price and inventory of 1N5251B-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5251B-T is usually 5 days.
3.What payment methods are accepted for 1N5251B-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5251B-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5251B-T?
1N5251B-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5251B-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 1N5251B-T?
For technical support, including 1N5251B-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5251B-T requirements.
6.How does Aetrix verify that 1N5251B-T is sourced from the original manufacturer or authorized distributors?
All 1N5251B-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 1N5251B-T meets industry standards.
7.What is the process for return or replacement of 1N5251B-T?
All 1N5251B-T units undergo pre-shipment inspection (PSI). If there is an issue with 1N5251B-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 1N5251B-T part is unused and in its original packaging.
Return procedure for 1N5251B-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N5251B-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…
