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onsemi 1N5985B_T50R
- Part No.:
- 1N5985B_T50R
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N5985B_T50R.pdf
- Description:
- DIODE ZENER 2.4V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:8,120
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Product details
Overview
1N5985B_T50R from Fairchild Semiconductor is a 2.4 V ±5% Zener diode in DO-35 glass package, rated for 500 mW power dissipation at TL ≤ 75°C with 100 Ω zener impedance at 5 mA test current and 100 μA leakage current at 1 V reverse bias. It serves as a precision voltage reference or overvoltage clamp in low-power analog circuits.
For engineers reviewing the 1N5985B_T50R datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, cathode identification, and direct-fit alternatives for stable voltage regulation in space-constrained designs.
Technical Context
This Zener diode operates in reverse breakdown mode with a nominal zener voltage of 2.4 V measured at 5 mA test current and 30°C lead temperature. Its 100 Ω dynamic impedance at IZ and 1800 Ω knee impedance at 250 μA define regulation sharpness and low-current stability.
The device features a -65°C to +200°C operating and storage temperature range, 4.0 mW/°C thermal derating above 75°C, and forward voltage ≤1.2 V at 200 mA - enabling bidirectional protection and compatibility with TTL logic level sensing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 2.4 V min / 2.58 V typ / 2.52 V max @ 5 mA - defines tight 5% tolerance band for stable reference generation |
| Power Dissipation (PD) | 500 mW @ TL ≤ 75°C - sets maximum continuous power handling before thermal derating begins |
| Zener Impedance (ZZ) | 100 Ω @ 5 mA - determines output voltage variation under load current changes |
| Knee Impedance (ZZK) | 1800 Ω @ 250 μA - indicates regulation onset threshold and low-current stability limit |
| Leakage Current (IR) | 100 μA @ 1 V reverse - quantifies off-state conduction affecting high-impedance bias networks |
| Operating Temp Range | -65°C to +200°C - supports deployment in automotive under-hood, industrial, and aerospace environments |
Pinout & Package
DO-35 glass axial package with cathode identified by a single color band on the body. Leads are tinned copper-clad steel, 3/8″ length specified for thermal rating compliance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reverse breakdown reference ground node | Connected to circuit ground or lower potential; enables clamping when cathode is biased above anode |
| Cathode | Zener voltage reference terminal / Reverse breakdown input | Marked with color band; connected to regulated voltage node or overvoltage sensing point |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Ensures predictable regulation across production lots without post-assembly trimming |
| DO-35 glass hermetic package | Provides long-term reliability and moisture resistance in harsh ambient conditions |
| 100 μA leakage at 1 V | Minimizes error in high-impedance reference dividers and battery-monitoring circuits |
| 1.2 V forward voltage max | Allows use as bidirectional ESD clamp or polarity-insensitive protection element |
Applications
| Low-Voltage Reference | Overvoltage Clamp |
|---|---|
Use Scenario: Providing stable 2.4 V bias for op-amp comparators and ADC reference inputs in battery-powered sensors. IC Role / Device Role / Timing Role: Precision voltage reference source establishing analog signal thresholds. Use Value: Tight 5% tolerance and low 100 Ω impedance ensure <±10 mV drift under 1 mA load variation. |
Use Scenario: Protecting microcontroller I/O pins from transient surges exceeding 3.3 V rail in industrial control modules. IC Role / Device Role / Timing Role: Shunt overvoltage protection device clamping excess energy to ground. Use Value: Fast 2.4 V breakdown onset limits voltage excursion before damage occurs to downstream CMOS inputs. |
| Battery Voltage Monitor | TTL-Level Signal Conditioning |
Use Scenario: Detecting end-of-discharge in 3 V lithium coin cells used in wearables and medical patches. IC Role / Device Role / Timing Role: Threshold detector comparing cell voltage against fixed 2.4 V reference. Use Value: Low 100 μA leakage preserves battery life over multi-year deployments. |
Use Scenario: Level-shifting 5 V logic signals down to 2.4 V for interfacing with legacy 2.5 V tolerant peripherals. IC Role / Device Role / Timing Role: Passive voltage translation element using Zener forward conduction. Use Value: Forward voltage ≤1.2 V enables reliable low-drop operation without active circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N5221B | 2.4 V nominal, same 5% tolerance, but rated for 500 mW at 25°C (no explicit TL derating curve) | Lacks documented thermal derating above 75°C; less suitable for high-ambient-temperature PCBs | Select 1N5221B only when ambient temperature remains below 60°C and lead length is unrestricted |
| BZX55C2V4 | 2.4 V nominal, 5% tolerance, DO-35 package, but 600 mW rating and 150 Ω ZZ @ 5 mA | Higher power margin and slightly higher impedance; requires verification of thermal layout compatibility | Prefer BZX55C2V4 where board-level heat sinking supports >500 mW dissipation and 150 Ω impedance is acceptable |
Compared with 1N5985B_T50R, 1N5221B offers identical voltage but weaker thermal specification traceability, while BZX55C2V4 provides higher power headroom at the cost of reduced regulation precision - making 1N5985B_T50R optimal for thermally constrained, low-impedance reference designs.
Availability
1N5985B_T50R is available at Aetrix Electronics and suitable for low-power voltage reference, overvoltage protection, and battery monitoring applications requiring stable component supply and long-lifecycle support.
Supply support for 1N5985B_T50R 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.
The 1N5985B_T50R belongs to Fairchild's legacy 1N59xxB Zener diode family, engineered for general-purpose voltage regulation and clamping in cost-sensitive, high-reliability consumer and industrial systems.
FAQ
What is the exact Zener voltage tolerance of the 1N5985B_T50R?
The 1N5985B_T50R has a guaranteed ±5% Zener voltage tolerance, with a minimum value of 2.4 V, typical value of 2.58 V, and maximum value of 2.52 V - all specified at 5 mA test current and 30°C lead temperature. This tolerance band ensures consistent performance across manufacturing lots without calibration.
Does the 1N5985B_T50R support operation above 75°C ambient?
Yes, the 1N5985B_T50R supports operation up to +200°C junction temperature, but its power dissipation must be derated linearly at 4.0 mW/°C above 75°C lead temperature. At 100°C lead temperature, maximum allowable power drops to 400 mW, requiring careful thermal design of PCB traces and lead length.
How is cathode polarity identified on the 1N5985B_T50R package?
The cathode of the 1N5985B_T50R is marked by a single color band on the DO-35 glass body. Per Fairchild documentation, this band aligns with the cathode terminal, and the unmarked end is the anode. The marking matches industry-standard DO-35 orientation used across Zener diode families.
What is the forward voltage specification for the 1N5985B_T50R?
The 1N5985B_T50R has a maximum forward voltage of 1.2 V at 200 mA forward current. This parameter enables its use in bidirectional protection schemes and low-voltage level-shifting applications where forward conduction is intentionally utilized alongside reverse breakdown behavior.
Can the 1N5985B_T50R replace the 1N4728A in existing designs?
No - the 1N4728A is a 3.3 V Zener diode, whereas the 1N5985B_T50R is rated at 2.4 V. Substituting them would shift reference or clamp thresholds by nearly 1 V, causing functional failure in circuits relying on precise voltage levels. Always verify voltage match before replacement.
1N5985B_T50R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 2.4 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 100 Ohms
- Current - Reverse Leakage @ Vr:
- 100 µA @ 1 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-35
1N5985B_T50R FAQ
1.How can I place an order for 1N5985B_T50R through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5985B_T50R 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 1N5985B_T50R reliable?
The price and inventory of 1N5985B_T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5985B_T50R is usually 5 days.
3.What payment methods are accepted for 1N5985B_T50R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5985B_T50R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5985B_T50R?
1N5985B_T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5985B_T50R 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 1N5985B_T50R?
For technical support, including 1N5985B_T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5985B_T50R requirements.
6.How does Aetrix verify that 1N5985B_T50R is sourced from the original manufacturer or authorized distributors?
All 1N5985B_T50R 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 1N5985B_T50R meets industry standards.
7.What is the process for return or replacement of 1N5985B_T50R?
All 1N5985B_T50R units undergo pre-shipment inspection (PSI). If there is an issue with 1N5985B_T50R, 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 1N5985B_T50R part is unused and in its original packaging.
Return procedure for 1N5985B_T50R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N5985B_T50R Tags
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MMBZ5240B-7-F
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