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Nexperia USA Inc. TL431AFDT/8R
- Part No.:
- TL431AFDT/8R
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431AFDT/8R.pdf
- Description:
- IC VREF SHUNT ADJ 1% TO236AB
- Quantity:
- Payment:
- Shipping:
Inventory:2,907
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Product details
Overview
TL431AFDT/8R from Nexperia is an A-grade (±1.0 %) adjustable precision shunt regulator in SOT23 package, featuring 2.495 V reference voltage, 1 mA to 100 mA sink current capability, and operation across –40 °C to +125 °C. It functions as a programmable voltage reference or error amplifier in feedback loops of isolated DC-DC converters and precision current sinks.
For engineers reviewing the TL431AFDT/8R datasheet, TL431AFDT/8R pinout, TL431AFDT/8R application, or TL431AFDT/8R equivalent, this page delivers verified electrical parameters, validated SOT23 pin mapping, confirmed automotive-grade thermal performance, and real-world use cases in SMPS feedback and constant-current regulation.
Technical Context
The TL431AFDT/8R implements a three-terminal shunt regulator architecture with internal bandgap reference, error amplifier, and NPN output stage. Its cathode-anode voltage range spans 2.495 V to 36 V, set externally via two resistors, and it maintains ±1.0 % reference accuracy over –40 °C to +125 °C.
It delivers low dynamic impedance (0.2 Ω typical), sharp turn-on behavior, and stable operation up to 100 mA sink current. The device supports isolated feedback topologies by sourcing reference current (2–4 μA typical) into the REF pin while sinking load current at the cathode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference voltage (Vref) | 2495 mV ±1.0 % at IK = 10 mA, Tamb = 25 °C - sets precise regulation threshold |
| Cathode current range | 1 mA to 100 mA - enables direct replacement of Zener diodes in high-current shunt applications |
| Dynamic cathode-anode impedance | 0.2 Ω typical below 1 kHz - ensures minimal output voltage perturbation under load transients |
| Reference current (Iref) | 2–4 μA typical - low input bias enables high-resistance external resistor networks without accuracy loss |
| Temperature range | –40 °C to +125 °C - qualified for industrial and extended-temperature embedded power systems |
| Output noise | Low - specified via low output impedance and internal compensation, enabling clean feedback signals |
| Cathode-anode voltage max | 36 V - supports regulation in 24 V and 32 V bus systems with margin |
Pinout & Package
SOT23 plastic surface-mounted package (3 leads), 1.9 mm × 1.1 mm footprint, 0.95 mm height, with standard pinning configuration (K-REF-A).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - K (Cathode) | Sink output terminal | Carries regulated load current; connects to primary-side return in isolated SMPS feedback |
| 2 - REF (Reference) | High-impedance input | Accepts voltage divider feedback; draws only 2–4 μA, enabling high-R network design |
| 3 - A (Anode) | Return path | Connects to system ground or low-side rail; completes shunt current path |
Key Features
| Feature | Design Value |
|---|---|
| Programmable output voltage | 2.495 V to 36 V via two external resistors - eliminates need for multiple fixed-voltage references |
| A-grade reference tolerance | ±1.0 % over full temperature range - enables tighter output regulation than standard-grade TL431 variants |
| Low output impedance | 0.2 Ω typical - minimizes voltage droop during fast load steps in precision current sinks |
| Sharp turn-on characteristic | Active output stage with fast response - improves transient immunity vs. passive Zener diodes |
| ESD robustness | 4 kV HBM - enhances reliability in handling and board assembly environments |
Applications
| Isolated SMPS Feedback | Precision Current Sink |
|---|---|
|
Use Scenario: Secondary-side voltage sensing in flyback or forward converters with optocoupler-coupled feedback. IC Role / Device Role / Timing Role: Shunt regulator providing stable 2.495 V reference to drive optocoupler LED; error amplifier comparing output voltage against Vref. Use Value: Enables ±1 % output regulation across line/load/temperature; replaces discrete op-amp + Zener solutions with single-component simplicity. |
Use Scenario: Constant-current source for LED biasing or sensor excitation in industrial analog front-ends. IC Role / Device Role / Timing Role: Precision shunt element controlling current through external pass transistor or load resistor. Use Value: Delivers <1 % current accuracy over –40 °C to +125 °C using only two resistors and one transistor - no trimming required. |
| Adjustable Voltage Reference | Overvoltage Protection Threshold |
|
Use Scenario: Programmable reference for ADCs, comparators, or DACs in battery-powered instrumentation. IC Role / Device Role / Timing Role: Adjustable voltage source generating stable reference from unregulated supply rails. Use Value: Supports 2.495–36 V range with ±1.0 % tolerance - eliminates need for multiple fixed references or trimming potentiometers. |
Use Scenario: Threshold detector in DC bus monitoring for telecom or server power supplies. IC Role / Device Role / Timing Role: Comparator input reference for overvoltage latch circuits using external transistor switch. Use Value: Provides temperature-stable trip point (e.g., 28.5 V ±0.285 V) without drift-induced false triggers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BFDTR | ±0.5 % reference tolerance, same SOT23 package and pinout | Higher accuracy needed for <0.5 % output regulation; tighter thermal drift spec | Select when absolute reference stability dominates cost sensitivity |
| TL431ACDBZR | SOT23-3, same A-grade tolerance, but rated for 0 °C to +70 °C only | Limited to commercial-temperature applications; lower thermal derating margin | Choose for cost-sensitive consumer designs where extended temperature range is unnecessary |
Compared with TL431AFDT/8R, TL431BFDTR offers higher accuracy at the expense of slightly higher unit cost and identical thermal envelope, while TL431ACDBZR reduces qualification scope to commercial temperature - making it unsuitable for industrial or automotive ambient conditions despite matching electrical grade.
Availability
TL431AFDT/8R is available at Aetrix Electronics and suitable for isolated SMPS feedback, precision current sink, and adjustable voltage reference applications requiring stable component supply across industrial temperature ranges.
Supply support for TL431AFDT/8R 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
Nexperia is a global semiconductor expert delivering high-performance logic, analog, and MOSFET solutions with focus on efficiency, reliability, and miniaturization.
The TL431 family is designed for precision voltage regulation in power management subsystems - targeting cost-sensitive yet thermally demanding applications in industrial, telecom, and computing infrastructure.
FAQ
What is the maximum cathode-anode voltage for TL431AFDT/8R?
The absolute maximum cathode-anode voltage is 37 V per datasheet limiting values. Continuous operation is recommended up to 36 V, as specified in recommended operating conditions. Exceeding 37 V risks permanent damage due to junction breakdown.
Does TL431AFDT/8R require an external capacitor on the REF pin?
Yes - a small capacitor (~100 pF) is recommended directly at the REF pin to suppress high-frequency noise coupling from the primary side in isolated SMPS applications. This prevents instability or false triggering in feedback loops.
Can TL431AFDT/8R replace a Zener diode directly?
Yes, in most shunt regulator configurations - but only if the Zener's voltage matches the programmed Vref and its power dissipation is within TL431AFDT/8R's 350–950 mW thermal limits. Unlike Zeners, TL431AFDT/8R requires a minimum 1 mA cathode current to regulate.
Is TL431AFDT/8R qualified for automotive use?
No - although earlier revisions included AEC-Q100 Grade 1 qualification, Revision 8 (2025) explicitly removed automotive qualification status for TL431AFDT/8R. It remains suitable for industrial and extended-temperature applications up to +125 °C.
TL431AFDT/8R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.495V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 600 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-236AB
TL431AFDT/8R FAQ
1.How can I place an order for TL431AFDT/8R through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431AFDT/8R 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 TL431AFDT/8R reliable?
The price and inventory of TL431AFDT/8R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431AFDT/8R is usually 5 days.
3.What payment methods are accepted for TL431AFDT/8R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431AFDT/8R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431AFDT/8R?
TL431AFDT/8R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431AFDT/8R 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 TL431AFDT/8R?
For technical support, including TL431AFDT/8R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431AFDT/8R requirements.
6.How does Aetrix verify that TL431AFDT/8R is sourced from the original manufacturer or authorized distributors?
All TL431AFDT/8R 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 TL431AFDT/8R meets industry standards.
7.What is the process for return or replacement of TL431AFDT/8R?
All TL431AFDT/8R units undergo pre-shipment inspection (PSI). If there is an issue with TL431AFDT/8R, 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 TL431AFDT/8R part is unused and in its original packaging.
Return procedure for TL431AFDT/8R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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