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Nexperia USA Inc. TL431AFDT-QR
- Part No.:
- TL431AFDT-QR
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431AFDT-QR.pdf
- Description:
- IC VREF SHUNT 2.495V SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,788
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Product details
Overview
TL431AFDT-QR 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 automotive-grade isolated DC-DC converters.
For engineers reviewing the TL431AFDT-QR datasheet, TL431AFDT-QR pinout, TL431AFDT-QR application, or TL431AFDT-QR equivalent, this page delivers verified electrical specs, thermal derating curves, mirrored-pin SOT23 layout, automotive qualification status (AEC-Q100 Grade 1), and real-world SMPS feedback use cases - all extracted from Nexperia's Rev. 2 (30 April 2024) product data sheet.
Technical Context
The TL431AFDT-QR implements a bandgap-referenced error amplifier with active output stage, enabling sharp turn-on and low dynamic impedance (0.2 Ω typical). Its reference node (REF) senses external resistor dividers to regulate cathode-anode voltage between 2.495 V and 36 V.
It operates in shunt mode with 2 µA to 4 µA reference input current and supports stable closed-loop control up to 100 kHz bandwidth. The device uses mirrored pinning (REF–K–A) and is qualified per AEC-Q100 Grade 1 for under-hood automotive environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference voltage (Vref) | 2.495 V ±1.0 % at IK = 10 mA, Tamb = 25 °C - sets precise regulation threshold via external resistors |
| Cathode current range | 1 mA to 100 mA - enables direct sinking into feedback optocoupler LEDs or series pass transistors |
| Dynamic cathode-anode impedance | 0.2 Ω typical (f < 1 kHz) - ensures minimal output perturbation during load transients in SMPS loops |
| Temperature range | –40 °C to +125 °C - validated for engine control units, battery management, and ADAS power rails |
| Output noise | Low - supports stable regulation without added filtering in compact space-constrained designs |
| AEC-Q100 qualification | Grade 1 (–40 °C to +125 °C) - meets automotive reliability requirements for safety-critical subsystems |
| Package | SOT23 - surface-mount footprint compatible with standard reflow profiles and wave soldering |
Pinout & Package
SOT23 plastic surface-mounted package (3 leads), 1.9 mm × 1.1 mm × 1.0 mm body, mirrored pinning configuration (REF–K–A).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | REF | Reference input - connects to resistor divider midpoint; high-impedance node (2–4 µA bias) |
| 2 | K | Cathode - sinks regulated current; connects to SMPS optocoupler anode or series pass transistor base |
| 3 | A | Anode - ties to system ground or return path; forms cathode-anode voltage (VKA) across device |
Key Features
| Feature | Design Value |
|---|---|
| Programmable output voltage | 2.495 V to 36 V - set by two external resistors; eliminates need for multiple fixed-voltage references |
| A-grade tolerance | ±1.0 % at 25 °C - tighter than standard TL431 (±2.0 %), reducing output drift in precision feedback paths |
| Low temperature drift | ±9 mV over 0 °C to 70 °C - maintains regulation accuracy across cabin temperature gradients |
| Low output impedance | 0.2 Ω typical - minimizes voltage deviation during fast current changes in isolated flyback controllers |
| Automotive qualification | AEC-Q100 Grade 1 - certified for under-hood deployment without additional burn-in or screening |
Applications
| Shunt Regulator | Precision Current Limiter |
|---|---|
Use Scenario: Stabilizing 5 V rail in automotive infotainment head unit using resistor divider and bypass capacitor. IC Role / Device Role / Timing Role: Shunt regulator - sinks excess current to maintain constant VKA at 5.0 V. Use Value: Replaces discrete Zener + transistor combo; reduces BOM count and improves thermal stability over temperature. |
Use Scenario: Limiting charging current to 200 mA in 12 V LiFePO4 battery module. IC Role / Device Role / Timing Role: Precision current limiter - REF senses voltage across sense resistor; K sinks current to clamp IOUT. Use Value: Achieves ±1 % current accuracy across –40 °C to +85 °C without calibration. |
| Isolated Feedback Loop | Precision Constant Current Sink |
Use Scenario: Secondary-side voltage sensing in 36 W automotive AC/DC adapter with optocoupler coupling. IC Role / Device Role / Timing Role: Isolated feedback loop element - drives optocoupler LED to transmit error signal across isolation barrier. Use Value: Enables <1 % output voltage regulation despite transformer leakage and optocoupler CTR variation. |
Use Scenario: Biasing laser diode in ADAS LIDAR transmitter with stable 80 mA current. IC Role / Device Role / Timing Role: Precision constant current sink - REF tied to sense resistor; K sinks fixed current independent of supply ripple. Use Value: Delivers <0.5 % current stability over 12 V ±15 % input and 85 °C ambient - critical for optical output consistency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BFDT-Q | 0.5 % reference tolerance (vs. 1.0 %); otherwise identical pinout, package, and temp range | Used where tighter initial accuracy required (e.g., factory-calibrated sensors), but adds cost | Select when ±0.5 % Vref is mandatory and budget allows premium grade |
| TL431AFDT | Same electrical specs but non-automotive grade (no AEC-Q100 qualification) | Suitable for industrial/commercial power supplies where automotive reliability not mandated | Choose for cost-sensitive non-automotive designs requiring same performance without qualification overhead |
Compared with TL431AFDT-QR, TL431BFDT-Q offers higher initial accuracy at increased cost and no change in thermal or dynamic behavior, while TL431AFDT provides identical functionality without AEC-Q100 validation - making TL431AFDT-QR the optimal choice for automotive feedback systems requiring both precision and qualification assurance.
Availability
TL431AFDT-QR is available at Aetrix Electronics and suitable for automotive power conversion, battery management systems, and isolated DC-DC converter feedback loops requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL431AFDT-QR 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 leading semiconductor manufacturer headquartered in Nijmegen, Netherlands, specializing in high-volume logic, analog, and discrete components with focus on automotive, industrial, and mobile markets.
The TL431-Q family is part of Nexperia's automotive-qualified analog portfolio, designed specifically to replace Zener diodes in safety-critical feedback, current limiting, and voltage reference applications across harsh-temperature automotive subsystems.
FAQ
What is the pin configuration of TL431AFDT-QR?
TL431AFDT-QR uses mirrored pinning in SOT23: Pin 1 = REF (reference input), Pin 2 = K (cathode), Pin 3 = A (anode). This differs from standard TL431 pinouts (K–REF–A) and must be verified in PCB layout to avoid functional failure.
Does TL431AFDT-QR require an external capacitor on the REF pin?
Yes - a 100 pF capacitor is recommended between REF and A (ground) to suppress high-frequency noise injection from primary-side switching in SMPS feedback circuits, preventing instability or oscillation observed above 100 kHz.
How does TL431AFDT-QR behave below minimum cathode current?
Below 0.4 mA (typical IK(min)), regulation degrades significantly: VKA rises unpredictably and reference accuracy collapses. Designers must ensure external circuitry guarantees ≥1 mA cathode current under all operating conditions, including light-load or standby modes.
Can TL431AFDT-QR drive an optocoupler LED directly?
Yes - with 1 mA to 100 mA sink capability and 0.2 Ω dynamic impedance, TL431AFDT-QR directly interfaces with common PC817/PC817x optocouplers. Typical design uses 1 kΩ series resistor from cathode to LED anode, delivering ~5–10 mA LED current at 5 V output.
TL431AFDT-QR 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:
- SOT-23-3 (TO-236)
TL431AFDT-QR FAQ
1.How can I place an order for TL431AFDT-QR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431AFDT-QR 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-QR reliable?
The price and inventory of TL431AFDT-QR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431AFDT-QR is usually 5 days.
3.What payment methods are accepted for TL431AFDT-QR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431AFDT-QR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431AFDT-QR?
TL431AFDT-QR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431AFDT-QR 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-QR?
For technical support, including TL431AFDT-QR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431AFDT-QR requirements.
6.How does Aetrix verify that TL431AFDT-QR is sourced from the original manufacturer or authorized distributors?
All TL431AFDT-QR 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-QR meets industry standards.
7.What is the process for return or replacement of TL431AFDT-QR?
All TL431AFDT-QR units undergo pre-shipment inspection (PSI). If there is an issue with TL431AFDT-QR, 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-QR part is unused and in its original packaging.
Return procedure for TL431AFDT-QR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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