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Texas Instruments TL431ACD
- Part No.:
- TL431ACD
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431ACD.pdf
- Description:
- IC VREF SHUNT ADJ 1% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,055
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Product details
Overview
TL431ACD from STMicroelectronics is an AEC-Q100 qualified, adjustable shunt voltage reference IC with 1% initial voltage precision (2.5 V nominal), operating over -40 °C to +125 °C, supporting 1–100 mA sink current and delivering 0.22 Ω typical dynamic impedance - used in automotive power supply feedback loops and industrial voltage regulation circuits.
For engineers reviewing the TL431ACD datasheet, TL431ACD pinout, TL431ACD application, or TL431ACD equivalent, this page provides verified pin functions, temperature-stable reference performance data, automotive-grade thermal specs, and validated alternative options for precision voltage setting in closed-loop regulator designs.
Technical Context
The TL431ACD implements a three-terminal adjustable shunt regulator architecture: its internal bandgap reference and error amplifier compare the external resistor-divided cathode voltage against a 2.5 V reference, driving the output transistor to maintain regulation. It operates as a programmable Zener replacement with active feedback control.
It supports wide-cathode-voltage operation (2.5–36 V) via two external resistors, maintains stable regulation across ±100 mA cathode current range, and achieves <±7 mV total reference deviation over -40 °C to +125 °C - confirmed per AEC-Q100 Grade 1 qualification.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.5 V ±1% at 25 °C; sets precise feedback threshold for SMPS and LDO error amplifiers |
| Output Voltage Range | 2.5–36 V via external R1/R2 divider; enables flexible regulation without discrete Zeners |
| Sink Current Range | 1–100 mA; supports direct drive of optocoupler LEDs or secondary-side feedback in isolated converters |
| Dynamic Impedance | 0.22 Ω typical; ensures minimal output voltage perturbation under load transients |
| Temp. Range | -40 °C to +125 °C; certified for under-hood automotive and industrial high-ambient environments |
| Voltage Deviation | ±7 mV max over full temp range; guarantees tight loop stability in critical feedback paths |
| Reference Input Current | ≤4 µA typical; minimizes resistor-divider loading error in high-impedance setpoint networks |
Pinout & Package
TL431ACD is supplied in SO-8 (batwing plastic micropackage), a surface-mount 8-pin package with exposed thermal pad for enhanced power dissipation in automotive applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Anode) | Anode terminal | Low-side return path; connects to ground or common reference node in shunt configuration |
| 2 (Cathode) | Cathode terminal | High-current output node; sinks regulated current to maintain reference voltage at REF pin |
| 3 (REF) | Reference input | Feedback sense node; connected to resistor divider midpoint to set output voltage |
| 4–8 (NC) | No-connect terminals | Internally unconnected; must remain floating or tied to GND per layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for automotive use with full temperature cycling, HTOL, and ESD testing per ISO/TS 16949 |
| Adjustable 2.5–36 V output | Enables single-part reuse across multiple rail voltages without redesigning feedback network |
| 0.22 Ω dynamic impedance | Reduces output ripple sensitivity and improves transient response in switching regulator feedback |
| 1% initial voltage accuracy | Eliminates need for post-production trimming in cost-sensitive automotive and industrial modules |
| 1–100 mA cathode current range | Supports direct optocoupler drive in flyback PSUs without external transistor buffering |
Applications
| Automotive DC-DC Converter | Industrial SMPS Feedback |
|---|---|
Use Scenario: Secondary-side voltage regulation in isolated 12 V → 5 V/3.3 V flyback converter for ADAS camera module. IC Role / Device Role / Timing Role: Shunt reference providing precise feedback signal to optocoupler, enabling primary-side PWM controller adjustment. Use Value: Maintains ±1% output tolerance over -40 °C to +125 °C ambient, meeting ASIL-B functional safety margin requirements. |
Use Scenario: Output voltage sensing in 48 V telecom rectifier with remote sense capability. IC Role / Device Role / Timing Role: Adjustable reference node in high-impedance resistor divider, interfacing with error amplifier input. Use Value: 0.22 Ω dynamic impedance prevents gain shift during load steps, preserving loop phase margin above 45°. |
| Programmable Overvoltage Protection | Lab Bench Power Supply |
Use Scenario: Threshold detector in battery management system guarding against 28 V overvoltage in 24 V truck systems. IC Role / Device Role / Timing Role: Precision voltage comparator reference feeding into external op-amp or comparator input. Use Value: ±7 mV reference deviation ensures trip point remains within ±0.3% across full vehicle temperature profile. |
Use Scenario: Adjustable voltage setpoint in digitally controlled bench PSU with analog feedback loop. IC Role / Device Role / Timing Role: Programmable reference source for DAC-controlled output voltage scaling. Use Value: 1% initial accuracy and low IREF (≤4 µA) minimize DAC output error and reduce divider power loss. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDR | 0.5% initial accuracy, same SO-8 package, identical -40 °C to +125 °C range | Higher precision required in medical-grade power supplies where ±0.5% output tolerance is mandated | Select when tighter initial voltage tolerance is needed without changing PCB layout or thermal design |
| TLVH431ACDBVR | Lower 1.24 V reference, 1% accuracy, SOT-23-3 package, 1–80 mA sink current | Used in space-constrained low-voltage rails (e.g., 3.3 V FPGA core supplies) where 2.5 V reference is excessive | Choose for compact footprint and lower reference voltage; verify cathode voltage headroom compatibility |
Compared with TL431ACD, TL431BIDR offers higher precision at identical thermal and package specs, while TLVH431ACDBVR trades reference voltage and package size for board area reduction - both require validation of cathode current compliance and thermal derating in target layouts.
Availability
TL431ACD is available at Aetrix Electronics and suitable for automotive power supply design, industrial SMPS feedback networks, and programmable overvoltage protection circuits requiring stable component supply with AEC-Q100 traceability.
Supply support for TL431ACD 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, power, microcontroller, and sensor solutions for automotive, industrial, and consumer markets.
The TL431 product line delivers precision, temperature-stable shunt references optimized for closed-loop voltage regulation in harsh-environment power systems - especially where AEC-Q100 compliance and long-term parametric stability are mandatory.
FAQ
What is the maximum cathode-to-anode voltage for TL431ACD?
The absolute maximum cathode-to-anode voltage (VKA) is 37 V. Operation beyond this risks permanent device damage. In normal use, the cathode voltage is set between 2.5 V and 36 V via external resistors - staying within the 37 V limit ensures safe, reliable regulation across all operating conditions.
Can TL431ACD replace a Zener diode in existing designs?
Yes - TL431ACD functions as a programmable, high-precision Zener substitute. Unlike fixed Zeners, it allows adjustable output (2.5–36 V) with superior temperature stability (±7 mV over -40 °C to +125 °C) and lower dynamic impedance (0.22 Ω). External resistor selection determines voltage, eliminating need for multiple Zener part numbers.
Is thermal derating required for TL431ACD in SO-8 package?
Yes - SO-8 package has junction-to-ambient thermal resistance (RthJA) of 85 °C/W. At 100 mA sink current and 36 V cathode voltage, power dissipation reaches 3.6 W, requiring heatsinking or ambient derating. Derate linearly above 25 °C ambient using RthJA to ensure junction temperature stays ≤150 °C.
Does TL431ACD support capacitive loads on the cathode?
Yes, but stability depends on capacitance value and ESR. The datasheet confirms stable operation with ≥10 µF ceramic output capacitance when used with appropriate series resistance. For >100 µF or low-ESR polymer caps, add a 1–10 Ω isolation resistor in series with the cathode to prevent oscillation - verified in Figure 21 of ST's DocID4467 Rev 17.
TL431ACD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tube
- 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TL431ACD FAQ
1.How can I place an order for TL431ACD through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431ACD 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 TL431ACD reliable?
The price and inventory of TL431ACD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431ACD is usually 5 days.
3.What payment methods are accepted for TL431ACD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431ACD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431ACD?
TL431ACD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431ACD 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 TL431ACD?
For technical support, including TL431ACD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431ACD requirements.
6.How does Aetrix verify that TL431ACD is sourced from the original manufacturer or authorized distributors?
All TL431ACD 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 TL431ACD meets industry standards.
7.What is the process for return or replacement of TL431ACD?
All TL431ACD units undergo pre-shipment inspection (PSI). If there is an issue with TL431ACD, 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 TL431ACD part is unused and in its original packaging.
Return procedure for TL431ACD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431ACD Tags
-
TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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AN431AN-ATRG1
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LM4040CYM3-2.5-TR
Microchip Technology
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LM4040CYM3-4.1-TR
Microchip Technology
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LM4040EIM3-2.5/NOPB
Texas Instruments
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AZ431LBNTR-G1
Diodes Incorporated
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LM4040D20IDBZR
Texas Instruments
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LM4041DIM3-ADJ/NOPB
Texas Instruments
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LM4040DIM3X-2.5/NOPB
Texas Instruments
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LM4040DIM3-2.5/NOPB
Texas Instruments
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AZ431LANTR-G1
Diodes Incorporated
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