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STMicroelectronics TL431AIDT
- Part No.:
- TL431AIDT
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431AIDT.pdf
- Description:
- IC VREF SHUNT ADJ 1% 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:38,163
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Product details
Overview
TL431AIDT from STMicroelectronics is an AEC-Q100 qualified automotive-grade adjustable shunt voltage reference IC, functioning as a precision 2.5 V reference with programmable output (2.5–36 V) via external resistors. It delivers 1–100 mA sink current, exhibits 0.22 Ω typical dynamic impedance, and maintains 1% initial voltage accuracy across –40 °C to +105 °C - used in feedback loops of isolated DC-DC converters and battery management systems.
For engineers reviewing the TL431AIDT datasheet, TL431AIDT pinout, TL431AIDT application, or TL431AIDT equivalent, key selection criteria include its automotive temperature range, low dynamic impedance for stable regulation, 1% reference accuracy, and SO-8 batwing package compatibility with high-reliability power supply designs.
Technical Context
The TL431AIDT implements a three-terminal adjustable shunt regulator architecture with internal bandgap reference, error amplifier, and NPN output stage. Its cathode-anode conduction is controlled by the reference input (REF) voltage relative to the 2.5 V internal threshold, enabling precise closed-loop voltage regulation without external op-amps.
It operates over 1–100 mA cathode current with guaranteed stability into capacitive loads up to 10 µF, and features –40 °C to +105 °C operating range, 0.5% typical reference deviation over temperature, and <1 µA reference input current - making it suitable for automotive power supply feedback where thermal drift and load transients must be tightly managed.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.5 V nominal, ±1% initial tolerance - sets absolute accuracy baseline for programmable output voltage calibration. |
| Output Voltage Range | 2.5 V to 36 V (externally set) - enables flexible feedback design for 3.3 V, 5 V, 12 V, 24 V, and 36 V power rails. |
| Sink Current Range | 1 mA to 100 mA - supports direct drive of optocoupler LEDs or error amplifier inputs without external buffering. |
| Dynamic Impedance | 0.22 Ω typical - ensures minimal output voltage perturbation under fast load transients in SMPS feedback paths. |
| Operating Temperature | –40 °C to +105 °C - certified for under-hood automotive applications including engine control units and ADAS power supplies. |
| Voltage Tempco | ±7 mV max deviation over full temp range - guarantees <0.03% /°C drift for stable regulation in wide-temperature environments. |
| Cathode-Anode Max Voltage | 37 V - allows safe operation with 36 V input rails plus margin, supporting 24 V and 36 V industrial and automotive systems. |
Pinout & Package
TL431AIDT is housed in an SO-8 "batwing" plastic micropackage (ECOPACK® compliant), offering enhanced thermal dissipation (RthJA = 85 °C/W) and mechanical robustness for automotive PCB assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Anode) | Anode terminal | Connects to system ground or low-side return path; sinks current when REF exceeds 2.5 V. |
| 2 (Cathode) | Cathode terminal | High-side output node; connects to feedback divider top and power rail - carries full regulated sink current. |
| 3 (REF) | Reference input | High-impedance input (≤4 µA) sensing voltage from external resistor divider; triggers regulation at 2.5 V threshold. |
| 4–8 (NC) | No-connect terminals | Internally unconnected; electrically isolated - must remain floating or tied to ground per layout best practices. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualification | Validated for automotive use (Grade 2: –40 °C to +105 °C), including HTOL, ESD, and temperature cycling tests. |
| Adjustable 2.5–36 V output | Enables single BOM part to support multiple output voltages using only two external resistors - reduces inventory and design complexity. |
| 0.22 Ω dynamic impedance | Minimizes output voltage sag during transient load steps, improving transient response in flyback and forward converter feedback loops. |
| 1% initial voltage accuracy | Reduces need for post-production trimming in production power supplies - improves yield and lowers test cost. |
| Stable into 10 µF capacitive load | Eliminates need for external compensation in most optocoupler-based isolated feedback circuits - simplifies layout and saves board space. |
Applications
| Automotive Power Supply Feedback | Industrial Isolated DC-DC Converter |
|---|---|
Use Scenario: Regulating 12 V output in a vehicle's body control module (BCM) power supply with optocoupler-coupled feedback. IC Role / Device Role / Timing Role: Adjustable shunt reference providing precise 2.5 V threshold to control optocoupler LED current and thus primary-side PWM duty cycle. Use Value: Maintains ±1.2% output regulation over –40 °C to +105 °C ambient, meeting ISO 16750-2 requirements for automotive voltage stability. | Use Scenario: Secondary-side voltage regulation in a 48 V to 5 V isolated flyback converter for factory automation I/O modules. IC Role / Device Role / Timing Role: Shunt reference generating error signal proportional to output deviation, driving optocoupler to adjust primary controller timing. Use Value: 0.22 Ω dynamic impedance ensures <10 mV output deviation during 1 A/µs load transients - critical for PLC analog input stability. |
| Battery Management System Reference | Programmable Lab Power Supply |
Use Scenario: Precision voltage reference for cell voltage monitoring and balancing circuitry in 12-cell Li-ion battery packs. IC Role / Device Role / Timing Role: Programmable reference setting threshold for overvoltage protection comparators and ADC reference scaling. Use Value: ±7 mV max reference drift over temperature ensures ≤0.5% cell voltage measurement error across full pack operating range. | Use Scenario: Core reference element in a benchtop 0–30 V, 0–3 A linear power supply with digital voltage programming. IC Role / Device Role / Timing Role: Adjustable shunt reference defining output setpoint via DAC-controlled resistor network. Use Value: 1% initial accuracy and low tempco enable ±0.3 V absolute output accuracy without manual calibration - reducing manufacturing test time. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDT | 0.5% initial voltage accuracy (vs. 1%), same SO-8 package and temperature range. | Required where tighter output regulation is needed (e.g., high-precision instrumentation power rails). | Select TL431BIDT if system-level voltage tolerance demands <±0.5% output error without trimming. |
| TLVH431AIDBVR | Lower 1.24 V reference (not 2.5 V), SOT-23-3 package, 1% accuracy, –40 °C to +125 °C. | Used where lower reference voltage enables higher resistor-divider ratios or reduced quiescent current in ultra-low-power systems. | Choose TLVH431AIDBVR only when 1.24 V reference is acceptable and board space constraints favor SOT-23-3. |
Compared with TL431AIDT, TL431BIDT offers higher accuracy at identical thermal and packaging specs, while TLVH431AIDBVR trades reference voltage and package size for wider temperature range and smaller footprint - neither is pin-compatible, requiring schematic and layout revision.
Availability
TL431AIDT is available at Aetrix Electronics and suitable for automotive power supply feedback, industrial isolated DC-DC converters, and battery management systems requiring stable component supply with AEC-Q100 compliance and long-term lifecycle assurance.
Supply support for TL431AIDT 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 microcontrollers, power ICs, sensors, and analog components for automotive, industrial, and consumer markets.
TL431AIDT belongs to ST's precision analog voltage reference product line, engineered specifically for automotive and industrial power conversion systems demanding high reliability, extended temperature operation, and tight initial accuracy.
FAQ
What is the maximum cathode-to-anode voltage rating for TL431AIDT?
The absolute maximum cathode-to-anode voltage (VKA) is 37 V. Operation above this risks permanent damage. The device is rated for continuous operation up to 36 V, making it suitable for 24 V and 36 V automotive and industrial bus applications with appropriate derating.
Can TL431AIDT replace TL431CDT in existing designs?
Yes, TL431AIDT is a direct functional and pin-compatible replacement for TL431CDT, with identical SO-8 package and pinout. However, TL431AIDT extends the operating temperature range from 0–70 °C to –40–105 °C and improves reference accuracy from 2% to 1%, enhancing performance in automotive and industrial environments.
Does TL431AIDT require external compensation for stability?
No external compensation is required for stability with capacitive loads ≤10 µF, as confirmed in ST's datasheet Figure 21. For loads >10 µF or highly reactive feedback networks, a small series resistor (10–100 Ω) between REF and divider may be needed - but standard optocoupler-based SMPS designs operate reliably without added components.
How does the REF pin input current affect accuracy in precision applications?
The REF pin draws ≤4 µA at 25 °C (≤6.5 µA over full temperature range). When using high-value feedback resistors (>100 kΩ), this current introduces voltage division error - e.g., 100 kΩ top resistor yields ~0.4 mV offset. For sub-0.1% accuracy, keep total divider resistance ≤50 kΩ or use a buffered REF input.
TL431AIDT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- 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:
- 700 µA
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TL431AIDT FAQ
1.How can I place an order for TL431AIDT through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431AIDT 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 TL431AIDT reliable?
The price and inventory of TL431AIDT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431AIDT is usually 5 days.
3.What payment methods are accepted for TL431AIDT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431AIDT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431AIDT?
TL431AIDT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431AIDT 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 TL431AIDT?
For technical support, including TL431AIDT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431AIDT requirements.
6.How does Aetrix verify that TL431AIDT is sourced from the original manufacturer or authorized distributors?
All TL431AIDT 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 TL431AIDT meets industry standards.
7.What is the process for return or replacement of TL431AIDT?
All TL431AIDT units undergo pre-shipment inspection (PSI). If there is an issue with TL431AIDT, 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 TL431AIDT part is unused and in its original packaging.
Return procedure for TL431AIDT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431AIDT Tags
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TL431AIDBZR
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TL431BQDBZR
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AN431AN-ATRG1
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LM4040CYM3-2.5-TR
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LM4040CYM3-4.1-TR
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AZ431LBNTR-G1
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LM4040D20IDBZR
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LM4041DIM3-ADJ/NOPB
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LM4040DIM3X-2.5/NOPB
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LM4040DIM3-2.5/NOPB
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AZ431LANTR-G1
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