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STMicroelectronics TL431ACDT
- Part No.:
- TL431ACDT
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431ACDT.pdf
- Description:
- IC VREF SHUNT ADJ 1% 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:28,283
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Product details
Overview
TL431ACDT from STMicroelectronics is an AEC-Q100 qualified adjustable shunt voltage reference IC operating as a precision 2.5 V reference with programmable output up to 36 V via external resistors, delivering 1–100 mA sink current, 0.22 Ω typical dynamic impedance, and 1% initial voltage accuracy across –40 °C to +125 °C - used in automotive power supply feedback loops and industrial voltage regulation circuits.
For engineers reviewing the TL431ACDT datasheet, TL431ACDT pinout, TL431ACDT application, or TL431ACDT equivalent, this page delivers verified technical context, SO-8 package mapping, automotive-grade thermal stability data, and real-world design value for closed-loop voltage control in safety-critical systems.
Technical Context
The TL431ACDT implements a three-terminal adjustable shunt regulator architecture where the REF pin senses a divided cathode voltage, triggering internal error amplification to modulate cathode-to-anode conduction. Its operation requires ≥0.5 mA minimum cathode current for regulation and supports stable feedback across 1–100 mA load range.
It features a 2.5 V bandgap-based reference core with <±7 mV temperature-induced deviation over –40 °C to +125 °C, 0.22 Ω dynamic impedance at 1 kHz, and <6.5 µA reference input current - enabling high-precision, low-drift voltage setpoints without external compensation in flyback, buck, or linear regulator topologies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.5 V ±1% (2.45–2.55 V) at 25 °C - sets accurate feedback threshold for power supply error amplifiers |
| Output Voltage Range | 2.5 to 36 V via two external resistors - enables flexible regulation across 12 V, 24 V, and 48 V automotive/industrial rails |
| Sink Current Capability | 1 to 100 mA - supports direct drive of optocoupler LEDs or error amplifier inputs without buffering |
| Dynamic Impedance | 0.22 Ω typical at ≤1 kHz - ensures minimal output voltage perturbation under transient load steps |
| Temp. Range | –40 °C to +125 °C - validated for under-hood automotive environments and industrial control cabinets |
| Voltage Deviation | ±7 mV over full temperature range - guarantees <0.3% total variation in reference accuracy across operating conditions |
| Ref Input Current | ≤4 µA typical at 25 °C - minimizes resistor-divider loading error and enables high-impedance feedback networks |
Pinout & Package
TL431ACDT is supplied in an SO-8 "batwing" plastic micropackage (ECOPACK® compliant), offering enhanced thermal dissipation (RthJA = 85 °C/W) and mechanical robustness for automotive PCB mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Anode) | Anode terminal | Connects to system ground or low-side return path; sinks current when device is active |
| 2 (Cathode) | Cathode terminal | High-side output node; connects to power rail or optocoupler anode; carries full regulated sink current |
| 3 (REF) | Reference input | Senses voltage divider output; triggers regulation when ≈2.5 V applied; draws ≤4 µA |
| 4 (NC) | No connect | Internally unconnected; must remain floating or tied to ground per layout best practices |
| 5 (NC) | No connect | Internally unconnected; no electrical function; avoid routing signals nearby |
| 6 (NC) | No connect | Internally unconnected; unused pin; maintain clearance for thermal and EMI integrity |
| 7 (NC) | No connect | Internally unconnected; not bonded; leave unconnected on PCB |
| 8 (NC) | No connect | Internally unconnected; no bond wire; do not tie to any net |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualification | Validated for automotive applications including engine control units and ADAS power supplies |
| 1% initial voltage accuracy | Reduces need for post-manufacturing calibration in production power modules |
| 0.22 Ω dynamic impedance | Enables fast transient response in isolated DC-DC feedback paths without added compensation |
| –40 °C to +125 °C operation | Supports placement near heat-generating components in compact automotive ECUs |
| SO-8 batwing package | Provides superior thermal performance vs. TO-92 or SOT-23 variants for sustained 100 mA operation |
Applications
| Automotive Power Supply Feedback | Industrial Isolated DC-DC Regulation |
|---|---|
Use Scenario: Closed-loop voltage sensing in 12 V/24 V automotive buck converters feeding infotainment and body control modules. IC Role / Device Role / Timing Role: Shunt reference providing precise 2.5 V threshold to error amplifier; regulates output by adjusting optocoupler LED current. Use Value: Maintains ±1% output tolerance across temperature and line variations, meeting ISO 16750-2 load dump requirements. |
Use Scenario: Secondary-side voltage monitoring in 48 V telecom DC-DC converters with transformer isolation. IC Role / Device Role / Timing Role: Precision reference driving optocoupler input to transmit feedback across isolation barrier; replaces discrete Zener + op-amp solutions. Use Value: Eliminates 3–5 component BOM cost while achieving <10 µs response time to output transients. |
| Programmable Overvoltage Protection | Adjustable Linear Regulator Reference |
Use Scenario: Threshold detection in battery management systems for Li-ion pack overvoltage cutoff at 4.3 V/cell. IC Role / Device Role / Timing Role: Programmable shunt clamp activated when divided cell voltage exceeds setpoint; sinks fault current to trigger shutdown logic. Use Value: Achieves ±0.01 V trip accuracy over –40 °C to +85 °C without trimming, reducing test time and calibration cost. |
Use Scenario: Output voltage setting in low-noise LDO regulators for analog sensor signal chains in factory automation PLCs. IC Role / Device Role / Timing Role: External reference source replacing internal bandgap; improves PSRR and thermal drift performance of LDO error amplifier. Use Value: Low 0.22 Ω impedance prevents reference droop during 50 mA load steps, preserving ADC reference stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACD | Same electrical specs but in tube packaging (not tape-and-reel); identical SO-8 footprint and pinout | Preferred for low-volume prototyping or manual assembly where reel handling is unnecessary | Select TL431ACD for lab evaluation; TL431ACDT for automated SMT production with pick-and-place feeders |
| TL431BIDT | 0.5% initial accuracy (vs. 1%), same SO-8 package, –40 °C to +125 °C rating, higher cost | Used where tighter reference tolerance is required for high-accuracy measurement subsystems | Choose TL431BIDT only if system-level calibration budget demands <0.5% reference contribution |
Compared with TL431ACDT, TL431ACD offers identical performance in non-reel form for bench use, while TL431BIDT trades higher cost for halved voltage error - making TL431ACDT the optimal balance of automotive qualification, 1% accuracy, and tape-and-reel manufacturability.
Availability
TL431ACDT is available at Aetrix Electronics and suitable for automotive power supply feedback, industrial isolated DC-DC regulation, and programmable overvoltage protection requiring stable component supply across extended temperature ranges.
Supply support for TL431ACDT 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.
The TL431 product line delivers precision programmable shunt references optimized for closed-loop voltage regulation in safety-critical automotive and high-reliability industrial power systems.
FAQ
What is the minimum cathode current required for regulation in TL431ACDT?
The TL431ACDT requires a minimum cathode current of 0.5 mA to maintain regulation, as specified in Table 3 of the STMicroelectronics datasheet (DocID4467 Rev 17). Below this threshold, the device exits regulation mode and output voltage becomes undefined. This value is confirmed across –40 °C to +125 °C ambient temperature.
Can TL431ACDT replace TL431CDT in existing designs?
Yes - TL431ACDT is a direct functional and pin-compatible upgrade to TL431CDT, offering improved 1% initial voltage accuracy (vs. 2%) and identical SO-8 packaging, thermal characteristics, and electrical behavior. No circuit changes are needed; only firmware or calibration adjustments may benefit from tighter tolerance.
Does TL431ACDT require external compensation for stability?
No external compensation is required for basic shunt regulator operation. The device exhibits inherent stability with capacitive loads up to 10 nF, as shown in Figure 21 of the datasheet. For >10 nF loads or high-frequency feedback loops, a series resistor (typically 10–100 Ω) between REF and divider is recommended to damp oscillation.
How does the SO-8 batwing package improve thermal performance over TO-92?
The SO-8 batwing package reduces junction-to-ambient thermal resistance to 85 °C/W versus 200 °C/W for TO-92, enabling continuous 100 mA sink current at +125 °C ambient without derating. Its exposed pad variant (not used in TL431ACDT) further lowers RthJA, but standard SO-8 already supports full-spec operation in compact automotive layouts.
TL431ACDT 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:
- 600 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TL431ACDT FAQ
1.How can I place an order for TL431ACDT through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431ACDT 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 TL431ACDT reliable?
The price and inventory of TL431ACDT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431ACDT is usually 5 days.
3.What payment methods are accepted for TL431ACDT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431ACDT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431ACDT?
TL431ACDT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431ACDT 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 TL431ACDT?
For technical support, including TL431ACDT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431ACDT requirements.
6.How does Aetrix verify that TL431ACDT is sourced from the original manufacturer or authorized distributors?
All TL431ACDT 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 TL431ACDT meets industry standards.
7.What is the process for return or replacement of TL431ACDT?
All TL431ACDT units undergo pre-shipment inspection (PSI). If there is an issue with TL431ACDT, 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 TL431ACDT part is unused and in its original packaging.
Return procedure for TL431ACDT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431ACDT Tags
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TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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AN431AN-ATRG1
Diodes Incorporated
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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
-
LM4040DIM3X-2.5/NOPB
Texas Instruments
-
LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
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