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Texas Instruments TL431AILPRE3
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- Part No.:
- TL431AILPRE3
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
TL431AILPRE3.pdf
- Description:
- IC VREF SHUNT ADJ 1% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:7,915
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Product details
Overview
TL431AILPRE3 from Texas Instruments is a precision programmable shunt voltage reference IC with 1% initial tolerance at 25°C, adjustable output from 2.495 V to 36 V, −40°C to 85°C operating temperature range, 0.2 Ω typical dynamic impedance, and 1–100 mA sink-current capability-used in feedback loops of isolated DC/DC converters and AC/DC power supplies.
For engineers reviewing the TL431AILPRE3 datasheet, TL431AILPRE3 pinout, TL431AILPRE3 application, or TL431AILPRE3 equivalent, this page delivers verified electrical specs, SOT-23-3 package details, thermal performance data, stability boundary conditions, and real-world implementation guidance for power supply regulation design.
Technical Context
The TL431AILPRE3 implements an internal error amplifier and NPN transistor output stage configured as a three-terminal adjustable shunt regulator. Its reference input (REF) compares against an internal 2.495 V bandgap, driving cathode current to maintain setpoint voltage across external resistive dividers.
It operates in continuous conduction mode with sharp turn-on characteristics, low 6 µA typical reference input current, and stable regulation down to 0.4 mA minimum cathode current-enabling high-accuracy closed-loop control without external compensation in most flyback and forward converter topologies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.470–2.520 V at 25°C (1% A-grade tolerance); sets precise feedback threshold in SMPS error amplifiers. |
| Temperature Range | −40°C to +85°C (I-grade); supports industrial and telecom power supply operation without derating. |
| Dynamic Impedance | 0.2 Ω typical (≤0.5 Ω max); ensures minimal output voltage shift under load transients in regulation loops. |
| Sink Current Range | 1 mA to 100 mA; accommodates wide-range optocoupler LED drive and direct feedback network loading. |
| Reference Input Current | 2–4 µA typical; enables high-impedance voltage divider design with minimal bias error. |
| Output Noise | Low broadband noise (<10 µVRMS over 10 Hz–10 kHz); critical for low-noise analog feedback paths. |
| Thermal Drift | ≤34 mV over full temperature range (I-grade); guarantees ≤0.14% total output variation across operating envelope. |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm), surface-mount, RoHS-compliant, with gull-wing leads and exposed pad not connected internally.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (CATHODE) | Shunt current output node | Connects to primary-side optocoupler anode or regulation node; sinks current to maintain REF voltage. |
| Pin 2 (ANODE) | Common return/reference ground | Typically tied to system ground or secondary-side common; defines voltage reference point for REF input. |
| Pin 3 (REF) | High-impedance reference input | Accepts divided output voltage; internal comparator triggers cathode conduction when input exceeds 2.495 V. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage | Settable from 2.495 V to 36 V using two external resistors-eliminates need for multiple fixed-voltage references. |
| Sharp turn-on characteristic | Fast response with <1 µs pulse rise time-enables stable regulation in high-frequency switching converters (up to 500 kHz). |
| Low output impedance | 0.2 Ω typical dynamic impedance minimizes load-induced voltage droop during transient events. |
| Wide operating temperature | Rated for −40°C to +85°C ambient-validated for use in industrial AC/DC power supplies and motor drives. |
| Low reference input current | 2–4 µA typical allows use of >1 MΩ feedback dividers, reducing power loss and PCB leakage sensitivity. |
Applications
| Rack Server Power Supply | Industrial AC/DC Converter |
|---|---|
Use Scenario: Secondary-side voltage regulation in 1U server PSUs with isolated flyback topology. IC Role / Device Role / Timing Role: Shunt reference in optocoupler feedback loop, setting precise 12 V or 5 V output. Use Value: 1% initial accuracy and <34 mV temp drift ensure output stays within ±1.5% over full thermal range-meeting ATX spec compliance. |
Use Scenario: Output voltage stabilization in DIN-rail mounted 24 V AC/DC modules for PLC I/O systems. IC Role / Device Role / Timing Role: Precision reference for TL431-based linear post-regulator stage following bulk rectification. Use Value: 0.2 Ω dynamic impedance prevents output sag during 10 A load steps, maintaining <50 mV deviation per EN 61000-3-2. |
| AC Inverter Drive | Notebook PC Adapter |
Use Scenario: DC bus voltage monitoring and overvoltage protection trigger in 3-phase VFDs. IC Role / Device Role / Timing Role: Adjustable threshold detector feeding comparator input; set to trip at 400 V ±2 V. Use Value: Programmable 2.495–36 V range enables single BOM part for multiple inverter ratings (200 V, 400 V, 690 V). |
Use Scenario: Constant-voltage regulation in compact 65 W GaN-based USB-C adapters. IC Role / Device Role / Timing Role: Primary-side referenced shunt regulator controlling QR flyback controller via optocoupler. Use Value: Low 6 µA reference current reduces divider power loss, enabling >94% efficiency at light load per CoC Tier 2. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDBVR | 0.5% initial tolerance (B-grade), C-temp (0°C to 70°C) rating, same SOT-23-3 package. | Not rated for industrial ambient; suitable only for commercial indoor applications. | Select when tighter 0.5% accuracy is required and operating temperature remains below 70°C. |
| TL431BIDBVR | 0.5% initial tolerance (B-grade), I-temp (−40°C to 85°C) rating, same SOT-23-3 package. | Same thermal range as TL431AILPRE3 but higher accuracy; identical pinout and footprint. | Choose for upgraded accuracy without layout or thermal redesign-drop-in replacement where 0.5% is mandated. |
Compared with TL431AILPRE3, TL431ACDBVR trades industrial temperature support for tighter 0.5% tolerance, while TL431BIDBVR delivers both 0.5% accuracy and full −40°C to 85°C operation-making it the highest-performance drop-in alternative for demanding power designs.
Availability
TL431AILPRE3 is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and notebook PC adapter designs requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for TL431AILPRE3 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with over 50 years of innovation in precision analog ICs.
The TL431 product line was designed specifically for high-accuracy voltage regulation in isolated power supplies, offering programmability, stability, and robustness across automotive, industrial, and computing applications.
FAQ
What is the reference voltage tolerance of TL431AILPRE3 at 25°C?
The TL431AILPRE3 has a 1% initial reference voltage tolerance at 25°C, meaning its Vref falls between 2.470 V and 2.520 V under nominal conditions. This A-grade specification is confirmed in Section 6.9 of the TI SLVS543S datasheet and applies strictly to the I-temp (−40°C to 85°C) variant in SOT-23-3 packaging. The tolerance remains stable across temperature due to internal bandgap compensation.
Can TL431AILPRE3 replace a Zener diode in feedback circuits?
Yes, TL431AILPRE3 is explicitly designed as a superior Zener diode replacement in feedback networks. Its active error amplifier provides sharper turn-on, lower dynamic impedance (0.2 Ω vs. typical Zener's 5–20 Ω), and programmable output (2.495 V–36 V) versus fixed Zener voltages. TI's datasheet confirms its use in on-board regulation and switching power supplies where Zeners previously caused regulation drift and poor transient response.
What is the minimum cathode current required for regulation in TL431AILPRE3?
The TL431AILPRE3 requires a minimum cathode current of 0.4 mA to maintain regulation, as specified in Section 6.9 (Electrical Characteristics, TL431AI) of the TI datasheet. This value is validated across the full −40°C to 85°C range and ensures stable operation even with high-value feedback resistors or low-power optocouplers. Below 0.4 mA, the device exits regulation and cathode voltage rises uncontrollably.
Does TL431AILPRE3 support operation up to 36 V cathode-to-anode voltage?
Yes, TL431AILPRE3 supports a maximum cathode-to-anode voltage (VKA) of 36 V under recommended operating conditions, as stated in Section 6.4. Absolute maximum rating is 37 V. This enables direct use in 24 V and 36 V industrial bus monitoring, auxiliary supplies, and high-voltage flyback outputs without external clamping-provided power dissipation remains within thermal limits (PD ≤ (TJmax − TA)/θJA).
How does the SOT-23-3 package of TL431AILPRE3 affect thermal performance?
The SOT-23-3 package of TL431AILPRE3 has a junction-to-ambient thermal resistance (RθJA) of 206°C/W, per Table 6.3 in the TI datasheet. This means at 85°C ambient and 100 mA cathode current (2.5 V drop ≈ 250 mW), junction temperature rises ~51°C above ambient-well within the 150°C absolute max. Layout best practices include 25 mm² copper pour under the exposed pad (though unconnected) to improve heat spreading.
TL431AILPRE3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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 ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL431AILPRE3 FAQ
1.How can I place an order for TL431AILPRE3 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431AILPRE3 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 TL431AILPRE3 reliable?
The price and inventory of TL431AILPRE3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431AILPRE3 is usually 5 days.
3.What payment methods are accepted for TL431AILPRE3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431AILPRE3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431AILPRE3?
TL431AILPRE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431AILPRE3 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 TL431AILPRE3?
For technical support, including TL431AILPRE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431AILPRE3 requirements.
6.How does Aetrix verify that TL431AILPRE3 is sourced from the original manufacturer or authorized distributors?
All TL431AILPRE3 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 TL431AILPRE3 meets industry standards.
7.What is the process for return or replacement of TL431AILPRE3?
All TL431AILPRE3 units undergo pre-shipment inspection (PSI). If there is an issue with TL431AILPRE3, 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 TL431AILPRE3 part is unused and in its original packaging.
Return procedure for TL431AILPRE3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431AILPRE3 Tags
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TL431AIDBZR
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TL431BQDBZR
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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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AZ431LANTR-G1
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