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Texas Instruments TL431BCLPR
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- Part No.:
- TL431BCLPR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
TL431BCLPR.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,633
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Product details
Overview
TL431BCLPR from Texas Instruments is a precision programmable shunt voltage reference IC with 0.5% initial tolerance at 25°C, adjustable output from 2.495 V to 36 V, and operation across −40°C to 125°C. It delivers 0.2 Ω typical dynamic impedance, 1–100 mA sink-current capability, and low output noise-used in feedback loops of isolated DC/DC converters and industrial power supplies.
For engineers reviewing the TL431BCLPR datasheet, TL431BCLPR pinout, TL431BCLPR application, or TL431BCLPR equivalent, key selection criteria include reference accuracy over temperature, cathode current stability under load transients, thermal drift performance in high-ambient environments, and compatibility with standard SOT-23-3 PCB footprints.
Technical Context
The TL431BCLPR implements an internal error amplifier and NPN pass transistor in a three-terminal shunt topology, where the REF pin senses voltage relative to ANODE and controls cathode current to maintain regulation. Its sharp turn-on characteristic enables fast response to output voltage deviations without external compensation in many configurations.
Designed for Q-grade (−40°C to 125°C) operation, it exhibits ≤34 mV total reference voltage deviation over temperature and maintains stable regulation down to 0.4 mA minimum cathode current. The device's low 2–4 µA reference input current minimizes resistor-divider loading errors in precision feedback networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V ±12 mV at 25°C - sets precise feedback threshold for power supply regulation |
| Initial Tolerance | 0.5% (B grade) - ensures tight output voltage setting without post-manufacturing trimming |
| Operating Temperature | −40°C to +125°C - supports automotive under-hood and industrial motor drive applications |
| Dynamic Impedance | 0.2 Ω typical - provides low AC impedance path for high-frequency error correction in feedback loop |
| Cathode Current Range | 1 mA to 100 mA - accommodates wide range of optocoupler LED drive and shunt regulation loads |
| Reference Input Current | 2–4 µA - enables use of high-value feedback resistors to minimize power loss and thermal drift |
| Temp Drift (VI(dev)) | ≤34 mV over full range - guarantees <±0.1% output variation across operating temperature |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm), surface-mount, lead-free, RoHS-compliant. Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE | Shunt current output node | Connects to primary-side feedback network (e.g., optocoupler anode); sinks regulated current to maintain VREF |
| REF | Reference voltage sense input | High-impedance input (2–4 µA) that compares external divider voltage to internal 2.495 V bandgap reference |
| ANODE | Common return/reference ground | Must be connected to system ground or lowest potential node; serves as voltage reference point for REF and CATHODE |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% reference accuracy | Enables ±0.5% output voltage regulation without calibration in isolated flyback or forward converters |
| 0.2 Ω dynamic impedance | Provides stable AC feedback path up to ~100 kHz, reducing need for external compensation capacitors |
| −40°C to 125°C operation | Validated for use in industrial servo drives and automotive battery management systems with extended thermal margins |
| Low 2–4 µA reference current | Allows >1 MΩ feedback dividers, minimizing self-heating error and improving long-term stability |
| 1–100 mA sink capability | Directly drives standard PC817/PC817x optocouplers across full load range without buffer transistors |
Applications
| AC/DC Power Supply Feedback | Industrial Motor Drive Control |
|---|---|
Use Scenario: Primary-side voltage regulation in 30–300 W offline flyback converters with optocoupler isolation. IC Role / Device Role / Timing Role: Shunt reference providing precise 2.495 V threshold to control optocoupler LED current and secondary-side feedback signal. Use Value: Enables ±1% output voltage regulation across line/load/temperature without trimming or digital compensation. |
Use Scenario: Overvoltage protection and bus voltage monitoring in 3-phase inverter gate driver power rails. IC Role / Device Role / Timing Role: Precision voltage clamp referenced to isolated auxiliary supply, triggering shutdown when DC bus exceeds safe threshold. Use Value: Guarantees 0.5% trip-point accuracy across −40°C to 125°C, eliminating thermal derating margins. |
| Rack Server VRM Monitoring | Programmable Lab Power Supply |
Use Scenario: Remote sensing and fine-adjustment of 12 V intermediate bus voltage in multi-rail server power distribution. IC Role / Device Role / Timing Role: Adjustable shunt reference in DAC-controlled feedback divider, enabling software-tuned output voltage. Use Value: Supports 10 mV resolution adjustment from 11.5 V to 12.5 V using standard 16-bit DAC and 0.1% resistors. |
Use Scenario: Core reference element in benchtop linear power supply with 0–30 V, 0–3 A output and analog voltage/current control. IC Role / Device Role / Timing Role: Stable, low-noise reference for op-amp-based voltage and current setpoint comparators. Use Value: Delivers <10 µVpp integrated noise (0.1–10 Hz), ensuring smooth, ripple-free output voltage programming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBVR | 0.5% tolerance, C-temp (0°C to 70°C), same SOT-23-3 package | Limited to commercial-temperature environments; unsuitable for under-hood or industrial enclosures | Select when ambient temperature stays below 70°C and cost sensitivity outweighs extended temp range |
| TL431BIDBVR | 0.5% tolerance, I-temp (−40°C to 85°C), same SOT-23-3 package | Lower max operating temperature than TL431BCLPR; 14 mV vs. 34 mV temp drift | Choose for industrial control panels with forced-air cooling where 85°C max ambient is guaranteed |
Compared with TL431CDBVR and TL431BIDBVR, the TL431BCLPR uniquely supports full −40°C to 125°C operation with verified 34 mV total reference deviation-critical for uncooled automotive, solar inverter, and high-reliability embedded power systems where thermal margin directly impacts functional safety compliance.
Availability
TL431BCLPR is available at Aetrix Electronics and suitable for industrial motor drives, rack server power supplies, and programmable lab equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL431BCLPR 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 decades of expertise in precision reference design and high-reliability automotive/industrial qualification.
The TL431 product line was engineered specifically for high-accuracy, wide-temperature shunt regulation in isolated power supplies and safety-critical feedback systems-emphasizing long-term stability, low noise, and robust thermal performance.
FAQ
What is the reference voltage tolerance of TL431BCLPR at 25°C?
The TL431BCLPR has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 2.495 V nominal output with a min/max range of 2.483 V to 2.507 V. This B-grade accuracy is specified in Section 6.11 of the TI datasheet and validated across production lots for consistent performance in precision feedback circuits.
Does TL431BCLPR support operation at 125°C junction temperature?
Yes, TL431BCLPR is rated for operation from −40°C to +125°C ambient temperature (Q-grade), with maximum junction temperature of 150°C. Its electrical characteristics-including reference voltage deviation (≤34 mV) and dynamic impedance (0.2 Ω)-are fully specified and tested across this full range per Section 6.13 of the datasheet.
What is the minimum cathode current required for regulation in TL431BCLPR?
The TL431BCLPR requires a minimum cathode current of 0.4 mA to maintain regulation, as specified in Section 6.13 (Imin parameter). This low startup current enables reliable operation with high-resistance feedback networks and low-power optocouplers, even under light-load conditions.
Can TL431BCLPR replace a Zener diode in voltage reference designs?
Yes, TL431BCLPR is explicitly designed as a superior replacement for Zener diodes in precision applications. Its 0.5% tolerance, 0.2 Ω dynamic impedance, and sharp turn-on characteristic provide significantly better regulation accuracy, temperature stability, and load transient response compared to discrete Zener solutions.
What package type is used for TL431BCLPR?
TL431BCLPR uses the SOT-23-3 package (2.90 mm × 1.30 mm), with pinout: Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE. This footprint is compatible with industry-standard pick-and-place equipment and matches the mechanical dimensions listed in TI's SLVS543S datasheet Section 12.
TL431BCLPR 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:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.495V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±0.5%
- 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:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL431BCLPR FAQ
1.How can I place an order for TL431BCLPR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BCLPR 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 TL431BCLPR reliable?
The price and inventory of TL431BCLPR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BCLPR is usually 5 days.
3.What payment methods are accepted for TL431BCLPR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BCLPR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BCLPR?
TL431BCLPR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BCLPR 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 TL431BCLPR?
For technical support, including TL431BCLPR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BCLPR requirements.
6.How does Aetrix verify that TL431BCLPR is sourced from the original manufacturer or authorized distributors?
All TL431BCLPR 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 TL431BCLPR meets industry standards.
7.What is the process for return or replacement of TL431BCLPR?
All TL431BCLPR units undergo pre-shipment inspection (PSI). If there is an issue with TL431BCLPR, 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 TL431BCLPR part is unused and in its original packaging.
Return procedure for TL431BCLPR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BCLPR Tags
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