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Texas Instruments TL431BQDCKT
- Part No.:
- TL431BQDCKT
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 6-TSSOP, SC-88, SOT-363
- Datasheet:
-
TL431BQDCKT.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SC70-6
- Quantity:
- Payment:
- Shipping:
Inventory:5,070
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Product details
Overview
TL431BQDCKT from Texas Instruments is a precision programmable shunt voltage reference in SOT-23-3 package, featuring 0.5% initial reference voltage tolerance at 25°C, −40°C to +125°C operating temperature range, and 0.2 Ω typical dynamic impedance. It delivers stable 2.495 V reference output adjustable up to 36 V via external resistors and supports sink-current capability from 1 mA to 100 mA - widely used in isolated feedback loops of AC/DC adapters and industrial power supplies.
For engineers reviewing the TL431BQDCKT datasheet, TL431BQDCKT pinout, TL431BQDCKT application, or TL431BQDCKT equivalent, this page provides verified electrical specifications, thermal performance data, pin-level functional roles, automotive-grade temperature stability metrics, and real-world implementation guidance for closed-loop regulation design.
Technical Context
The TL431BQDCKT implements a three-terminal adjustable shunt regulator architecture with an internal error amplifier, reference voltage source, and output transistor. Its Q-grade rating confirms characterization across −40°C to +125°C, enabling use in under-hood automotive and industrial environments where thermal drift must remain within ±14 mV over full temperature range.
It operates as a precision voltage comparator driving a high-gain NPN output stage, sinking cathode current proportional to the difference between REF pin voltage and internal 2.495 V bandgap reference. The device requires no external compensation in most configurations but exhibits defined stability boundaries dependent on load capacitance and cathode voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VREF) | 2.495 V nominal (2.483–2.507 V min/max), enabling accurate feedback setpoint for isolated DC-DC converters |
| Initial Tolerance | ±0.5% at 25°C (B grade), reducing output voltage calibration burden in production test |
| Temp Range | −40°C to +125°C (Q grade), qualified for automotive engine control and industrial motor drive applications |
| Dynamic Impedance | 0.2 Ω typical, ensuring minimal output voltage shift under fast load transients in regulation circuits |
| Cathode Current Range | 1 mA to 100 mA sink capability, supporting direct interface with optocoupler LEDs in flyback feedback paths |
| Ref Input Current | 2–4 µA typical, allowing high-value resistor dividers (>1 MΩ) without significant divider error |
| Temp Drift (VIdev) | ≤34 mV over full −40°C to +125°C range, meeting tight stability requirements in servo power stages |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm body size), surface-mount, lead-free, RoHS-compliant. Pin 1 = Cathode, Pin 2 = Anode, Pin 3 = Reference (REF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 1) | Shunt current output node | Connects to primary-side optocoupler LED or series-pass transistor base; sinks regulated current to maintain VREF at 2.495 V |
| Anode (Pin 2) | Common return/reference ground | Typically tied to system ground or secondary-side return; defines voltage reference point for REF pin measurement |
| REF (Pin 3) | Feedback input threshold | Compares external resistor-divider voltage against internal 2.495 V reference; triggers cathode conduction when input exceeds threshold |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% initial accuracy | Reduces need for post-manufacturing trimming in power supply feedback networks |
| 0.2 Ω dynamic impedance | Maintains <±1 mV output variation during 10–100 mA cathode current steps, critical for tight regulation |
| −40°C to +125°C operation | Enables deployment in automotive under-hood modules and industrial PLC power rails without derating |
| Low 2–4 µA reference current | Permits use of >1 MΩ resistor dividers, minimizing standby power loss in battery-backed systems |
| Stable with ≤100 pF capacitive load | Eliminates need for external compensation in most optocoupler-coupled SMPS feedback designs |
Applications
| AC/DC Power Adapter | Rack Server PSU |
|---|---|
|
Use Scenario: Secondary-side voltage sensing in isolated flyback converter for notebook adapter. IC Role / Device Role / Timing Role: Precision shunt reference providing feedback signal to optocoupler LED driver. Use Value: Enables ±1% output voltage regulation across line/load/temperature with no secondary-side LDO. |
Use Scenario: Output voltage monitoring and regulation in multi-rail 12 V/5 V/3.3 V server power supply. IC Role / Device Role / Timing Role: Programmable reference for digital PWM controller feedback loop. Use Value: Supports dynamic voltage scaling and margining via resistor network reconfiguration without hardware change. |
| Industrial Motor Drive | Automotive Body Control Module |
|
Use Scenario: DC bus voltage sensing and overvoltage protection in VF inverter drives. IC Role / Device Role / Timing Role: High-stability reference for comparator-based fault detection circuit. Use Value: Maintains trip threshold accuracy within ±15 mV over −40°C to +125°C, preventing false shutdowns. |
Use Scenario: Regulated 5 V rail generation for microcontroller and CAN transceiver in BCM. IC Role / Device Role / Timing Role: Shunt reference in linear regulator feedback path for low-noise analog supply. Use Value: Delivers <10 µVRMS noise contribution and <0.5% output tolerance, meeting ASIL-B analog integrity requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBZR | SOT-23-3, same B-grade accuracy and Q-temp rating, but TI's alternate packaging code (DBZR vs DCKT); identical electrical specs. | No functional difference; validated for same automotive and industrial feedback designs. | Select TL431BIDBZR only if preferred distributor stock or tape-and-reel format differs. |
| ON Semiconductor NCP1002DR2G | 0.5% initial tolerance, −40°C to +125°C, but higher 0.5 Ω dynamic impedance and 5 µA reference current. | Acceptable for less demanding regulation tasks; may require larger feedback resistors or tighter layout to maintain stability. | Choose only when TL431BQDCKT is unavailable; verify loop stability with actual PCB parasitics before qualification. |
Compared with TL431BQDCKT, TL431BIDBZR offers identical performance and drop-in compatibility, while NCP1002DR2G trades higher impedance and input current for second-source availability - making TL431BQDCKT optimal for high-precision, low-noise, and thermally aggressive applications.
Availability
TL431BQDCKT is available at Aetrix Electronics and suitable for AC/DC power adapters, rack server PSUs, and industrial motor drives requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL431BQDCKT 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 company specializing in analog and embedded processing technologies, with leadership in power management and precision analog ICs.
The TL431 product line was designed for high-accuracy, wide-temperature shunt regulation in isolated power supplies, industrial controls, and automotive systems - delivering Zener-diode replacement performance with programmability and stability.
FAQ
What is the reference voltage tolerance of TL431BQDCKT at 25°C?
The TL431BQDCKT has a guaranteed initial reference voltage tolerance of ±0.5% at 25°C, corresponding to a 2.483 V to 2.507 V range around the nominal 2.495 V output. This B-grade specification is explicitly confirmed in Section 6.13 of the TI SLVS543S datasheet and applies specifically to the TL431BQ variant in SOT-23-3 packaging. TL431BQDCKT maintains this accuracy without trimming.
Does TL431BQDCKT support operation at 125°C ambient temperature?
Yes, TL431BQDCKT is rated for continuous operation from −40°C to +125°C (Q-grade), with all electrical characteristics fully specified across that range. Its VI(dev) parameter is limited to ≤34 mV over this interval, and thermal resistance RθJA is 206°C/W in the SOT-23-3 (DCK) package - enabling reliable use in under-hood automotive modules and industrial inverters without derating.
What is the minimum cathode current required for regulation in TL431BQDCKT?
The TL431BQDCKT requires a minimum cathode current of 0.4 mA to maintain regulation, as specified in Section 6.13 (Electrical Characteristics, TL431BQ/TL432BQ). This value ensures stable reference behavior even at light loads, such as when driving high-impedance optocoupler inputs or high-value feedback dividers in low-power standby modes.
Can TL431BQDCKT replace a standard Zener diode in feedback circuits?
Yes, TL431BQDCKT is explicitly designed as a precision Zener diode replacement, offering programmable output (2.495 V to 36 V), lower dynamic impedance (0.2 Ω vs typical Zener >10 Ω), tighter tolerance (±0.5%), and superior temperature stability. Its three-terminal configuration enables active feedback control unattainable with passive Zeners - making TL431BQDCKT ideal for modern switching power supply regulation.
What is the dynamic impedance of TL431BQDCKT and why does it matter?
The TL431BQDCKT has a typical dynamic impedance of 0.2 Ω, measured at 1 kHz with cathode current between 1 mA and 100 mA. This low value means the output voltage changes by only ~0.2 mV per 1 mA load step - critical for maintaining tight regulation during transient events in power supplies. It directly improves load regulation performance compared to discrete Zener solutions.
TL431BQDCKT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 6-TSSOP, SC-88, SOT-363
- 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:
- 700 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-6
TL431BQDCKT FAQ
1.How can I place an order for TL431BQDCKT through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BQDCKT 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 TL431BQDCKT reliable?
The price and inventory of TL431BQDCKT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BQDCKT is usually 5 days.
3.What payment methods are accepted for TL431BQDCKT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BQDCKT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BQDCKT?
TL431BQDCKT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BQDCKT 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 TL431BQDCKT?
For technical support, including TL431BQDCKT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BQDCKT requirements.
6.How does Aetrix verify that TL431BQDCKT is sourced from the original manufacturer or authorized distributors?
All TL431BQDCKT 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 TL431BQDCKT meets industry standards.
7.What is the process for return or replacement of TL431BQDCKT?
All TL431BQDCKT units undergo pre-shipment inspection (PSI). If there is an issue with TL431BQDCKT, 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 TL431BQDCKT part is unused and in its original packaging.
Return procedure for TL431BQDCKT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BQDCKT Tags
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