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Texas Instruments TL431LIACDBZR
- Part No.:
- TL431LIACDBZR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431LIACDBZR.pdf
- Description:
- IC VREF SHUNT ADJ 1% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:10,508
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Product details
Overview
TL431LIACDBZR from Texas Instruments is a three-terminal adjustable shunt regulator with 0.5% reference voltage tolerance at 25°C, 2.495 V nominal reference voltage, and sink-current capability up to 15 mA. It operates across −40°C to +125°C (Q-temp grade), features 0.3 Ω typical dynamic impedance, and serves as a precision voltage reference or error amplifier in feedback loops for flyback SMPS secondary-side regulation.
For engineers reviewing the TL431LIACDBZR datasheet, TL431LIACDBZR pinout, TL431LIACDBZR application, or TL431LIACDBZR equivalent, key selection considerations include initial Vref accuracy (0.5%), temperature drift (10 mV over −40°C to +125°C), cathode current range (1–15 mA), reference input current (≤0.4 µA), and SOT-23 (DBZ) package compatibility with space-constrained power management designs.
Technical Context
The TL431LIACDBZR integrates an accurate 2.495 V bandgap reference and high-gain op-amp in a single silicon die, enabling precise shunt regulation via external resistor feedback between cathode and reference pins. Its Darlington output stage delivers 15 mA sink current while maintaining low dynamic impedance (0.3 Ω) and sharp turn-on characteristics.
It supports both open-loop comparator operation (with integrated reference) and closed-loop error amplification, requiring ≥1 mA cathode current for regulation. The device is internally compensated and stable without an output capacitor, though Figure 12 in the datasheet defines stability boundaries when CL is added.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Vref tolerance @ 25°C | ±0.5% (B-grade), enabling ±12.5 mV absolute error at 2.495 V for high-accuracy voltage setting |
| Reference voltage | 2.495 V typical, adjustable from 2.495 V to 36 V using two external resistors |
| Temp drift (−40°C to +125°C) | 10 mV max (Q-temp), ensuring ≤0.4% full-range deviation for stable regulation in automotive/industrial environments |
| IKA range | 1 mA to 15 mA continuous, defining minimum bias and maximum shunt current capability |
| IREF (max) | 0.4 µA, minimizing resistor-divider loading error in precision feedback networks |
| Dynamic impedance | 0.3 Ω typical, limiting output voltage variation to <0.5 mV per 1 mA load step |
| Package | SOT-23 (DBZ), 2.90 mm × 1.30 mm footprint compatible with automated PCB assembly |
Pinout & Package
TL431LIACDBZR uses the DBZ package: 3-pin SOT-23 with 2.90 mm × 1.30 mm body size and standard lead pitch. Pin 1 is CATHODE, Pin 2 is REF, Pin 3 is ANODE - matching TL431 (not TL432) pinout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current output / voltage sensing node | Connects to regulated rail; sinks current to maintain VKA = Vref × (1 + R1/R2); must be biased ≥1 mA for regulation |
| REF (Pin 2) | Reference input / feedback sense point | High-impedance node (IREF ≤ 0.4 µA); tied to voltage divider midpoint to compare against internal 2.495 V reference |
| ANODE (Pin 3) | Common return / ground reference | Typically connected to system ground; all voltages referenced to this pin; forms return path for cathode current |
Key Features
| Feature | Design Value |
|---|---|
| Optimized reference input current | IREF ≤ 0.4 µA (max) reduces resistor-divider error and enables higher-value feedback resistors for lower power loss |
| Low temperature drift | 10 mV max over −40°C to +125°C ensures stable setpoint in automotive under-hood and industrial control applications |
| Sharp turn-on characteristic | Enables clean switching behavior in comparator mode and fast transient response in regulation loops |
| Internal compensation | Stable operation without external output capacitor simplifies layout and reduces BOM count in space-limited designs |
| Pin-to-pin replacement for TL431 | Direct drop-in for legacy TL431 designs with improved IREF and II(dev) specs, no PCB changes required |
Applications
| Secondary-Side Regulation | Zener Diode Replacement |
|---|---|
Use Scenario: Isolated flyback converter where optocoupler feedback references TL431LIACDBZR on secondary side to regulate primary-side PWM controller. IC Role / Device Role / Timing Role: Precision shunt regulator providing error signal to optocoupler LED, enabling tight output voltage regulation (<±1%) across line/load/temperature. Use Value: Replaces discrete Zener + transistor with single IC achieving 0.5% initial accuracy and 10 mV temp drift, improving cross-regulation and reducing component count. | Use Scenario: On-board 3.3 V or 5 V rail stabilization where traditional Zener diodes lack accuracy and thermal stability. IC Role / Device Role / Timing Role: Adjustable shunt reference replacing fixed-voltage Zener, configured via resistive divider to match exact system voltage requirements. Use Value: Delivers 2.495 V reference with ±0.5% tolerance and 0.3 Ω dynamic impedance-reducing output ripple by >10× versus 5% Zener diodes. |
| Voltage Monitoring | Precision Constant Current Sink |
Use Scenario: Microcontroller supply monitoring circuit detecting brown-out conditions before reset assertion. IC Role / Device Role / Timing Role: Comparator with integrated 2.495 V reference comparing monitored rail to trip threshold; open-collector cathode drives MCU interrupt pin. Use Value: Eliminates external reference IC and comparator; 0.4 µA IREF enables high-impedance sensing with minimal loading on monitored rail. | Use Scenario: LED driver or sensor bias circuit requiring stable 100 mA current independent of supply variation. IC Role / Device Role / Timing Role: Error amplifier controlling external pass transistor (e.g., PNP BJT) to force sense-resistor voltage equal to 2.495 V. Use Value: Achieves current accuracy determined by TL431LIACDBZR's 0.5% Vref and sense resistor tolerance-superior to discrete op-amp solutions with external references. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBZR | 1% initial Vref tolerance (A-grade), 27 mV temp drift (C-temp: 0°C to 70°C), higher IREF (1 µA max) | Lower accuracy and narrower temperature range; suitable for commercial-grade non-critical supplies | Select when cost sensitivity outweighs precision and extended temperature needs |
| TLVH431IDBVR | Adjustable down to 1.24 V, 0.5% tolerance, but rated only to 85°C (I-temp) and 10 mA IKA max | Enables lower-voltage regulation but lacks Q-temp rating and 15 mA sink capability | Choose for low-voltage rails (<2.5 V) where 125°C operation is not required |
Compared with TL431CDBZR, TL431LIACDBZR offers tighter Vref tolerance and wider temperature range at similar cost; versus TLVH431IDBVR, it trades lower minimum voltage for higher temperature rating and greater sink current-making TL431LIACDBZR optimal for automotive and industrial 3.3 V/5 V/12 V regulation.
Availability
TL431LIACDBZR is available at Aetrix Electronics and suitable for flyback SMPS secondary-side regulation, precision voltage monitoring, and Zener diode replacement applications requiring stable component supply, long-term lifecycle support, and automotive-grade temperature performance.
Supply support for TL431LIACDBZR 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 designing analog ICs, embedded processors, and digital signal processors for industrial, automotive, and consumer applications.
The TL431LIACDBZR belongs to TI's precision shunt regulator product line, engineered for high-accuracy voltage referencing and error amplification in isolated power supplies, battery management, and safety-critical monitoring systems.
FAQ
What is the reference voltage tolerance of TL431LIACDBZR at 25°C?
The TL431LIACDBZR has a reference voltage tolerance of ±0.5% at 25°C (B-grade specification), corresponding to a 2.495 V nominal Vref with ±12.5 mV absolute error. This tolerance is confirmed in Section 7.5 of the SLVSDQ6A datasheet under "Vref" parameter for TL43xLIBx devices, and applies specifically to the TL431LIACDBZR variant.
Does TL431LIACDBZR require an external output capacitor for stability?
No, TL431LIACDBZR is internally compensated and remains stable without an external output capacitor between cathode and anode. However, if a load capacitor (CL) is used, Figure 12 in the SLVSDQ6A datasheet defines stability boundaries-capacitors outside the stable region may cause oscillation. For most applications, CL = 0 is recommended unless transient response demands it.
What is the maximum cathode current rating for TL431LIACDBZR?
The TL431LIACDBZR supports a continuous cathode current (IKA) range of 1 mA to 15 mA, as specified in Section 7.1 (Absolute Maximum Ratings) and Section 7.4 (Recommended Operating Conditions) of the SLVSDQ6A datasheet. Exceeding 15 mA risks permanent damage; operation below 1 mA fails to engage regulation mode.
How does the pinout of TL431LIACDBZR differ from TL432LI variants?
TL431LIACDBZR uses the TL431 pinout: Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE. TL432LI variants swap REF and CATHODE (Pin 1 = REF, Pin 2 = CATHODE), making them incompatible without PCB redesign. The "LI" suffix and "DBZR" package code confirm TL431LIACDBZR follows the standard TL431 pin configuration.
Can TL431LIACDBZR operate in open-loop comparator mode?
Yes, TL431LIACDBZR functions as a comparator with integrated 2.495 V reference in open-loop mode. When cathode current ≥1 mA is supplied and no feedback is applied to the REF pin, it compares the REF pin voltage to its internal reference and drives the cathode low when the condition is met-enabling brown-out detection and threshold monitoring without external components.
TL431LIACDBZR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- 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:
- 15 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
TL431LIACDBZR FAQ
1.How can I place an order for TL431LIACDBZR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431LIACDBZR 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 TL431LIACDBZR reliable?
The price and inventory of TL431LIACDBZR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431LIACDBZR is usually 5 days.
3.What payment methods are accepted for TL431LIACDBZR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431LIACDBZR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431LIACDBZR?
TL431LIACDBZR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431LIACDBZR 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 TL431LIACDBZR?
For technical support, including TL431LIACDBZR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431LIACDBZR requirements.
6.How does Aetrix verify that TL431LIACDBZR is sourced from the original manufacturer or authorized distributors?
All TL431LIACDBZR 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 TL431LIACDBZR meets industry standards.
7.What is the process for return or replacement of TL431LIACDBZR?
All TL431LIACDBZR units undergo pre-shipment inspection (PSI). If there is an issue with TL431LIACDBZR, 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 TL431LIACDBZR part is unused and in its original packaging.
Return procedure for TL431LIACDBZR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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