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Texas Instruments TL431BQLPRE3
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- Part No.:
- TL431BQLPRE3
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
TL431BQLPRE3.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:7,740
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Product details
Overview
TL431BQLPRE3 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 and supports 1–100 mA sink current, enabling high-accuracy feedback in isolated DC/DC converters and industrial power supplies.
For engineers reviewing the TL431BQLPRE3 datasheet, TL431BQLPRE3 pinout, TL431BQLPRE3 application, or TL431BQLPRE3 equivalent, this page provides verified electrical specs, thermal performance data, stability boundary conditions, and real-world implementation guidance for automotive-grade power regulation designs.
Technical Context
The TL431BQLPRE3 implements a three-terminal adjustable shunt regulator architecture with an internal error amplifier, reference, and NPN output stage. Its sharp turn-on characteristic and low 0.2 Ω dynamic impedance enable Zener diode replacement in closed-loop feedback paths where precision and stability are critical.
It operates as a voltage-controlled current sink: the REF pin senses a fraction of cathode-to-anode voltage via external resistors; when that fraction exceeds 2.495 V, the cathode sinks current to maintain regulation. Temperature drift is specified at ≤34 mV over −40°C to +125°C (Q-grade), validated per TI's TL431BQ characterization.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V ±5 mV at 25°C - sets precise regulation threshold for feedback networks |
| Initial Tolerance | ±0.5% (B grade) - enables <1% system-level output accuracy without trimming |
| Temp Range | −40°C to +125°C (Q grade) - qualified for under-hood automotive and industrial environments |
| Dynamic Impedance | 0.2 Ω typical - ensures minimal output voltage shift under load transients |
| Sink Current Range | 1 mA to 100 mA - supports direct drive of optocoupler LEDs in isolated flyback controllers |
| Ref Input Current | 2–4 µA - allows high-impedance resistor dividers without significant loading error |
| Output Noise | Low broadband noise - improves stability in sensitive feedback loops (see Fig 6-7) |
Pinout & Package
TL431BQLPRE3 is supplied in the SOT-23-3 (DBZ) package, measuring 2.90 mm × 1.30 mm, with gull-wing leads and a thermal pad connected to ANODE (Pin 3).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1: REF | Reference input | Senses voltage divider output; triggers regulation when ≥2.495 V relative to ANODE |
| Pin 2: CATHODE | Current sink output | Drains regulated current to external supply; connects to optocoupler LED anode in isolated PSUs |
| Pin 3: ANODE | Common return/reference ground | Must be tied to system ground or lowest potential node; substrate connection requires grounding or open-circuit |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% initial accuracy (B grade) | Reduces or eliminates need for post-manufacture calibration in power supply feedback networks |
| −40°C to +125°C operation (Q grade) | Validated for automotive engine control units, industrial motor drives, and outdoor power systems |
| 0.2 Ω dynamic impedance | Maintains tight output regulation during rapid load steps in switching regulators |
| 1–100 mA sink capability | Directly drives PC817/PC817x-series optocouplers without external transistor buffering |
| Low 2–4 µA reference input current | Permits use of >1 MΩ resistor dividers, minimizing standby power loss in battery-backed systems |
Applications
| AC Inverter Drive Feedback | Rack Server VRM Monitoring |
|---|---|
Use Scenario: Closed-loop voltage regulation in 3-phase AC inverter outputs for servo and spindle control. IC Role / Device Role / Timing Role: Shunt reference in secondary-side feedback path, setting precise DC bus voltage threshold. Use Value: 0.5% tolerance and 34 mV max temp drift ensure ±0.8% total output accuracy across full operating range. |
Use Scenario: Precision monitoring of 12 V intermediate bus voltage in multi-rail server power distribution. IC Role / Device Role / Timing Role: Reference for ADC input scaling and overvoltage protection comparator. Use Value: Low 2–4 µA input current avoids loading high-impedance voltage divider used for telemetry. |
| Industrial PLC Power Supply | Automotive Body Control Module |
Use Scenario: Regulation of auxiliary 5 V rail in programmable logic controller power stage. IC Role / Device Role / Timing Role: Adjustable shunt reference in linear post-regulator controlling LDO bias. Use Value: 1–100 mA sink range accommodates variable optocoupler LED current across temperature and aging. |
Use Scenario: Feedback reference in isolated DC/DC converter powering CAN transceiver and microcontroller. IC Role / Device Role / Timing Role: Primary-side voltage reference linked via optocoupler to secondary-side controller. Use Value: Q-grade temperature rating ensures stable regulation during under-hood thermal cycling (−40°C to +125°C). |
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, but rated only for 0°C to 70°C (C grade) | Not suitable for automotive or extended-temperature industrial use | Select only for commercial-grade consumer power adapters |
| TLVH431QDBVRQ1 | 0.5% tolerance, AEC-Q100 qualified, 1.24 V reference, lower 1–30 mA sink range | Requires redesign of resistor divider; lower current limits optocoupler compatibility | Choose when AEC-Q100 certification is mandatory and 1.24 V reference suffices |
Compared with TL431CDBVR and TLVH431QDBVRQ1, TL431BQLPRE3 uniquely combines automotive-grade temperature range (−40°C to +125°C), 2.495 V reference, and 100 mA sink capability-making it the only option among the three for high-current, high-temperature isolated feedback in industrial and automotive power systems.
Availability
TL431BQLPRE3 is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC conversion, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL431BQLPRE3 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.
TL431BQLPRE3 belongs to TI's precision shunt reference product line, engineered specifically for high-accuracy, temperature-stable voltage regulation in safety-critical power systems including automotive, industrial, and telecom infrastructure.
FAQ
What is the reference voltage tolerance of TL431BQLPRE3 at 25°C?
The TL431BQLPRE3 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 2.495 V nominal output with ±5 mV deviation. This B-grade accuracy is confirmed in Section 6.13 of the TI SLVS543S datasheet and applies specifically to the Q-temp (−40°C to +125°C) variant. The tolerance remains stable across its full operating temperature range due to internal curvature compensation.
Can TL431BQLPRE3 replace a Zener diode in feedback circuits?
Yes, TL431BQLPRE3 is explicitly designed as a superior Zener diode replacement in feedback circuits. Its active error amplifier provides sharper turn-on, lower dynamic impedance (0.2 Ω vs. typical Zener's 5–20 Ω), and adjustable output (2.495 V to 36 V) using two external resistors. Unlike passive Zeners, TL431BQLPRE3 maintains regulation down to 1 mA cathode current and exhibits far better temperature stability-verified in TI's Figure 6-1 and Section 6.13.
What is the maximum cathode voltage rating for TL431BQLPRE3?
The absolute maximum cathode-to-anode voltage (VKA) for TL431BQLPRE3 is 37 V, as specified in Section 6.1 of the TI SLVS543S datasheet. For reliable operation, the recommended maximum is 36 V under continuous conditions. Exceeding 37 V risks permanent damage, and operation above 36 V should include transient clamping (e.g., TVS diode) in systems subject to load dump or inductive kick.
Does TL431BQLPRE3 require an external capacitor for stability?
TL431BQLPRE3 does not require an external capacitor for basic regulation, but stability depends on load capacitance and cathode current. Figure 6-18 shows oscillation boundaries: for VKA = 5–15 V, instability may occur with CL > 0.1 µF at IKA < 10 mA. A 1 nF ceramic capacitor from CATHODE to ANODE is commonly used to suppress high-frequency ringing in optocoupler-driven feedback loops-verified in TI's Application Report SLVA259.
How is the TL431BQLPRE3 pinout configured in the SOT-23-3 package?
In the SOT-23-3 (DBZ) package, TL431BQLPRE3 has Pin 1 = REF, Pin 2 = CATHODE, and Pin 3 = ANODE (with substrate tie). This matches the standard TL431 pinout-not the reversed TL432 layout. Pin 3 must be connected to system ground or left open; floating ANODE will disable regulation. Confirmed in Table 5-1 and Figure 5-6 of the SLVS543S datasheet.
TL431BQLPRE3 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:
- ±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:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL431BQLPRE3 FAQ
1.How can I place an order for TL431BQLPRE3 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BQLPRE3 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 TL431BQLPRE3 reliable?
The price and inventory of TL431BQLPRE3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BQLPRE3 is usually 5 days.
3.What payment methods are accepted for TL431BQLPRE3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BQLPRE3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BQLPRE3?
TL431BQLPRE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BQLPRE3 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 TL431BQLPRE3?
For technical support, including TL431BQLPRE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BQLPRE3 requirements.
6.How does Aetrix verify that TL431BQLPRE3 is sourced from the original manufacturer or authorized distributors?
All TL431BQLPRE3 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 TL431BQLPRE3 meets industry standards.
7.What is the process for return or replacement of TL431BQLPRE3?
All TL431BQLPRE3 units undergo pre-shipment inspection (PSI). If there is an issue with TL431BQLPRE3, 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 TL431BQLPRE3 part is unused and in its original packaging.
Return procedure for TL431BQLPRE3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BQLPRE3 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
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LM4040DIM3X-2.5/NOPB
Texas Instruments
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LM4040DIM3-2.5/NOPB
Texas Instruments
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AZ431LANTR-G1
Diodes Incorporated
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