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Texas Instruments TL431BQLPE3
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- Part No.:
- TL431BQLPE3
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
TL431BQLPE3.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,147
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Product details
Overview
TL431BQLPE3 from Texas Instruments is a precision programmable shunt voltage reference IC with 0.5% initial tolerance at 25°C, adjustable output from 2.483 V to 25.07 V via two external resistors, 14 mV max reference voltage deviation over −40°C to +125°C, 0.2 Ω typical dynamic impedance, and sink-current capability from 1 mA to 100 mA - used in secondary-side regulation of isolated flyback SMPSs.
For engineers reviewing the TL431BQLPE3 datasheet, TL431BQLPE3 pinout, TL431BQLPE3 application, or TL431BQLPE3 equivalent, this page delivers verified electrical specs, thermal performance data, package mapping to SOT-23-3, functional pin roles, real-world use cases in power supply feedback loops, and validated alternative parts for automotive-grade voltage referencing.
Technical Context
The TL431BQLPE3 implements a three-terminal adjustable shunt regulator architecture with an internal 2.495 V reference amplifier, error amplifier, and NPN output transistor - enabling sharp turn-on and stable regulation across wide load and temperature ranges. Its Q-grade rating confirms qualification for −40°C to +125°C operation with guaranteed VI(dev) ≤ 34 mV.
It operates as a voltage-controlled current sink: when the REF pin voltage exceeds Vref, the cathode-anode path conducts, sinking current up to 100 mA. The device requires no external compensation in standard configurations and maintains 0.2 Ω dynamic impedance below 1 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Vref tolerance | ±0.5% at 25°C (2483–2507 mV), enabling high-accuracy feedback in regulated power supplies |
| Temp range | −40°C to +125°C (Q grade), qualified for under-hood automotive and industrial control applications |
| Voltage adjust range | 2.483 V to 36 V via R1/R2 divider, supporting both low-voltage logic references and high-side biasing |
| Dynamic impedance | 0.2 Ω typical (≤0.5 Ω max), ensuring minimal output perturbation during transient load steps |
| Cathode current | 1–100 mA sink capability, sufficient for driving optocoupler LEDs in isolated SMPS feedback paths |
| Ref input current | 2–4 µA typical, minimizing resistor-divider loading error and enabling high-impedance sensing |
| VI(dev) | ≤34 mV over full temperature range, guaranteeing <±1.4 mV/V cathode voltage sensitivity in closed-loop designs |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm body), surface-mount, lead-free, RoHS-compliant, with thermal pad not connected internally.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (CATHODE) | Current sink output | Connects to SMPS transformer secondary or feedback node; sinks current when REF > Vref |
| Pin 2 (REF) | Reference input threshold | High-impedance sense node tied to resistor divider; triggers regulation at 2.495 V ±0.5% |
| Pin 3 (ANODE) | Common return / ground reference | Typically connected to system ground or negative rail; defines all voltage measurements |
Key Features
| Feature | Design Value |
|---|---|
| Sharp turn-on characteristic | Enables clean switching behavior in comparator-mode applications without hysteresis circuitry |
| Low output noise | Supports stable feedback in low-noise analog systems and precision ADC reference buffers |
| Zener diode replacement | Provides superior thermal stability and tighter tolerance vs. discrete Zeners in voltage clamping |
| Integrated reference + error amp | Eliminates need for external reference IC and op-amp in basic regulation circuits |
Applications
| Isolated Flyback SMPS Regulation | Voltage Monitoring & Protection |
|---|---|
Use Scenario: Secondary-side feedback loop in 12 V/5 A automotive DC-DC converter with optocoupler isolation. IC Role / Device Role / Timing Role: Shunt reference providing precise 5.0 V setpoint to optocoupler LED driver; regulates output by modulating primary-side PWM duty cycle. Use Value: Enables ±1% output accuracy over temperature and line variations, meeting AEC-Q100 Grade 1 requirements. | Use Scenario: Overvoltage lockout circuit monitoring 24 V industrial bus voltage. IC Role / Device Role / Timing Role: Adjustable threshold detector comparing bus voltage against 26.5 V trip point using resistor divider on REF pin. Use Value: Provides fast, accurate shutdown response with <1 µs propagation delay and no external hysteresis needed. |
| Zener Diode Replacement | Programmable Current Sink |
Use Scenario: Replacing 5.1 V Zener in telecom line-card bias supply. IC Role / Device Role / Timing Role: Precision shunt regulator maintaining stable 5.1 V reference despite input ripple and ambient drift. Use Value: Reduces voltage drift from ±50 mV (Zener) to ±12 mV over −40°C to +85°C, improving system calibration stability. | Use Scenario: Constant-current LED driver for status indicators in medical equipment. IC Role / Device Role / Timing Role: Configured as adjustable current sink (IKA = Vref/Rsense) delivering 20 mA ±0.1 mA. Use Value: Achieves <0.5% current accuracy without trimming, leveraging 0.5% Vref tolerance and low Iref error. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBZR | Same B-grade accuracy and Q-temp range, but in SOT-23-3 with different marking and tape/reel packaging | Identical electrical performance; differs only in reel orientation and date code format | Select when requiring TI's standard DBZ reel configuration for automated assembly |
| AS431ARTDT-33 | 0.5% tolerance, −40°C to +125°C, but higher 2.5 µA max Iref and 0.35 Ω max zKA | Acceptable in non-critical feedback loops; may require larger R1/R2 values to limit divider error | Choose for cost-sensitive designs where 0.15 Ω higher impedance and 1 µA extra Iref are acceptable |
Compared with TL431BQLPE3, TL431BIDBZR offers identical performance in a functionally equivalent package, while AS431ARTDT-33 trades minor impedance and input current penalties for lower unit cost in volume production.
Availability
TL431BQLPE3 is available at Aetrix Electronics and suitable for automotive power conversion, industrial voltage monitoring, precision current sinking, and isolated feedback loop design requiring stable component supply across extended temperature ranges.
Supply support for TL431BQLPE3 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 designing analog ICs, embedded processors, and digital signal solutions for industrial, automotive, and consumer markets.
The TL431 product line delivers precision programmable shunt references optimized for high-reliability feedback control in isolated power supplies, battery management, and safety-critical voltage supervision systems.
FAQ
What is the maximum cathode voltage rating for TL431BQLPE3?
The absolute maximum cathode-to-anode voltage (VKA) for TL431BQLPE3 is 37 V, with recommended operating range from Vref (2.483 V) to 36 V. Exceeding 37 V risks permanent damage per TI's SLVS543P datasheet Section 7.1. This rating enables direct use in 24 V and 32 V industrial bus monitoring without external clamping.
Does TL431BQLPE3 require external compensation in standard feedback configurations?
No, TL431BQLPE3 does not require external compensation in typical resistor-divider feedback setups. Its internal architecture provides inherent phase margin stability up to 100 kHz, as confirmed in TI's Application Report SLVA272. Compensation is only needed when driving capacitive loads >1 nF or integrating into high-gain control loops with additional poles.
How does the TL431BQLPE3 differ from TL431BCLPE3?
TL431BQLPE3 is rated for −40°C to +125°C (Q grade), while TL431BCLPE3 is limited to 0°C to +70°C (C grade). Both share identical 0.5% Vref tolerance and SOT-23-3 packaging, but TL431BQLPE3 guarantees VI(dev) ≤34 mV over its full range versus ≤16 mV for the C grade - making it mandatory for under-hood automotive use.
Can TL431BQLPE3 be used as a comparator with integrated reference?
Yes, TL431BQLPE3 functions as a precision comparator with built-in 2.495 V reference: when REF pin voltage exceeds Vref, the cathode sinks current. Its sharp turn-on and 1 µs typical response time (per Figure 22) support reliable threshold detection without external hysteresis in voltage-monitoring applications.
What is the minimum cathode current required for regulation in TL431BQLPE3?
The minimum cathode current (Imin) for stable regulation in TL431BQLPE3 is 0.4 mA (typical) and 0.7 mA (max) across −40°C to +125°C, per Section 7.13 of SLVS543P. This ensures reliable startup and regulation even with high-value feedback resistors, such as 1 MΩ dividers drawing <0.5 mA.
TL431BQLPE3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- Series:
- -
- Packaging:
- Bulk
- 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
TL431BQLPE3 FAQ
1.How can I place an order for TL431BQLPE3 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BQLPE3 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 TL431BQLPE3 reliable?
The price and inventory of TL431BQLPE3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BQLPE3 is usually 5 days.
3.What payment methods are accepted for TL431BQLPE3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BQLPE3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BQLPE3?
TL431BQLPE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BQLPE3 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 TL431BQLPE3?
For technical support, including TL431BQLPE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BQLPE3 requirements.
6.How does Aetrix verify that TL431BQLPE3 is sourced from the original manufacturer or authorized distributors?
All TL431BQLPE3 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 TL431BQLPE3 meets industry standards.
7.What is the process for return or replacement of TL431BQLPE3?
All TL431BQLPE3 units undergo pre-shipment inspection (PSI). If there is an issue with TL431BQLPE3, 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 TL431BQLPE3 part is unused and in its original packaging.
Return procedure for TL431BQLPE3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BQLPE3 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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LM4040DIM3-2.5/NOPB
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AZ431LANTR-G1
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