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Texas Instruments TL1431QLPR
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- Part No.:
- TL1431QLPR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
TL1431QLPR.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,648
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Product details
Overview
TL1431QLPR from Texas Instruments is a precision programmable shunt voltage reference IC operating as a 2.5-V adjustable reference with ±0.4% initial tolerance at 25°C, 0.2-Ω typical output impedance, and sink current capability from 1 mA to 100 mA. It functions as a Zener diode replacement in secondary-side regulation of flyback SMPSs, voltage monitoring, and comparator circuits requiring stable internal reference.
For engineers reviewing the TL1431QLPR datasheet, TL1431QLPR pinout, TL1431QLPR application, or TL1431QLPR equivalent, this page delivers verified automotive-grade specifications (–40°C to 125°C), exact pin mapping for TO-92 package, confirmed thermal performance (RθJA = 157°C/W), and two validated alternative parts for design continuity.
Technical Context
The TL1431QLPR integrates a precision 2.5-V bandgap reference and high-gain error amplifier in a single monolithic structure. Its Darlington output stage enables 100-mA sink current while maintaining sharp turnon (500 ns) and low dynamic impedance (0.2 Ω).
It operates in open-loop mode as a comparator with integrated reference or closed-loop mode as a shunt regulator-requiring external resistive feedback between CATHODE and REF pins to set output voltage from 2.5 V to 36 V. Minimum cathode current (Imin = 0.45 mA at 25°C) ensures linear operation and gain stability without mandatory output capacitance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VI(ref) | 2.500 V ±10 mV at 25°C - defines precise regulation threshold for feedback networks |
| Voltage Tolerance | ±0.4% at 25°C - enables high-accuracy voltage setting without trimming |
| Output Impedance | 0.2 Ω typical - minimizes load-induced voltage droop under varying cathode current |
| Sink Current Range | 1 mA to 100 mA - supports wide-range regulation and error amplification drive capability |
| Operating Temp | –40°C to +125°C - qualified for automotive under-hood and industrial control environments |
| Turnon Time | 500 ns - ensures fast response in overvoltage protection and dynamic regulation loops |
| Reference Input Current | 1.5–2.5 µA at 25°C - low bias requirement simplifies high-impedance feedback resistor selection |
Pinout & Package
TL1431QLPR is supplied in a 3-pin TO-92 package (body size 4.83 mm × 3.68 mm) with lead finish matte tin. Pin 1 is ANODE (internally connected to ground reference), Pin 2 is CATHODE (shunt current/voltage input), and Pin 3 is REF (reference input terminal).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1: ANODE | Common reference node | Internally tied to ground; serves as return path for cathode current and reference bias |
| Pin 2: CATHODE | Shunt current input/output | Accepts regulated sink current (1–100 mA); voltage at this pin is set by external R1/R2 divider |
| Pin 3: REF | Reference input | High-impedance input sensing point; must be driven with ≥5 µA to maintain amplifier bias and regulation |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage | 2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-voltage references |
| Thermal stability | VI(dev) ≤ 55 mV over –40°C to +125°C - ensures consistent regulation across automotive temperature extremes |
| Internal compensation | Stable without output capacitor - reduces BOM count and layout sensitivity in space-constrained designs |
| Zener replacement capability | Programmable knee voltage with sharp turnon - replaces discrete Zener diodes while improving accuracy and temperature drift |
| ESD robustness | ±2000 V HBM, ±1000 V CDM - meets automotive ESD requirements per JS-001 and JESD22-C101 |
Applications
| Secondary-Side Flyback Regulation | Voltage Monitoring & Threshold Detection |
|---|---|
Use Scenario: Isolated DC-DC converter where primary-side controller receives feedback from secondary-side output via optocoupler. IC Role / Device Role / Timing Role: TL1431QLPR acts as precision shunt regulator on secondary side, generating stable reference for optocoupler LED drive. Use Value: Enables ±1% output regulation across line/load/temperature without primary-side compensation redesign. | Use Scenario: Microcontroller-based system monitoring battery or rail voltage for brownout or overvoltage alerts. IC Role / Device Role / Timing Role: TL1431QLPR functions as comparator with integrated 2.5-V reference, triggering logic-level output when input exceeds programmed threshold. Use Value: Eliminates external reference IC and reduces component count while maintaining 0.4% trip-point accuracy. |
| Adjustable Linear Regulator Error Amplifier | Zener Diode Replacement in Bias Networks |
Use Scenario: Low-noise LDO design requiring fine-tuned output voltage and high PSRR. IC Role / Device Role / Timing Role: TL1431QLPR serves as error amplifier comparing feedback voltage to internal 2.5-V reference, driving pass transistor gate. Use Value: Achieves <100 ppm/°C thermal drift and 0.2-Ω output impedance for improved load regulation vs. discrete op-amp + reference solutions. | Use Scenario: High-reliability analog front-end requiring stable bias voltage for sensor excitation or amplifier offset nulling. IC Role / Device Role / Timing Role: TL1431QLPR replaces 2.5-V Zener diode with programmable, low-impedance, temperature-stable reference node. Use Value: Reduces voltage drift from >10 mV/°C (Zener) to <0.5 mV/°C and improves long-term stability by eliminating Zener aging effects. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431QPK | Same 2.5-V reference, ±0.5% initial tolerance, SOT-23-3 package, RθJA = 213°C/W | Higher thermal resistance limits power dissipation in compact layouts; not drop-in due to different pinout (CATHODE/ANODE/REF vs. ANODE/CATHODE/REF) | Select when board space is critical and thermal derating is acceptable; requires PCB redesign. |
| LM4040C25IDBZR | Fixed 2.5-V shunt reference, ±0.5% tolerance, 65-µA max IREF, 50-mA max IK | No adjustable output; lower current capability restricts use in high-power regulation or error amp drive | Choose only for fixed-voltage, low-current biasing where programmability is unnecessary. |
Compared with TL431QPK and LM4040C25IDBZR, TL1431QLPR uniquely combines automotive temperature range (–40°C to +125°C), 100-mA sink capability, and TO-92 compatibility-making it the sole option for high-current, field-replaceable, thermally robust shunt regulation in legacy automotive modules.
Availability
TL1431QLPR is available at Aetrix Electronics and suitable for automotive power management, industrial SMPS feedback, and embedded voltage monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL1431QLPR 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 delivering analog and embedded processing solutions, with leadership in precision analog ICs and automotive-qualified components.
The TL1431 family was designed specifically for automotive and industrial shunt regulation-emphasizing thermal stability, high sink current, and Zener-replacement functionality in harsh environments.
FAQ
What is the maximum cathode voltage rating for TL1431QLPR?
The absolute maximum cathode voltage (VKA) for TL1431QLPR is 37 V, with recommended operating range up to 36 V. Exceeding 37 V risks permanent damage. This rating applies across the full –40°C to +125°C temperature range and is defined with respect to the ANODE pin.
Does TL1431QLPR require an external output capacitor for stability?
No, TL1431QLPR is internally compensated and remains stable without an output capacitor between CATHODE and ANODE. However, if used with capacitive loads (e.g., optocoupler LEDs), stability boundary charts in the datasheet (Figure 12) must be consulted to select appropriate CL values-especially above 10 nF.
Can TL1431QLPR be used as a standalone comparator?
Yes, TL1431QLPR operates reliably in open-loop comparator mode when CATHODE is supplied with ≥1 mA and REF is biased to a threshold voltage. Its integrated 2.5-V reference eliminates external reference components, and its 500-ns turnon supports fast edge detection in voltage-monitoring applications.
What is the minimum cathode current needed for regulation in TL1431QLPR?
The minimum cathode current (Imin) required for regulation in TL1431QLPR is 0.45 mA at 25°C, rising to 1 mA over the full –40°C to +125°C range. Below this, the internal amplifier exits linear region and regulation fails-so external bias networks must guarantee IKA ≥ 1 mA across all operating conditions.
How does the REF pin current affect accuracy in TL1431QLPR designs?
TL1431QLPR's REF pin draws 1.5–2.5 µA at 25°C (up to 4 µA over temperature). This current flows through R1 in feedback dividers, causing a voltage error: ΔV = IREF × R1. For 0.4% accuracy, R1 must be ≤10 kΩ when using 1% resistors-or ≤5 kΩ with 0.1% resistors-to limit this error to <1 mV.
TL1431QLPR 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):
- 2.5V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±0.4%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL1431QLPR FAQ
1.How can I place an order for TL1431QLPR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431QLPR 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 TL1431QLPR reliable?
The price and inventory of TL1431QLPR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431QLPR is usually 5 days.
3.What payment methods are accepted for TL1431QLPR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431QLPR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431QLPR?
TL1431QLPR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431QLPR 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 TL1431QLPR?
For technical support, including TL1431QLPR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431QLPR requirements.
6.How does Aetrix verify that TL1431QLPR is sourced from the original manufacturer or authorized distributors?
All TL1431QLPR 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 TL1431QLPR meets industry standards.
7.What is the process for return or replacement of TL1431QLPR?
All TL1431QLPR units undergo pre-shipment inspection (PSI). If there is an issue with TL1431QLPR, 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 TL1431QLPR part is unused and in its original packaging.
Return procedure for TL1431QLPR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431QLPR Tags
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