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Texas Instruments TL1431QPWR
- Part No.:
- TL1431QPWR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
TL1431QPWR.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,102
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Product details
Overview
TL1431QPWR from Texas Instruments is an automotive-grade precision programmable shunt voltage reference IC, functioning as a 2.5-V internal reference with adjustable output (2.5 V to 36 V) via external resistors, 0.4% initial tolerance at 25°C, 0.2-Ω typical output impedance, and sink current capability from 1 mA to 100 mA - widely used in secondary-side regulation of flyback SMPSs.
For engineers reviewing the TL1431QPWR datasheet, TL1431QPWR pinout, TL1431QPWR application, or TL1431QPWR equivalent, this page delivers verified electrical specs, automotive temperature range (–40°C to 125°C), TSSOP-8 package mapping, functional modes (open-loop comparator / closed-loop error amplifier), and real-world design implications for stability, accuracy, and Zener replacement.
Technical Context
The TL1431QPWR integrates a precision 2.5-V bandgap reference and high-gain transconductance amplifier driving an NPN Darlington output stage, enabling sharp turnon (500 ns) and stable shunt regulation without external compensation. Its internal architecture supports both open-loop comparator operation (with integrated reference) and closed-loop error amplification via cathode-to-ref feedback.
It operates across –40°C to 125°C with VI(ref) deviation ≤55 mV over full range, ΔVI(ref)/ΔVKA ≤ –2 mV/V, and II(ref) ≤ 4 µA max - all specified under IKA = 10 mA. The device requires ≥1 mA cathode current to enter regulation and mandates ≥5 µA reference pin current to bias its input transistor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VI(ref)) | 2.500 V ±10 mV at 25°C; enables precise setpoint generation for feedback loops |
| Initial Tolerance | ±0.4% at 25°C; ensures <±10 mV absolute error before temperature or load effects |
| Output Impedance (|zKA|) | 0.2 Ω typical (≤0.4 Ω max); minimizes output voltage droop under dynamic load changes |
| Sink Current Range | 1 mA to 100 mA; supports direct interface with optocoupler LEDs or power-stage error amplifiers |
| Operating Temperature | –40°C to +125°C; qualified for automotive under-hood and industrial control environments |
| Cathode Voltage Range | 2.5 V to 36 V; allows wide-range output programming using two external resistors |
| Turnon Time | 500 ns typical; enables fast response in overvoltage protection and transient detection circuits |
Pinout & Package
TSSOP-8 package (4.40 mm × 3.00 mm body), moisture sensitivity level 1, lead-free and RoHS compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current/voltage output node | Main current-sinking terminal; connects to SMPS output or optocoupler anode; must be biased ≥2.5 V above ANODE |
| ANODE (Pin 2) | Common reference ground | Internal connection point for all internal circuitry; tied to system ground or return path; not floating |
| REF (Pin 3) | Reference input threshold | Senses voltage relative to ANODE; requires ≥5 µA input current; forms feedback node with R1/R2 divider |
| NC (Pins 4–8) | No internal connection | Unbonded pins; must remain unconnected; no routing or thermal tie required |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable shunt regulation | Programmable 2.5 V to 36 V output using only two external resistors - eliminates need for multiple Zener diodes |
| Automotive qualification | Specified and tested over –40°C to +125°C ambient; meets AEC-Q100 stress requirements for automotive power systems |
| Low-output-impedance sink | 0.2 Ω typical dynamic impedance ensures <25 mV output shift across 10–100 mA load steps - critical for tight-regulation SMPS designs |
| Integrated reference + amplifier | Single-chip solution replaces discrete op amp + voltage reference combos - reduces BOM count and layout area in feedback networks |
| Fast comparator mode | 500 ns turnon enables sub-microsecond overvoltage detection and latch-triggering without external hysteresis components |
Applications
| Secondary-Side Flyback Regulation | Zener Diode Replacement |
|---|---|
Use Scenario: Isolated DC-DC converter where primary-side controller receives feedback via optocoupler from secondary-side output. IC Role / Device Role / Timing Role: TL1431QPWR acts as precision shunt regulator and error amplifier, comparing output voltage against 2.5-V reference and driving optocoupler LED current proportional to error. Use Value: Enables ±1% output regulation across line/load/temperature; replaces 5% tolerance Zeners and improves cross-regulation in multi-output converters. |
Use Scenario: Low-cost voltage clamping or reference generation in non-isolated supplies, battery monitors, or protection circuits. IC Role / Device Role / Timing Role: TL1431QPWR functions as programmable 2.5–36 V shunt reference, sinking current when cathode voltage exceeds programmed threshold. Use Value: Delivers 0.4% initial accuracy vs. ±5% Zener tolerance; supports tighter voltage margins and higher reliability in automotive sensor interfaces. |
| Voltage Monitoring & Supervision | Comparator with Integrated Reference |
Use Scenario: Real-time monitoring of 12 V or 24 V rail integrity in automotive ECUs or industrial PLCs. IC Role / Device Role / Timing Role: TL1431QPWR operates in open-loop comparator mode, asserting fault signal when monitored voltage crosses user-defined threshold. Use Value: Eliminates need for external reference IC; 500 ns response time enables detection of fast transients (<1 µs) without added propagation delay. |
Use Scenario: Threshold detection in battery charge termination, overtemperature latching, or logic-level translation circuits. IC Role / Device Role / Timing Role: TL1431QPWR serves as self-contained comparator with built-in 2.5-V reference, comparing input against REF pin with rail-to-rail output swing capability. Use Value: Reduces component count by 2–3 parts (ref + comparator + pull-up); maintains accuracy over –40°C to 125°C without calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431QDBVR | Same 2.5-V reference, but rated for –40°C to 125°C in SOT-23-5; lower max cathode current (100 mA vs. TL1431QPWR's 100 mA), identical VI(ref) tolerance and tempco | Smaller footprint and lower thermal mass; less suitable for high-power dissipation (>300 mW) due to SOT-23 thermal resistance | Select TL431QDBVR for space-constrained PCBs where power dissipation stays below 200 mW and TSSOP-8 layout is impractical |
| LM4040CIM3-2.5/NOPB | Fixed 2.5-V shunt reference; no adjustable output; 0.5% initial tolerance; max sink current 15 mA; no Darlington output stage | Cannot replace TL1431QPWR in adjustable-voltage or >15 mA sink applications; limited to low-current precision references | Choose LM4040CIM3-2.5/NOPB only for fixed 2.5-V reference needs with ultra-low quiescent current (<70 µA) and minimal board area |
Compared with TL431QDBVR, TL1431QPWR offers identical automotive temperature rating but superior thermal performance in TSSOP-8 for higher-power regulation; versus LM4040CIM3-2.5/NOPB, it provides full adjustability and 6.7× higher sink current - making it irreplaceable in flyback feedback and active clamp designs.
Availability
TL1431QPWR is available at Aetrix Electronics and suitable for automotive power conversion, industrial voltage supervision, and isolated DC-DC feedback applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL1431QPWR 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 power management, signal chain, and automotive electronics.
The TL1431 product line was designed specifically for precision voltage referencing and error amplification in isolated power supplies and safety-critical monitoring systems - emphasizing automotive qualification, thermal stability, and ease of use in feedback networks.
FAQ
What is the maximum cathode voltage rating for TL1431QPWR?
The absolute maximum cathode voltage (VKA) for TL1431QPWR is 37 V, per the datasheet Absolute Maximum Ratings table. Operation up to 36 V is supported under recommended conditions. Exceeding 37 V risks permanent damage, even momentarily. This limit applies regardless of current level or temperature, and must be respected in all designs using TL1431QPWR.
Does TL1431QPWR require an external capacitor for stability?
No, TL1431QPWR is internally compensated and remains stable without an output capacitor between CATHODE and ANODE. However, if a load capacitor (CL) is present - such as in optocoupler-driven feedback loops - stability depends on CL value and cathode voltage; Figure 12 in the datasheet defines safe CL ranges for VKA = 5 V to 15 V. TL1431QPWR itself does not mandate external capacitance.
Can TL1431QPWR operate with less than 1 mA cathode current?
No - TL1431QPWR requires ≥1 mA cathode current (IKA) to maintain regulation and linear operation. Below this threshold, the device exits regulation and behaves unpredictably. The datasheet specifies Imin = 0.45–1 mA (typ/max) at 25°C. For reliable closed-loop performance in applications like SMPS feedback, design for ≥2 mA minimum IKA to ensure margin across temperature and part variation.
What is the function of the ANODE pin on TL1431QPWR?
The ANODE pin on TL1431QPWR serves as the common reference node and internal ground for all internal circuitry, including the reference and amplifier stages. It must be connected to system ground or the lowest potential point in the shunt path. All voltage specifications - including VI(ref), VKA, and II(ref) - are referenced to ANODE. Leaving ANODE floating or misrouting it will prevent TL1431QPWR from functioning.
How does temperature affect the reference voltage accuracy of TL1431QPWR?
Over –40°C to +125°C, TL1431QPWR exhibits VI(dev) ≤ 55 mV total deviation from nominal 2.500 V, corresponding to ±2.2% full-scale drift. This is specified in Section 6.6 of the datasheet. The average temperature coefficient αVI(ref) is calculated as VI(dev)/(2500 mV × ΔTA) × 10⁶, yielding ~92 ppm/°C worst-case. Designers must include this drift in total output error budgets for high-accuracy applications using TL1431QPWR.
TL1431QPWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- 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:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
TL1431QPWR FAQ
1.How can I place an order for TL1431QPWR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431QPWR 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 TL1431QPWR reliable?
The price and inventory of TL1431QPWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431QPWR is usually 5 days.
3.What payment methods are accepted for TL1431QPWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431QPWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431QPWR?
TL1431QPWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431QPWR 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 TL1431QPWR?
For technical support, including TL1431QPWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431QPWR requirements.
6.How does Aetrix verify that TL1431QPWR is sourced from the original manufacturer or authorized distributors?
All TL1431QPWR 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 TL1431QPWR meets industry standards.
7.What is the process for return or replacement of TL1431QPWR?
All TL1431QPWR units undergo pre-shipment inspection (PSI). If there is an issue with TL1431QPWR, 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 TL1431QPWR part is unused and in its original packaging.
Return procedure for TL1431QPWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431QPWR Tags
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TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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AN431AN-ATRG1
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LM4040CYM3-2.5-TR
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LM4040CYM3-4.1-TR
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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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