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Texas Instruments TL1431CLPE3
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- Part No.:
- TL1431CLPE3
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
TL1431CLPE3.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,758
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Product details
Overview
TL1431CLPE3 from Texas Instruments is a precision programmable shunt voltage reference IC with 0.4% initial voltage tolerance, 2.5 V nominal reference voltage (adjustable up to 36 V), 0.2 Ω typical output impedance, and 500 ns fast turn-on time. It operates as a Zener diode replacement in secondary-side regulation of flyback SMPSs, voltage monitoring circuits, and adjustable current sources.
For engineers reviewing the TL1431CLPE3 datasheet, TL1431CLPE3 pinout, TL1431CLPE3 application, or TL1431CLPE3 equivalent, this page delivers verified electrical parameters, TO-92 package mapping, functional mode distinctions (open-loop comparator vs. closed-loop regulator), thermal performance data, and two validated alternative parts for design flexibility.
Technical Context
The TL1431CLPE3 integrates a 2.5 V bandgap reference and high-gain transconductance amplifier in a single monolithic structure. Its internal Darlington output stage enables sink current capability from 1 mA to 100 mA while maintaining sharp turn-on and low dynamic impedance.
It functions in two primary modes: open-loop (as a comparator with integrated reference) and closed-loop (as an error amplifier in shunt regulation). Stability is internally compensated-no external cathode-to-anode capacitor required-though load capacitance effects are characterized across 0.001–100 µF in Figure 5-12.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V ±10 mV at 25°C; supports precise voltage setting from 2.5 V to 36 V via external resistor divider |
| Initial Tolerance | ±0.4% at 25°C; ensures tight output accuracy without trimming in production power supplies |
| Output Impedance | 0.2 Ω typical at 1–100 mA; minimizes load-induced voltage drift in feedback loops |
| Turn-on Time | 500 ns; enables rapid response in overvoltage clamp and transient detection circuits |
| Operating Temperature | 0°C to +70°C (commercial grade); validated for stable operation across full range |
| Cathode Current Range | 1 mA to 100 mA sink capability; supports both low-power sensing and higher-current regulation |
| Reference Input Current | 1.5–2.5 µA typical at 25°C; allows high-value feedback resistors to minimize power loss |
Pinout & Package
TL1431CLPE3 is supplied in the TO-92 (LP) package: 4.83 mm × 3.68 mm body, 3-pin through-hole format with standard JEDEC TO-92 outline. Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Current-sink output terminal | Primary output node; sinks regulated current to maintain reference voltage at REF; connects to supply rail or feedback network |
| ANODE (Pin 2) | Common return / ground reference | Internal connection point for all ANODE terminals; must be tied to system ground or lowest potential node in shunt configuration |
| REF (Pin 3) | Reference input / error sense node | Senses voltage relative to ANODE; when driven to 2.5 V, forces CATHODE to programmed output; requires ≥5 µA bias current |
Key Features
| Feature | Design Value |
|---|---|
| Zener diode replacement | Enables programmable breakdown voltage (2.5–36 V) with superior thermal stability and lower impedance than discrete Zeners |
| Integrated reference + amplifier | Combines precision 2.5 V reference and high-gain op-amp in one die-eliminates external components in comparator or error amp designs |
| Internally compensated stability | No mandatory cathode-to-anode capacitor needed; simplifies layout and avoids instability risks from parasitic capacitance |
| Low reference current | Typical 2.5 µA at 25°C allows use of >100 kΩ feedback resistors-reducing power consumption and thermal drift in precision dividers |
| Fast turn-on | 500 ns propagation enables real-time overvoltage clamping and fast-response protection circuits |
Applications
| Secondary-Side Flyback Regulation | Voltage Monitoring & Clamping |
|---|---|
Use Scenario: Isolated DC-DC converter where primary-side controller lacks direct output sensing. IC Role / Device Role / Timing Role: Shunt regulator providing isolated feedback signal to optocoupler LED; sets precise output voltage via resistor divider on secondary side. Use Value: Enables ±1% output regulation without transformer auxiliary winding or secondary-side controller IC. |
Use Scenario: Overvoltage protection circuit in industrial power rails or battery management systems. IC Role / Device Role / Timing Role: Precision clamp triggered when sensed voltage exceeds threshold; sinks current to limit rail excursion. Use Value: 0.4% reference tolerance and 500 ns response ensure reliable, repeatable trip points under transient stress. |
| Adjustable Current Source | Comparator with Integrated Reference |
Use Scenario: Constant-current LED driver or sensor excitation circuit requiring stable current independent of supply variation. IC Role / Device Role / Timing Role: Regulates current through external pass transistor by holding reference voltage across sense resistor. Use Value: Low 0.2 Ω output impedance maintains current accuracy despite load or temperature shifts. |
Use Scenario: Threshold detection in microcontroller-based systems where external reference ICs add cost and board space. IC Role / Device Role / Timing Role: Open-loop comparator comparing analog signal to built-in 2.5 V reference; drives digital input or fault flag. Use Value: Eliminates need for separate voltage reference and op-amp-reducing BOM count and PCB area by 2 components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBZR | Same 2.5 V reference, 0.5% initial tolerance (vs. TL1431CLPE3's 0.4%), SO-8 package, higher 0.3 Ω typical output impedance | Requires PCB redesign for surface-mount; slightly reduced accuracy affects tight-tolerance SMPS designs | Select when SMT assembly is mandatory and ±0.5% tolerance suffices; verify thermal derating in TO-92-restricted layouts |
| LM431ACM | 2.5 V reference, 1% initial tolerance, TO-92 package, 0.5 Ω typical output impedance, slower 1 µs turn-on | Compatible footprint but lower accuracy and higher impedance limit use in high-precision or fast-clamp roles | Choose for cost-sensitive, non-critical applications where 1% tolerance and µs-level response are acceptable |
Compared with TL431CDBZR and LM431ACM, TL1431CLPE3 offers the tightest initial tolerance (0.4%) and lowest output impedance (0.2 Ω) in the TO-92 form factor-making it optimal for high-accuracy, low-drift shunt regulation where through-hole mounting is preferred.
Availability
TL1431CLPE3 is available at Aetrix Electronics and suitable for secondary-side regulation in flyback SMPSs, voltage monitoring circuits, and adjustable current sources requiring stable component supply across commercial temperature ranges.
Supply support for TL1431CLPE3 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.
The TL1431 family was designed as a precision, programmable shunt reference for power supply feedback, voltage supervision, and analog signal conditioning-targeting cost-sensitive yet accuracy-demanding applications across commercial and industrial systems.
FAQ
What is the maximum cathode voltage rating for TL1431CLPE3?
The absolute maximum cathode voltage (VKA) for TL1431CLPE3 is 37 V, with recommended operating range up to 36 V referenced to the ANODE pin. Exceeding 37 V risks permanent damage. This rating enables safe use in 24 V and 36 V industrial power rails and flyback outputs without additional clamping.
Can TL1431CLPE3 operate as a standalone comparator?
Yes, TL1431CLPE3 can operate in open-loop mode as a comparator with integrated 2.5 V reference. When the REF pin voltage exceeds 2.5 V, the CATHODE sinks current; below 2.5 V, it remains off. This eliminates the need for external reference and op-amp in simple threshold-detection circuits using TL1431CLPE3.
What is the minimum cathode current required for regulation in TL1431CLPE3?
The minimum cathode current (Imin) for stable regulation in TL1431CLPE3 is 0.45 mA at 25°C, rising to 1 mA across the full 0°C to 70°C range. Supplying less than this prevents the internal amplifier from entering linear region, causing loss of regulation and unpredictable output behavior in TL1431CLPE3 circuits.
Does TL1431CLPE3 require an external capacitor for stability?
No, TL1431CLPE3 is internally compensated and stable without any cathode-to-anode capacitor. However, if external capacitance is added (e.g., for EMI filtering or transient suppression), designers must consult Figure 5-12 in the datasheet to avoid oscillation-capacitance values above ~10 nF may require series resistance to maintain stability in TL1431CLPE3 applications.
How does the TO-92 package affect thermal performance of TL1431CLPE3?
In the TO-92 (LP) package, TL1431CLPE3 has a junction-to-ambient thermal resistance (RθJA) of 157°C/W. At 100 mA cathode current and 5 V drop, power dissipation reaches 0.5 W-raising junction temperature by ~78.5°C above ambient. Adequate PCB copper pour or forced airflow is recommended to keep TL1431CLPE3 within its 150°C max junction limit.
TL1431CLPE3 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):
- 2.5V
- 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL1431CLPE3 FAQ
1.How can I place an order for TL1431CLPE3 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431CLPE3 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 TL1431CLPE3 reliable?
The price and inventory of TL1431CLPE3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431CLPE3 is usually 5 days.
3.What payment methods are accepted for TL1431CLPE3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431CLPE3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431CLPE3?
TL1431CLPE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431CLPE3 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 TL1431CLPE3?
For technical support, including TL1431CLPE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431CLPE3 requirements.
6.How does Aetrix verify that TL1431CLPE3 is sourced from the original manufacturer or authorized distributors?
All TL1431CLPE3 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 TL1431CLPE3 meets industry standards.
7.What is the process for return or replacement of TL1431CLPE3?
All TL1431CLPE3 units undergo pre-shipment inspection (PSI). If there is an issue with TL1431CLPE3, 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 TL1431CLPE3 part is unused and in its original packaging.
Return procedure for TL1431CLPE3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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