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Texas Instruments TL1431CLPRE3
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- Part No.:
- TL1431CLPRE3
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
TL1431CLPRE3.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,000
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Product details
Overview
TL1431CLPRE3 from Texas Instruments is a precision programmable shunt voltage reference IC with 0.4% initial voltage tolerance at 25°C, 2.500 V nominal reference voltage, 0.2 Ω typical output impedance, and adjustable output voltage range from 2.5 V to 36 V via external resistors. It operates as a Zener diode replacement in secondary-side regulation of flyback SMPSs.
For engineers reviewing the TL1431CLPRE3 datasheet, TL1431CLPRE3 pinout, TL1431CLPRE3 application, or TL1431CLPRE3 equivalent, key selection criteria include its 1 mA to 100 mA sink current capability, fast 500 ns turn-on time, low 1.5–2.5 µA reference input current, thermal stability across 0°C to 70°C, and compatibility with TO-92 package layout constraints.
Technical Context
The TL1431CLPRE3 integrates a precision 2.5 V bandgap reference and high-gain transconductance amplifier in a single monolithic structure. Its internal Darlington output stage enables up to 100 mA cathode sink current while maintaining sharp turn-on characteristics and low dynamic impedance.
It functions in two primary modes: open-loop comparator mode (using internal reference for threshold detection) and closed-loop shunt regulator mode (with resistive feedback from cathode to REF pin). Stability is internally compensated-no external capacitor required between cathode and anode for basic operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V ±10 mV at 25°C; sets precise regulation point for feedback networks |
| Initial Tolerance | ±0.4% at 25°C; ensures ≤10 mV absolute error in reference voltage without trimming |
| Output Impedance | 0.2 Ω typical at 1 kHz; minimizes cathode voltage shift under load current changes |
| Sink Current Range | 1 mA to 100 mA; supports direct regulation of moderate-power rails or error amplifier drive |
| Turn-on Time | 500 ns; enables fast response in overvoltage clamping and transient protection circuits |
| Operating Temperature | 0°C to 70°C (commercial grade); validated for stable performance in industrial power supplies |
| Reference Input Current | 1.5–2.5 µA at 25°C; allows high-impedance resistor dividers without significant loading error |
Pinout & Package
TL1431CLPRE3 is supplied in the TO-92 (LP) package: 3-pin through-hole plastic case, 4.83 mm × 3.68 mm body size, with leads spaced 0.1 inch (2.54 mm) apart. Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current output node | Carries regulated sink current; connects to positive rail or switching node in SMPS feedback |
| ANODE (Pin 2) | Common reference ground | Typically tied to system ground or return path; all voltages referenced to this node |
| REF (Pin 3) | Feedback input / reference threshold | Senses voltage divider midpoint; device regulates cathode-to-anode voltage to maintain 2.5 V at this pin |
Key Features
| Feature | Design Value |
|---|---|
| Zener diode replacement | Enables precise, temperature-stable voltage clamping without Zener's wide tolerance and drift |
| Adjustable output (2.5 V to 36 V) | Configured with two external resistors; supports flexible regulation without multiple fixed-reference SKUs |
| Low reference current (≤2.5 µA) | Permits use of >100 kΩ resistor dividers, reducing power loss and noise coupling in high-impedance feedback |
| Fast 500 ns turn-on | Provides rapid response for overvoltage protection and dynamic line/load regulation in SMPS control loops |
| Internally compensated | Operates stably without cathode-to-anode capacitor-simplifies layout and eliminates capacitor aging/ESR concerns |
Applications
| Secondary-Side Flyback Regulation | Zener Diode Replacement |
|---|---|
Use Scenario: Isolated DC-DC converter where feedback signal crosses transformer barrier via optocoupler. IC Role / Device Role / Timing Role: Shunt reference generating error signal on secondary side; drives optocoupler LED to regulate primary-side controller. Use Value: Replaces discrete Zener + transistor with ±5% tolerance by delivering ±0.4% reference accuracy and <0.2 Ω dynamic impedance for tighter output voltage regulation. |
Use Scenario: Overvoltage clamp protecting microcontroller I/O or analog front-end inputs. IC Role / Device Role / Timing Role: Precision voltage clamp activated when input exceeds programmed threshold (e.g., 5.1 V). Use Value: Eliminates Zener's 5–10% tolerance and high temperature coefficient; provides stable 5.1 V clamp with <10 mV error across 0°C–70°C. |
| Voltage Monitoring | Comparator with Integrated Reference |
Use Scenario: Battery voltage supervision in portable equipment or industrial sensors. IC Role / Device Role / Timing Role: Threshold detector comparing battery voltage against fixed reference using external resistor divider. Use Value: Integrates accurate 2.5 V reference and high-gain amplifier-no external reference IC or op-amp needed, reducing BOM count and PCB area. |
Use Scenario: Level-shifting or window detection in signal conditioning circuits. IC Role / Device Role / Timing Role: Open-loop comparator comparing input signal to internal 2.5 V reference without feedback. Use Value: Delivers fast 500 ns propagation delay and rail-to-rail output swing-enables clean digital transitions from analog signals without external 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, SOT-23-3 package; higher 3 µA max reference current | Requires surface-mount layout; less suitable for through-hole prototyping or high-vibration environments | Preferred for space-constrained designs where TO-92 footprint is unavailable |
| LM431ACM | 2.5 V reference, ±1.0% initial tolerance, SOIC-8 package; 10 µA max reference current; no guaranteed 500 ns turn-on | Lower accuracy and slower response limit use in precision regulation or fast-clamp roles | Cost-effective option where ±1% regulation and relaxed timing are acceptable |
Compared with TL1431CLPRE3, TL431CDBZR offers identical functionality in a smaller package but sacrifices mechanical robustness and ease of hand-soldering, while LM431ACM trades accuracy and speed for broader availability and lower unit cost in non-critical applications.
Availability
TL1431CLPRE3 is available at Aetrix Electronics and suitable for industrial power supplies, flyback SMPS feedback circuits, and precision voltage monitoring systems requiring stable component supply across extended production cycles.
Supply support for TL1431CLPRE3 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, specializing in analog, embedded processing, and power management technologies for industrial, automotive, and communications markets.
The TL1431 family was designed as a precision programmable shunt reference targeting cost-sensitive yet accuracy-demanding applications including isolated power supply regulation, voltage supervision, and comparator-based signal conditioning.
FAQ
What is the maximum cathode voltage rating for TL1431CLPRE3?
The absolute maximum cathode-to-anode voltage for TL1431CLPRE3 is 37 V. Operation above 36 V violates recommended conditions and risks permanent damage. This rating directly defines the upper limit of adjustable output voltage in shunt regulator configurations and must be respected in overvoltage clamp designs.
Can TL1431CLPRE3 operate without an external capacitor between cathode and anode?
Yes, TL1431CLPRE3 is internally compensated and remains stable without any external capacitor between cathode and anode. This simplifies design and eliminates capacitor-related failure modes. However, if downstream circuitry presents capacitive load or transient response enhancement is needed, stability boundary charts (Figure 5-12) must be consulted before adding capacitance.
What is the minimum cathode current required for regulation in TL1431CLPRE3?
TL1431CLPRE3 requires a minimum cathode current of 0.45 mA at 25°C to maintain regulation. Below this threshold, the internal amplifier exits linear region and reference accuracy degrades. Designers must ensure external bias network delivers ≥1 mA to guarantee margin across temperature and process variation.
How does TL1431CLPRE3 differ from standard Zener diodes in practical design?
TL1431CLPRE3 replaces Zener diodes by providing 0.4% initial tolerance versus typical Zener ±5%, 0.2 Ω dynamic impedance versus Zener's 10–100 Ω, and stable 2.5 V reference across 0°C–70°C. It also enables adjustable outputs via resistors-eliminating need for multiple Zener part numbers and improving long-term reliability in feedback paths.
Is TL1431CLPRE3 pin-compatible with other TL1431 variants like TL1431CDR?
No-TL1431CLPRE3 uses the TO-92 (3-pin) package with pinout CATHODE–ANODE–REF, while TL1431CDR uses SOIC-8 with different pin mapping and internal NC pins. Direct substitution requires PCB redesign. The functional behavior is identical, but mechanical and routing compatibility is not maintained across packages.
TL1431CLPRE3 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL1431CLPRE3 FAQ
1.How can I place an order for TL1431CLPRE3 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431CLPRE3 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 TL1431CLPRE3 reliable?
The price and inventory of TL1431CLPRE3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431CLPRE3 is usually 5 days.
3.What payment methods are accepted for TL1431CLPRE3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431CLPRE3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431CLPRE3?
TL1431CLPRE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431CLPRE3 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 TL1431CLPRE3?
For technical support, including TL1431CLPRE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431CLPRE3 requirements.
6.How does Aetrix verify that TL1431CLPRE3 is sourced from the original manufacturer or authorized distributors?
All TL1431CLPRE3 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 TL1431CLPRE3 meets industry standards.
7.What is the process for return or replacement of TL1431CLPRE3?
All TL1431CLPRE3 units undergo pre-shipment inspection (PSI). If there is an issue with TL1431CLPRE3, 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 TL1431CLPRE3 part is unused and in its original packaging.
Return procedure for TL1431CLPRE3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431CLPRE3 Tags
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AZ431LBNTR-G1
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LM4041DIM3-ADJ/NOPB
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LM4040DIM3X-2.5/NOPB
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AZ431LANTR-G1
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