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Texas Instruments TL1431CLPR
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- Part No.:
- TL1431CLPR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
TL1431CLPR.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,990
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Product details
Overview
TL1431CLPR from Texas Instruments is a precision programmable shunt voltage reference IC with 0.4% initial voltage tolerance, 0.2Ω typical output impedance, and adjustable output voltage from 2.5V to 36V via two external resistors. It operates as a Zener replacement or error amplifier in secondary-side regulation of flyback SMPSs, delivering fast 500ns turnon and sink current capability from 1mA to 100mA.
For engineers reviewing the TL1431CLPR datasheet, TL1431CLPR pinout, TL1431CLPR application, or TL1431CLPR equivalent, this device serves as a thermally stable, externally programmable reference for onboard regulation, voltage monitoring, and comparator circuits requiring high accuracy across commercial temperature range (0°C to 70°C).
Technical Context
The TL1431CLPR integrates an internal 2.5V bandgap reference and high-gain transconductance amplifier driving a Darlington output stage. Its closed-loop operation enables precise voltage regulation by comparing the REF pin voltage against the internal reference and sinking cathode current to maintain equilibrium.
In open-loop mode, it functions as a comparator with integrated reference; in closed-loop configuration with resistive feedback between CATHODE and REF, it achieves stable shunt regulation without mandatory external compensation. Thermal drift is specified at ±20mV over 0°C to 70°C, and cathode voltage sensitivity to supply variation is –1.1 to –2 mV/V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V ±10 mV at 25°C; sets base point for programmable output |
| Initial Tolerance | ±0.4% at 25°C; ensures ≤10 mV absolute error in reference setting |
| Output Impedance | 0.2 Ω typical; minimizes load-induced voltage droop under 1–100 mA sink |
| Cathode Voltage Range | 2.5 V to 36 V; supports wide-range adjustable regulation without external op-amp |
| Sink Current Range | 1 mA to 100 mA; enables direct interface with optocoupler LEDs or error amplifier outputs |
| Reference Input Current | 1.5–2.5 µA at 25°C; low bias current reduces resistor-divider power loss and error |
| Turnon Time | 500 ns; supports fast transient response in clamp and protection circuits |
Pinout & Package
TL1431CLPR is supplied in TO-92 package (3-pin, 4.83 mm × 3.68 mm body), with pin 1 = CATHODE, pin 2 = ANODE, pin 3 = REF. ANODE is internally connected to ground reference; CATHODE sinks regulated current; REF senses feedback voltage.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Current-sink output | Primary regulation node - sinks current to maintain programmed voltage at REF |
| ANODE (Pin 2) | Ground reference / common return | Internal connection point for all circuit references; must be tied to system ground or lowest potential |
| REF (Pin 3) | Feedback input | Senses divided output voltage; forces CATHODE–ANODE voltage to 2.5V when closed-loop conditions are met |
Key Features
| Feature | Design Value |
|---|---|
| Programmable output voltage | 2.5 V to 36 V using two external resistors - eliminates need for multiple fixed-voltage references |
| Low output impedance | 0.2 Ω typical - maintains regulation accuracy under varying load currents up to 100 mA |
| Fast turnon response | 500 ns - enables use in overvoltage clamping and dynamic protection circuits |
| Thermal stability | ±20 mV over 0°C to 70°C - ensures consistent performance in commercial ambient environments |
| Zener diode replacement | No minimum current requirement beyond 1 mA - simplifies design vs. traditional Zeners needing ≥5 mA |
Applications
| Secondary-Side SMPS Regulation | Voltage Monitoring & Clamping |
|---|---|
Use Scenario: Isolated flyback converter where primary-side controller lacks direct output sensing. IC Role / Device Role / Timing Role: Shunt regulator providing feedback signal to optocoupler LED, enabling precise output voltage control across isolation barrier. Use Value: Enables ±1% output regulation without primary-side sensing components; leverages 0.4% reference tolerance and low output impedance for minimal loop error. |
Use Scenario: Overvoltage protection circuit on 12 V or 24 V rail in industrial control systems. IC Role / Device Role / Timing Role: Precision clamp - triggers at exact threshold (e.g., 12.5 V) using resistor divider on REF pin. Use Value: Replaces discrete Zener + transistor with single IC offering tighter tolerance (0.4% vs. 5%), lower leakage (<0.5 µA off-state), and faster response (500 ns). |
| Adjustable Linear Regulator Reference | Comparator with Integrated Reference |
Use Scenario: Programmable bench power supply requiring user-selectable output from 3 V to 30 V. IC Role / Device Role / Timing Role: Adjustable reference source for op-amp-based series pass regulator control loop. Use Value: Eliminates need for DAC or potentiometer-based reference; achieves 0.4% initial accuracy and <20 mV tempco over full range. |
Use Scenario: Battery voltage monitor in automotive accessory module detecting undervoltage (e.g., <11.8 V). IC Role / Device Role / Timing Role: Comparator with built-in 2.5 V reference - compares scaled battery voltage against REF pin. Use Value: Reduces BOM count by integrating reference and comparator function; avoids external reference drift and matching errors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar programmable shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBVR | Same 2.5 V reference, 0.4% tolerance, but SOIC-8 package; higher thermal resistance (114.7°C/W vs. TO-92's 157°C/W) | Preferred for PCB space-constrained designs with reflow assembly; less suitable for through-hole or high-ambient-temp chassis mounting | Select when automated assembly and board density outweigh thermal or mechanical mounting requirements |
| LM431ACM/NOPB | 1% initial tolerance (vs. 0.4%), wider VI(dev) (±50 mV over 0°C–70°C), higher II(ref) (max 4 µA) | Acceptable for cost-sensitive, non-critical regulation where ±1% output accuracy suffices | Choose only if budget constraints dominate and tighter reference accuracy is not required |
Compared with TL431CDBVR, TL1431CLPR offers identical electrical specs but superior mechanical fit for legacy through-hole layouts; versus LM431ACM/NOPB, TL1431CLPR delivers 2.5× tighter initial tolerance and lower reference current - critical for high-accuracy, low-power sensing.
Availability
TL1431CLPR is available at Aetrix Electronics and suitable for secondary-side SMPS regulation, voltage monitoring, adjustable linear regulators, and comparator circuits requiring stable component supply with guaranteed commercial-temperature-grade performance.
Supply support for TL1431CLPR 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 specializing in analog and embedded processing technologies, with leadership in precision analog ICs and power management solutions.
The TL1431 product line delivers programmable shunt references designed for high-accuracy voltage regulation and feedback in isolated power supplies, industrial controls, and test equipment - emphasizing thermal stability, low output impedance, and ease of implementation.
FAQ
What is the operating temperature range for TL1431CLPR?
The TL1431CLPR is characterized for operation from 0°C to 70°C - the commercial temperature grade. Its reference voltage deviation is specified at ±20 mV across this range, and it maintains 0.4% initial tolerance at 25°C. This makes TL1431CLPR suitable for indoor industrial, telecom, and computing applications where ambient temperatures remain within standard commercial limits.
Can TL1431CLPR replace a Zener diode directly?
Yes, TL1431CLPR can directly replace Zener diodes in shunt regulation applications. Unlike standard Zeners, TL1431CLPR provides 0.4% initial tolerance, 0.2Ω output impedance, and programmable voltage (2.5V–36V) using two resistors. It requires only ≥1 mA cathode current to regulate - lower than most Zeners - and exhibits sharper turnon (500ns), making TL1431CLPR a higher-precision, more flexible Zener replacement.
What is the minimum cathode current needed for regulation in TL1431CLPR?
The TL1431CLPR requires a minimum cathode current of 0.45 mA (typical) to 1 mA (max) at 25°C to enter and maintain regulation. Below this threshold, the internal amplifier cannot sustain closed-loop operation, and the REF pin voltage will not be held at 2.5 V. Designers must ensure external biasing - e.g., via RSUP - delivers sufficient current under worst-case load and input conditions to keep TL1431CLPR active.
How does TL1431CLPR achieve stability without an output capacitor?
TL1431CLPR is internally compensated for unity-gain stability with no external capacitor required between CATHODE and ANODE. Its architecture uses dominant-pole compensation within the transconductance amplifier stage, allowing stable operation across its full 1–100 mA sink range. However, if downstream circuitry introduces capacitive loading (e.g., optocoupler CTR variation), designers should consult Figure 5-12 in the datasheet to avoid oscillation - TL1431CLPR itself remains stable without added capacitance.
What package type is used for TL1431CLPR?
TL1431CLPR uses the TO-92 package - a 3-pin through-hole plastic case measuring 4.83 mm × 3.68 mm. Pin 1 is CATHODE, Pin 2 is ANODE (internally grounded), and Pin 3 is REF. This package supports manual assembly, prototyping, and chassis-mounted thermal dissipation - distinct from surface-mount variants like TL1431D (SOIC-8) or TL1431PW (TSSOP-8).
TL1431CLPR 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:
- Active
- 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
TL1431CLPR FAQ
1.How can I place an order for TL1431CLPR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431CLPR 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 TL1431CLPR reliable?
The price and inventory of TL1431CLPR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431CLPR is usually 5 days.
3.What payment methods are accepted for TL1431CLPR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431CLPR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431CLPR?
TL1431CLPR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431CLPR 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 TL1431CLPR?
For technical support, including TL1431CLPR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431CLPR requirements.
6.How does Aetrix verify that TL1431CLPR is sourced from the original manufacturer or authorized distributors?
All TL1431CLPR 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 TL1431CLPR meets industry standards.
7.What is the process for return or replacement of TL1431CLPR?
All TL1431CLPR units undergo pre-shipment inspection (PSI). If there is an issue with TL1431CLPR, 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 TL1431CLPR part is unused and in its original packaging.
Return procedure for TL1431CLPR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431CLPR Tags
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