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Texas Instruments TL431CKTPR
- Part No.:
- TL431CKTPR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
TL431CKTPR.pdf
- Description:
- PRECISION SHUNT ADJUST REG TO252
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
TL431CKTPR from Texas Instruments is a precision programmable shunt voltage reference in PowerFLEX (TO-252) package, featuring 0.5% initial reference voltage tolerance at 25°C, adjustable output from 2.495 V to 36 V via two external resistors, and operation across −40°C to 125°C. It delivers 0.2 Ω typical dynamic impedance and sinks 1–100 mA cathode current, enabling Zener diode replacement in secondary-side regulation of flyback SMPSs.
For engineers reviewing the TL431CKTPR datasheet, TL431CKTPR pinout, TL431CKTPR application, or TL431CKTPR equivalent, this page provides verified electrical specifications, thermal performance data, validated alternative parts, and real-world implementation context for power supply feedback loop design, voltage monitoring, and adjustable referencing.
Technical Context
The TL431CKTPR implements an internal 2.495 V bandgap reference with high-gain error amplifier driving a NPN transistor output stage, configured as a three-terminal adjustable shunt regulator. Its sharp turn-on characteristic and low output impedance enable stable closed-loop regulation without external compensation in many applications.
It operates with cathode-to-anode voltage (VKA) from 2.495 V to 36 V and requires ≥0.4 mA minimum cathode current for regulation. The reference input current (Iref) remains ≤4 µA over temperature, minimizing resistor-divider loading error in precision voltage-setting networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Vref | 2.495 V ±0.5% at 25°C - sets precise feedback threshold for power supply control loops |
| VKA Range | 2.495 V to 36 V - supports wide-range adjustable output without external op-amp |
| IKA Sink | 1 mA to 100 mA - enables direct drive of optocoupler LEDs or small-signal loads |
| Dynamic Impedance | 0.2 Ω typical - ensures minimal output voltage deviation under load transients |
| Temp Drift (VI(dev)) | 14 mV max over −40°C to 125°C - maintains <0.05% output stability across automotive temp range |
| Iref | ≤4 µA - reduces divider resistor power loss and thermal drift in high-impedance networks |
| Package | PowerFLEX (TO-252) - thermally robust surface-mount package with 52°C/W junction-to-ambient rating |
Pinout & Package
TL431CKTPR uses the KTP (PowerFLEX / TO-252) package: 3-pin surface-mount outline with exposed thermal pad, nominal body size 6.5 mm × 6.1 mm × 2.3 mm, and ANODE pin electrically connected to the thermal pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REF | Reference input | High-impedance comparator input tied to internal 2.495 V bandgap; sets regulation point when voltage at this pin equals Vref |
| CATHODE | Shunt current output | Sinks current from external supply through feedback network; controls power stage via optocoupler or direct connection |
| ANODE | Common return | Connected to system ground or low-side return path; thermal pad must be soldered to PCB copper for thermal management |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% reference accuracy | Enables ±1% output voltage tolerance in isolated SMPS designs without trimming |
| 0.2 Ω dynamic impedance | Reduces output ripple sensitivity to cathode current variations in feedback paths |
| −40°C to 125°C operation | Supports under-hood automotive and industrial ambient environments without derating |
| Low 4 µA reference current | Permits use of >1 MΩ resistor dividers, lowering power consumption and self-heating error |
| Sharp turn-on characteristic | Eliminates need for external hysteresis in voltage monitor and battery protection circuits |
Applications
| Secondary-Side Regulation in Flyback SMPS | Zener Diode Replacement |
|---|---|
Use Scenario: Isolated DC-DC converter where primary-side controller receives feedback via optocoupler. IC Role / Device Role / Timing Role: Shunt regulator providing precise voltage reference to drive optocoupler LED, closing feedback loop across isolation barrier. Use Value: Enables ±1% output regulation with no primary-side sensing; 0.2 Ω impedance minimizes optocoupler current variation-induced errors. | Use Scenario: Low-power voltage clamping or reference generation in space-constrained PCBs. IC Role / Device Role / Timing Role: Adjustable shunt element replacing discrete Zener diodes with tighter tolerance and lower dynamic resistance. Use Value: Delivers 0.5% accuracy vs. typical 5% Zener tolerance; 0.2 Ω impedance improves regulation under varying load conditions. |
| Voltage Monitoring & Protection | Adjustable Current Reference |
Use Scenario: Overvoltage lockout circuit for Li-ion battery charging or DC bus supervision. IC Role / Device Role / Timing Role: Precision comparator with integrated reference detecting threshold crossings on monitored rail. Use Value: 14 mV max temp drift ensures reliable trip point across −40°C to 125°C; sharp turn-on prevents chatter near threshold. | Use Scenario: Constant-current source for LED biasing or sensor excitation. IC Role / Device Role / Timing Role: Shunt regulator configured with sense resistor to set precise current through load. Use Value: 4 µA Iref enables high-value sense resistors, reducing power loss; 0.5% Vref accuracy translates directly to current accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBZR | SOT-23-3 package; same 0.5% grade, but 206°C/W θJA vs. TL431CKTPR's 52°C/W | Lower power dissipation capability; suitable only for <150 mW applications | Select TL431CDBZR only for low-current, space-constrained designs where thermal mass is limited |
| TL431BQDBVR | Same PowerFLEX package, but B-grade (0.5%) + Q-temp (−40°C to 125°C); identical VI(dev) and thermal specs | No functional difference; identical performance envelope and pinout | TL431BQDBVR is a direct form-fit-function replacement with identical qualification for automotive use |
Compared with TL431CDBZR, TL431CKTPR offers 4× better thermal performance for high-current regulation; versus TL431BQDBVR, it shares identical specs but differs in ordering suffix-both meet AEC-Q100 Grade 1 requirements and support drop-in use in automotive power supplies.
Availability
TL431CKTPR is available at Aetrix Electronics and suitable for flyback SMPS design, voltage monitoring systems, and precision current reference circuits requiring stable component supply across automotive, industrial, and telecom power applications.
Supply support for TL431CKTPR 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 consumer markets.
The TL431 product line was designed as a precision programmable shunt reference for feedback loop stabilization in isolated switching power supplies and voltage supervision circuits, targeting high-reliability applications demanding tight initial tolerance and low temperature drift.
FAQ
What is the reference voltage tolerance of TL431CKTPR at 25°C?
The TL431CKTPR has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 2.495 V nominal output with a min/max range of 2.483 V to 2.507 V. This B-grade accuracy is confirmed in Section 7.11 of the SLVS543P datasheet and applies specifically to the CKTPR variant with PowerFLEX packaging and Q-temperature rating.
Can TL431CKTPR replace a Zener diode in a 12-V regulator circuit?
Yes, TL431CKTPR can directly replace Zener diodes in 12-V regulator circuits by configuring R1 and R2 to set VOUT = 12 V using the formula VOUT = Vref × (1 + R1/R2). Its 0.2 Ω dynamic impedance and 0.5% tolerance provide significantly tighter regulation than typical 5% Zener diodes, especially under varying load or temperature conditions.
What is the maximum cathode-to-anode voltage (VKA) for TL431CKTPR?
The absolute maximum cathode-to-anode voltage (VKA) for TL431CKTPR is 37 V, with recommended operating range from 2.495 V to 36 V. This limit is specified in Section 7.1 (Absolute Maximum Ratings) of the TI SLVS543P datasheet and applies across all temperature grades including the Q-temp variant used in TL431CKTPR.
Does TL431CKTPR require external compensation in feedback loops?
No, TL431CKTPR does not require external compensation in most standard feedback configurations due to its internally compensated error amplifier and sharp turn-on characteristic. Its 0.2 Ω dynamic impedance and stable phase margin allow direct use with optocouplers in flyback converters without added RC networks, as validated in TI Application Report SLVA614.
What is the thermal resistance (θJA) of TL431CKTPR in its PowerFLEX package?
The junction-to-ambient thermal resistance (θJA) of TL431CKTPR in the KTP (PowerFLEX/TO-252) package is 52°C/W, as specified in Table 7.3 of the SLVS543P datasheet. This value assumes standard JEDEC 2S2P board layout with 1-inch² copper pour connected to the exposed thermal pad.
TL431CKTPR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Reference Type:
- -
- Output Type:
- -
- Voltage - Output (Min/Fixed):
- -
- Voltage - Output (Max):
- -
- Current - Output:
- -
- Tolerance:
- -
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-252-3
TL431CKTPR FAQ
1.How can I place an order for TL431CKTPR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431CKTPR 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 TL431CKTPR reliable?
The price and inventory of TL431CKTPR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431CKTPR is usually 5 days.
3.What payment methods are accepted for TL431CKTPR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431CKTPR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431CKTPR?
TL431CKTPR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431CKTPR 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 TL431CKTPR?
For technical support, including TL431CKTPR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431CKTPR requirements.
6.How does Aetrix verify that TL431CKTPR is sourced from the original manufacturer or authorized distributors?
All TL431CKTPR 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 TL431CKTPR meets industry standards.
7.What is the process for return or replacement of TL431CKTPR?
All TL431CKTPR units undergo pre-shipment inspection (PSI). If there is an issue with TL431CKTPR, 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 TL431CKTPR part is unused and in its original packaging.
Return procedure for TL431CKTPR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431CKTPR Tags
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TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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AN431AN-ATRG1
Diodes Incorporated
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LM4040CYM3-2.5-TR
Microchip Technology
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LM4040CYM3-4.1-TR
Microchip Technology
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LM4040EIM3-2.5/NOPB
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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
-
AZ431LANTR-G1
Diodes Incorporated
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