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Texas Instruments TL431CPK
- Part No.:
- TL431CPK
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-243AA
- Datasheet:
-
TL431CPK.pdf
- Description:
- IC VREF SHUNT ADJ 2.2% SOT89-3
- Quantity:
- Payment:
- Shipping:
Inventory:22,315
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Product details
Overview
TL431CPK from Texas Instruments is a precision programmable shunt voltage reference in SOT-89 package, delivering 2.495 V nominal reference voltage with ±0.5% initial tolerance (B grade), 0.2 Ω typical dynamic impedance, and operation across −40°C to 125°C. It replaces Zener diodes in feedback loops of isolated DC/DC converters, AC/DC power supplies, and servo drive control modules.
For engineers reviewing the TL431CPK datasheet, TL431CPK pinout, TL431CPK application, or TL431CPK equivalent, this page provides verified electrical specs, thermal performance data, stability boundary conditions, and real-world implementation guidance for high-reliability power regulation design.
Technical Context
The TL431CPK implements an internal error amplifier and NPN transistor output stage configured as a three-terminal adjustable shunt regulator. Its REF pin senses voltage relative to ANODE, enabling precise feedback control when paired with two external resistors to set output from 2.495 V to 36 V.
It features sharp turn-on characteristics, low 1–100 mA sink-current capability, and stable operation under varying load and temperature-validated by ≤14 mV total reference voltage drift over −40°C to 125°C (Q-grade) and ≤6 mV over 0°C to 70°C (C-grade).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V nominal (±0.5% at 25°C); sets accurate feedback threshold for closed-loop regulation |
| Output Impedance | 0.2 Ω typical; ensures minimal output voltage shift under load transients |
| Sink Current Range | 1 mA to 100 mA; supports direct interface with optocoupler LEDs and PWM controller feedback pins |
| Temperature Range | −40°C to +125°C (Q-grade); qualified for industrial and automotive power systems |
| Dynamic Impedance | 0.2–0.5 Ω (≤1 kHz); maintains regulation stability in switching power supply feedback paths |
| Reference Input Current | 2–4 µA; enables high-impedance resistor-divider networks without significant loading error |
| Off-State Cathode Current | 0.1–0.5 µA at 36 V; minimizes standby power loss in always-on regulation circuits |
Pinout & Package
SOT-89 package (3-pin, 4.5 mm × 2.5 mm body, 1.5 mm height) with exposed thermal pad for enhanced heat dissipation in power regulation applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REF | Reference input | Senses voltage divider output; triggers regulation when ≥2.495 V above ANODE |
| ANODE | Common return path | Connected to system ground or negative rail; defines reference potential for REF and CATHODE |
| CATHODE | Shunt current output | Sinks current to maintain regulated voltage; drives optocoupler LED or error amplifier input |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output range | 2.495 V to 36 V via two external resistors-enables single BOM part for multiple output voltages |
| Low temperature drift | ≤14 mV over −40°C to 125°C-ensures <0.05% output variation in wide-temperature industrial environments |
| Sharp turn-on characteristic | Fast response to reference threshold crossing-reduces regulation delay in transient-sensitive SMPS designs |
| Low output noise | Sub-20 µVRMS (0.1–10 Hz); avoids noise-induced jitter in precision feedback loops |
| High ESD robustness | ±2000 V HBM-supports handling in standard manufacturing without special ESD controls |
Applications
| Rack Server Power | Industrial AC/DC |
|---|---|
Use Scenario: Secondary-side voltage regulation in isolated 48 V–12 V DC/DC converters for telecom server PSUs. IC Role / Device Role / Timing Role: Shunt reference in optocoupler-coupled feedback loop to maintain tight output voltage accuracy. Use Value: Enables ±1% output regulation across line/load/temperature while supporting remote sensing and dynamic margining. |
Use Scenario: Output voltage setting and overvoltage protection in 3 kW industrial AC/DC front-end supplies. IC Role / Device Role / Timing Role: Precision reference for error amplifier in voltage-mode control architecture. Use Value: Delivers stable 2.495 V reference with <6 mV drift over 0°C–70°C, reducing calibration burden in factory test. |
| AC Inverter & VF Drives | Servo Drive Control Module |
Use Scenario: DC bus voltage monitoring and trip-point generation in 3-phase motor inverters. IC Role / Device Role / Timing Role: Adjustable shunt reference feeding comparator input for overvoltage lockout. Use Value: Programmable 2.495–36 V threshold allows single design reuse across 400 V and 690 V AC input platforms. |
Use Scenario: Isolated feedback for auxiliary 5 V/3.3 V bias rails powering gate drivers and position sensors. IC Role / Device Role / Timing Role: Primary-side shunt reference in flyback converter feedback network. Use Value: 0.2 Ω dynamic impedance ensures <10 mV output deviation during 1 A load steps, preserving sensor 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 B-grade tolerance and Q-temp rating, but smaller footprint and lower thermal mass | Better suited for space-constrained PCBs; requires derating above 60 mA due to higher RθJA (206°C/W vs 52°C/W) | Select TL431CDBZR only when board area is critical and thermal load remains ≤60 mA. |
| TLVH431AQDBVR | Lower 1.24 V reference voltage; 1% initial tolerance; operates down to 2.5 V cathode-anode differential | Enables regulation below 2.5 V outputs (e.g., 1.8 V, 2.5 V rails); not drop-in compatible for >2.5 V designs | Choose TLVH431AQDBVR only when designing sub-2.5 V regulated outputs or ultra-low-voltage systems. |
Compared with TL431CDBZR and TLVH431AQDBVR, TL431CPK offers superior thermal performance (52°C/W RθJA) and full 2.495–36 V adjustability-making it optimal for high-current, high-temperature industrial power applications where stability and power dissipation are critical.
Availability
TL431CPK is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC, and servo drive control module designs requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for TL431CPK 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 leader specializing in analog and embedded processing technologies, with decades of expertise in precision analog ICs and power management solutions.
The TL431 product line was designed specifically for high-accuracy, low-drift voltage regulation in isolated power supplies, feedback control systems, and safety-critical voltage monitoring applications.
FAQ
What is the reference voltage tolerance of TL431CPK at 25°C?
The TL431CPK has a ±0.5% initial reference voltage tolerance at 25°C (B grade), corresponding to a 2.495 V nominal value with a guaranteed range of 2.483 V to 2.507 V. This tight tolerance reduces need for post-production calibration in precision power supplies and enables consistent performance across production batches of TL431CPK units.
How does TL431CPK differ from standard TL431 variants in thermal performance?
The TL431CPK uses the SOT-89 package with RθJA = 52°C/W-significantly lower than SOT-23-3 (206°C/W) or SOIC-8 (97°C/W) variants. This allows TL431CPK to sustain up to 100 mA sink current at 125°C ambient without exceeding 150°C junction temperature, making it preferred for high-power industrial applications where thermal headroom is constrained.
Can TL431CPK be used in place of a Zener diode?
Yes, TL431CPK is explicitly designed as a precision replacement for Zener diodes in shunt regulation applications. Unlike passive Zeners, TL431CPK provides sharp turn-on, low dynamic impedance (0.2 Ω), adjustable output (2.495–36 V), and stable temperature behavior-enabling tighter regulation, reduced component count, and improved reliability in TL431CPK-based feedback networks.
What is the minimum cathode current required for TL431CPK to regulate properly?
The TL431CPK requires a minimum cathode current (Imin) of 0.4 mA to maintain regulation, verified across −40°C to 125°C. This low threshold enables use with high-value resistor dividers and low-power optocouplers, ensuring reliable startup and regulation even in low-quiescent-current designs using TL431CPK.
Does TL431CPK support operation in automotive temperature ranges?
Yes, TL431CPK is rated for operation from −40°C to +125°C (Q-grade), meeting extended temperature requirements for under-hood and industrial motor drive applications. Its reference voltage drift is limited to ≤14 mV over this full range, ensuring <0.56% output variation-well within AEC-Q100 Grade 1 ambient limits for automotive power systems.
TL431CPK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-243AA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.495V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±2.2%
- 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:
- Surface Mount
- Supplier Device Package:
- SOT-89-3
TL431CPK FAQ
1.How can I place an order for TL431CPK through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431CPK 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 TL431CPK reliable?
The price and inventory of TL431CPK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431CPK is usually 5 days.
3.What payment methods are accepted for TL431CPK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431CPK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431CPK?
TL431CPK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431CPK 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 TL431CPK?
For technical support, including TL431CPK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431CPK requirements.
6.How does Aetrix verify that TL431CPK is sourced from the original manufacturer or authorized distributors?
All TL431CPK 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 TL431CPK meets industry standards.
7.What is the process for return or replacement of TL431CPK?
All TL431CPK units undergo pre-shipment inspection (PSI). If there is an issue with TL431CPK, 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 TL431CPK part is unused and in its original packaging.
Return procedure for TL431CPK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431CPK Tags
-
TL431AIDBZR
Texas Instruments
-
TL431BQDBZR
Texas Instruments
-
AN431AN-ATRG1
Diodes Incorporated
-
LM4040CYM3-2.5-TR
Microchip Technology
-
LM4040CYM3-4.1-TR
Microchip Technology
-
LM4040EIM3-2.5/NOPB
Texas Instruments
-
AZ431LBNTR-G1
Diodes Incorporated
-
LM4040D20IDBZR
Texas Instruments
-
LM4041DIM3-ADJ/NOPB
Texas Instruments
-
LM4040DIM3X-2.5/NOPB
Texas Instruments
-
LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
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