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Texas Instruments TL431IPK
- Part No.:
- TL431IPK
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-243AA
- Datasheet:
-
TL431IPK.pdf
- Description:
- IC VREF SHUNT ADJ 2.2% SOT89-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,030
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Product details
Overview
TL431IPK 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 adapters, and industrial servo drive power supplies.
For engineers reviewing the TL431IPK datasheet, TL431IPK pinout, TL431IPK application, or TL431IPK equivalent, this page delivers verified electrical specs, thermal performance data, stability boundary conditions, and real-world implementation guidance for high-reliability power regulation design.
Technical Context
The TL431IPK implements an internal error amplifier and NPN transistor output stage configured as an adjustable shunt regulator. Its REF pin senses voltage relative to ANODE, enabling precise feedback control when paired with two external resistors - setting 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 conditions. The SOT-89 package provides enhanced thermal dissipation (RθJA = 52°C/W) critical for high-current regulation in compact industrial power modules.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V ±0.5% at 25°C - enables accurate feedback setpoint for ±1% output regulation in switching PSUs. |
| Operating Temperature | −40°C to +125°C - qualified for automotive-grade and industrial motor drive environments. |
| Dynamic Impedance | 0.2 Ω typical - ensures minimal output voltage deviation under fast load transients (e.g., servo current spikes). |
| Sink Current Range | 1 mA to 100 mA - supports direct interface with optocoupler LEDs in isolated flyback controllers without external buffering. |
| Temperature Drift | ≤14 mV over full range - maintains <±0.6% reference stability across operating temperature, critical for precision ADC references. |
| Output Noise | Low broadband noise - avoids injection of switching artifacts into sensitive analog control paths. |
| Input Bias Current | 2–4 µA - permits use with high-value feedback resistors (>1 MΩ), reducing power loss in battery-powered systems. |
Pinout & Package
SOT-89 package (3-pin, 4.5 mm × 2.5 mm × 1.6 mm body), thermally optimized with exposed tab connected to ANODE for PCB heat sinking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REF | Reference input | Senses voltage divider output; threshold comparator input referenced to internal 2.495 V bandgap. |
| ANODE | Common return node | Connected to system ground or negative rail; also serves as thermal path via exposed pad. |
| CATHODE | Shunt current output | Sinks regulated current to maintain REF voltage; drives optocoupler LED or pass transistor base in feedback loop. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output range | 2.495 V to 36 V - achieved with only two external resistors, eliminating need for multiple fixed-voltage references. |
| Sharp turn-on characteristic | Fast response to REF voltage deviations - enables stable closed-loop regulation in high-bandwidth SMPS designs. |
| Low output impedance | 0.2 Ω typical - minimizes interaction with downstream capacitive loads and improves PSRR in LDO-like configurations. |
| Thermal stability | ≤14 mV drift over −40°C to +125°C - ensures consistent regulation accuracy without external compensation. |
| High ESD robustness | ±2000 V HBM - withstands handling and board-level ESD events common in industrial assembly environments. |
Applications
| Rack Server Power Supply | Industrial AC/DC Converter |
|---|---|
Use Scenario: Secondary-side voltage regulation in isolated 48 V input, 12 V/50 A telecom rectifier modules. IC Role / Device Role / Timing Role: Shunt reference in optocoupler-coupled feedback loop controlling primary-side PWM duty cycle. Use Value: Enables ±1% output accuracy across line/load/temperature while supporting fast transient recovery (<10 µs) during CPU burst loads. |
Use Scenario: Output voltage sensing in 3 kW industrial AC/DC front-end supplying PLC I/O modules. IC Role / Device Role / Timing Role: Precision reference for isolated error amplifier driving gate driver IC in LLC resonant converter. Use Value: Maintains tight regulation (±0.5%) over 40–85°C ambient with no calibration, reducing BOM count vs. trimmed references. |
| AC Inverter Drive | Servo Drive Control Module |
Use Scenario: DC bus voltage monitoring and overvoltage protection trigger in 7.5 kW variable-frequency drive. IC Role / Device Role / Timing Role: Adjustable threshold detector feeding comparator input for fast shutdown logic. Use Value: Programmable trip point (e.g., 780 V) with <±2 V tolerance eliminates need for discrete resistor networks and trimming. |
Use Scenario: Reference source for current-sense amplifier offset nulling and DAC-based torque command scaling. IC Role / Device Role / Timing Role: Stable 2.495 V bias for precision instrumentation amplifiers in motor phase current measurement path. Use Value: Low drift ensures <±0.1% gain error contribution over motor thermal cycling, improving torque linearity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CPK | Same SOT-89 package but C-temp grade (0°C to 70°C) and ±2% initial tolerance. | Limited to commercial-temperature applications like consumer adapters; unsuitable for industrial enclosures. | Select TL431CPK only if cost sensitivity outweighs temperature range and accuracy requirements. |
| TL431BIDBZR | SOT-23-3 package, same B-grade accuracy and Q-temp rating, but lower thermal mass and RθJA = 206°C/W. | Better suited for space-constrained, low-power applications (e.g., IoT sensor nodes); not recommended above 25 mA continuous sink. | Choose TL431BIDBZR when PCB area is critical and thermal load is ≤150 mW; otherwise retain TL431IPK for higher power density. |
Compared with TL431CPK and TL431BIDBZR, the TL431IPK uniquely balances wide temperature operation (−40°C to +125°C), high-accuracy B-grade tolerance (±0.5%), and robust thermal performance (52°C/W) - making it the preferred choice for industrial motor drives and telecom power systems requiring long-term stability under thermal stress.
Availability
TL431IPK is available at Aetrix Electronics and suitable for rack server power supplies, industrial AC/DC converters, and servo drive control modules requiring stable component supply with guaranteed long-term manufacturability.
Supply support for TL431IPK 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, embedded processing, and power management technologies, with decades of experience in precision reference design.
The TL431 product line was engineered for high-stability, low-drift voltage regulation in safety-critical power conversion systems - targeting industrial automation, telecom infrastructure, and automotive subsystems.
FAQ
What is the maximum cathode voltage rating for TL431IPK?
The TL431IPK has an absolute maximum cathode-to-anode voltage (VKA) of 37 V. Operation up to 36 V is supported under recommended conditions. Exceeding 37 V risks permanent damage. This rating allows safe use in 24 V and 36 V industrial bus systems with margin for transient spikes.
Can TL431IPK replace a Zener diode directly in existing designs?
Yes, TL431IPK can directly replace Zener diodes in shunt regulator configurations, provided the external resistor network sets the desired output voltage and the sink current remains within 1–100 mA. Its sharp turn-on and low dynamic impedance improve regulation accuracy and transient response beyond typical Zener performance.
Does TL431IPK require external compensation for stability?
TL431IPK does not require external compensation in most standard feedback configurations. However, stability depends on load capacitance and cathode current - Figure 6-18 in the datasheet defines oscillation boundaries. For >1 µF output capacitance or >50 mA sink current, verify phase margin using the provided test circuits.
What is the thermal resistance (RθJA) of TL431IPK in its SOT-89 package?
The TL431IPK in SOT-89 package has a junction-to-ambient thermal resistance (RθJA) of 52°C/W under standard JEDEC test conditions. With proper PCB copper pour under the exposed tab, actual thermal performance improves significantly - enabling reliable 100 mA operation at +85°C ambient.
How does the reference input current (Iref) of TL431IPK affect feedback resistor selection?
The TL431IPK reference input current is 2–4 µA at 25°C. To minimize voltage error from Iref, total feedback resistor sum should be ≤100 kΩ (e.g., 20 kΩ + 80 kΩ). Higher values increase offset error and temperature drift; lower values increase power loss. Designers commonly use 10–47 kΩ for optimal trade-off.
TL431IPK 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-89-3
TL431IPK FAQ
1.How can I place an order for TL431IPK through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431IPK 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 TL431IPK reliable?
The price and inventory of TL431IPK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431IPK is usually 5 days.
3.What payment methods are accepted for TL431IPK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431IPK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431IPK?
TL431IPK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431IPK 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 TL431IPK?
For technical support, including TL431IPK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431IPK requirements.
6.How does Aetrix verify that TL431IPK is sourced from the original manufacturer or authorized distributors?
All TL431IPK 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 TL431IPK meets industry standards.
7.What is the process for return or replacement of TL431IPK?
All TL431IPK units undergo pre-shipment inspection (PSI). If there is an issue with TL431IPK, 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 TL431IPK part is unused and in its original packaging.
Return procedure for TL431IPK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431IPK Tags
-
TL431AIDBZR
Texas Instruments
-
TL431BQDBZR
Texas Instruments
-
AN431AN-ATRG1
Diodes Incorporated
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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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