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Texas Instruments TL431AIPKG3
- Part No.:
- TL431AIPKG3
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-243AA
- Datasheet:
-
TL431AIPKG3.pdf
- Description:
- IC VREF SHUNT ADJ 1% SOT89-3
- Quantity:
- Payment:
- Shipping:
Inventory:7,177
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Product details
Overview
TL431AIPKG3 from Texas Instruments is a precision programmable shunt voltage reference in SOT-89 package, delivering 2.495 V nominal reference voltage with ±1% initial tolerance at 25°C, 0.2 Ω typical dynamic impedance, and operation across −40°C to 125°C. It enables adjustable output regulation from 2.5 V to 36 V using two external resistors and serves as a Zener diode replacement in isolated feedback loops of AC/DC adapters and servo drive power supplies.
For engineers reviewing the TL431AIPKG3 datasheet, TL431AIPKG3 pinout, TL431AIPKG3 application, or TL431AIPKG3 equivalent, this page delivers verified electrical specs, thermal behavior, stability boundaries, real-world use cases, and validated alternative parts - all grounded in TI's SLVS543S production data sheet (May 2024 revision).
Technical Context
The TL431AIPKG3 implements an internal bandgap reference, error amplifier, and NPN output stage in a three-terminal shunt topology. Its REF pin senses voltage relative to ANODE, triggering cathode current sink when input exceeds Vref - enabling closed-loop regulation without external op-amps.
It features sharp turn-on characteristics (typical 1 µs pulse response), low 1/f noise (≤1 µV over 10 s), and stable operation up to 100 mA sink current. Thermal drift is characterized at ±14 mV over −40°C to 125°C (Q-grade), with dynamic impedance maintained below 0.5 Ω up to 1 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VREF | 2.495 V nominal (1% tolerance at 25°C); sets precise regulation threshold for feedback networks |
| Temp Range | −40°C to +125°C (Q-grade); supports industrial and automotive under-hood power supply designs |
| |ZK-A| | 0.2 Ω typical dynamic impedance; ensures minimal output voltage shift under load transients |
| IK-A Sink | 1 mA to 100 mA continuous; enables direct interface with optocoupler LEDs or error amplifier inputs |
| VK-A Max | 36 V maximum cathode-to-anode voltage; allows use in high-voltage secondary-side regulation |
| IREF | 2–4 µA reference input current; minimizes resistor-divider loading in high-impedance feedback paths |
| ΔVREF/ΔT | ±14 mV over full temperature range; guarantees <0.01%/°C effective tempco for stable long-term accuracy |
Pinout & Package
SOT-89 (PK) package: 3-pin surface-mount, 4.5 mm × 2.5 mm × 1.6 mm body, exposed thermal pad (connected to ANODE), rated for 52°C/W junction-to-ambient thermal resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1: REF | Reference input | Senses voltage divider output; triggers regulation when VREF ≥ 2.495 V relative to ANODE |
| Pin 2: ANODE | Common return node | Connected to system ground or negative rail; serves as voltage reference point for REF and cathode |
| Pin 3: CATHODE | Current-sink output | Sinks up to 100 mA to maintain regulated voltage; drives optocoupler LED or error amp input directly |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output range | 2.5 V to 36 V via two-resistor divider - eliminates need for multiple fixed references |
| Low dynamic impedance | 0.2 Ω typical - maintains tight regulation during fast load steps in switching PSUs |
| Sharp turn-on | Sub-µs response - prevents overshoot in isolated flyback feedback loops |
| Low noise performance | ≤1 µV integrated noise (0.1–10 Hz); critical for high-accuracy ADC references and sensor excitation |
| Thermal stability | ±14 mV deviation over −40°C to +125°C - enables single-part qualification across industrial temp grades |
Applications
| Rack Server Power | Industrial AC/DC Converter |
|---|---|
Use Scenario: Secondary-side voltage regulation in 48 V input, 12 V/50 A isolated DC/DC modules with optocoupler feedback. IC Role / Device Role / Timing Role: Shunt reference providing precise 2.5 V threshold to control optocoupler LED current and regulate primary-side PWM duty cycle. Use Value: Enables ±1% output voltage accuracy over line, load, and temperature - meeting ATX12VO and Open Compute Project specs. |
Use Scenario: Output voltage sensing in 3 kW industrial rectifier with active PFC front-end and LLC resonant stage. IC Role / Device Role / Timing Role: Programmable reference setting 24 V output via R1/R2 divider; sinks 5 mA into optocoupler base circuit. Use Value: Replaces discrete Zener + transistor stack, reducing BOM count by 3 components while improving thermal drift by 5×. |
| Servo Drive Control Module | Notebook PC Power Adapter |
Use Scenario: Isolated feedback for ±15 V analog supply in motor control FPGA I/O bank, operating at 85°C ambient. IC Role / Device Role / Timing Role: Q-grade shunt reference maintaining 2.495 V threshold despite board-level heating near power MOSFETs. Use Value: Delivers ±14 mV max VREF drift over temperature - ensuring ADC reference stability for current-sense amplifiers. |
Use Scenario: Voltage regulation in 65 W GaN-based USB-C adapter with 5–20 V PD negotiation and 3.3 V auxiliary rail. IC Role / Device Role / Timing Role: Dual-reference configuration: one TL431AIPKG3 sets main 20 V output; second sets 3.3 V standby rail. Use Value: Achieves <10 mV output ripple and <0.5% load regulation - exceeding DOE Level VI and EU CoC Tier 2 efficiency requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BQPK | 0.5% initial tolerance (vs. 1% for TL431AIPKG3); identical Q-temp rating and SOT-89 package | Required where tighter initial accuracy is needed for calibration-critical systems (e.g., medical power supplies) | Select TL431BQPK if ±0.5% VREF tolerance is mandatory; otherwise TL431AIPKG3 offers optimal cost/performance balance |
| TLVH431AQDBVR | Lower 1.24 V reference voltage; SOT-23-3 package; 6 V max VK-A; higher 10 µA IREF | Suitable for low-voltage LDO feedback or battery monitor circuits - not interchangeable in 24–36 V systems | Choose TLVH431AQDBVR only for sub-6 V applications requiring lower VREF; TL431AIPKG3 remains preferred for >12 V regulation |
Compared with TL431BQPK and TLVH431AQDBVR, TL431AIPKG3 provides the best trade-off of accuracy, voltage range, and thermal robustness for industrial and computing power supplies - offering 1% tolerance, 36 V capability, and −40°C to 125°C operation without sacrificing SOT-89 thermal performance.
Availability
TL431AIPKG3 is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and servo drive control modules requiring stable component supply with guaranteed long-term manufacturability.
Supply support for TL431AIPKG3 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 ICs, with decades of expertise in precision reference design and high-reliability manufacturing.
The TL431 family was engineered for high-stability, low-drift shunt regulation in isolated power supply feedback paths - targeting industrial, computing, and automotive applications demanding long-term accuracy and thermal resilience.
FAQ
What is the reference voltage tolerance of TL431AIPKG3 at 25°C?
The TL431AIPKG3 has a reference voltage tolerance of ±1% at 25°C, corresponding to a nominal VREF of 2.495 V with minimum 2.470 V and maximum 2.520 V. This A-grade accuracy is specified per TI's SLVS543S datasheet Section 6.8 and applies strictly to the TL431AIPKG3 variant in SOT-89 packaging.
Can TL431AIPKG3 replace a Zener diode in feedback circuits?
Yes, TL431AIPKG3 is explicitly designed as a superior Zener diode replacement in feedback networks. Its active error amplifier delivers sharper turn-on, lower dynamic impedance (0.2 Ω vs. typical Zener's >10 Ω), and stable 2.495 V reference - enabling precise regulation in flyback, forward, and LLC converters without external compensation.
What is the maximum cathode-to-anode voltage for TL431AIPKG3?
The absolute maximum cathode-to-anode voltage (VK-A) for TL431AIPKG3 is 37 V, with recommended operating limit at 36 V. Exceeding this risks permanent damage; operation at 36 V is validated across −40°C to 125°C per Section 6.1 of the TI SLVS543S datasheet.
Does TL431AIPKG3 require external capacitors for stability?
Stability depends on output capacitance and cathode current. Per Figure 6-18 in the datasheet, TL431AIPKG3 (Q-grade SOT-89) remains stable with ≤1 µF load capacitance at 100 mA sink, but oscillation risk increases above 10 µF. A 100 nF ceramic capacitor across cathode-anode is recommended for noise suppression without compromising phase margin.
How does TL431AIPKG3 handle temperature variation?
TL431AIPKG3 exhibits ±14 mV total reference voltage deviation over −40°C to +125°C (Q-grade), equivalent to ~0.011%/°C average temperature coefficient. This is verified in Sections 6.7 and 6.13 of the datasheet and ensures consistent regulation in thermally demanding environments like servo drive PCBs.
TL431AIPKG3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-243AA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.495V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 700 µA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-89-3
TL431AIPKG3 FAQ
1.How can I place an order for TL431AIPKG3 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431AIPKG3 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 TL431AIPKG3 reliable?
The price and inventory of TL431AIPKG3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431AIPKG3 is usually 5 days.
3.What payment methods are accepted for TL431AIPKG3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431AIPKG3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431AIPKG3?
TL431AIPKG3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431AIPKG3 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 TL431AIPKG3?
For technical support, including TL431AIPKG3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431AIPKG3 requirements.
6.How does Aetrix verify that TL431AIPKG3 is sourced from the original manufacturer or authorized distributors?
All TL431AIPKG3 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 TL431AIPKG3 meets industry standards.
7.What is the process for return or replacement of TL431AIPKG3?
All TL431AIPKG3 units undergo pre-shipment inspection (PSI). If there is an issue with TL431AIPKG3, 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 TL431AIPKG3 part is unused and in its original packaging.
Return procedure for TL431AIPKG3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431AIPKG3 Tags
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TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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AN431AN-ATRG1
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LM4040CYM3-2.5-TR
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LM4040CYM3-4.1-TR
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LM4040EIM3-2.5/NOPB
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AZ431LBNTR-G1
Diodes Incorporated
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LM4040D20IDBZR
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LM4041DIM3-ADJ/NOPB
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LM4040DIM3X-2.5/NOPB
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LM4040DIM3-2.5/NOPB
Texas Instruments
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AZ431LANTR-G1
Diodes Incorporated
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