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Texas Instruments TL431AQPK
- Part No.:
- TL431AQPK
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-243AA
- Datasheet:
-
TL431AQPK.pdf
- Description:
- IC VREF SHUNT ADJ 1% SOT89-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,883
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Product details
Overview
TL431AQPK from Texas Instruments is a precision programmable shunt voltage reference in SOT-89 package, delivering 2.47–2.52 V reference voltage (1% initial tolerance at 25°C), −40°C to +125°C operating range, and 0.2 Ω typical dynamic impedance for stable feedback in isolated DC-DC converters and industrial power supplies.
For engineers reviewing the TL431AQPK datasheet, TL431AQPK pinout, TL431AQPK application, or TL431AQPK equivalent, key selection criteria include automotive-grade temperature stability (Q-grade), low cathode current requirement (0.4–0.7 mA min), and compatibility with adjustable output regulation from 2.5 V to 36 V in flyback and forward converter feedback loops.
Technical Context
The TL431AQPK implements an internal error amplifier and NPN transistor output stage configured as a three-terminal adjustable shunt regulator. Its reference input (REF) compares against an internal 2.495 V bandgap, driving cathode current sink up to 100 mA when REF exceeds threshold.
It operates in closed-loop feedback configurations where external resistor dividers set output voltage; thermal drift is limited to 14–34 mV over −40°C to +125°C, and dynamic impedance remains ≤0.5 Ω below 1 kHz-critical for maintaining loop stability in high-frequency switching regulators.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.47–2.52 V at 25°C (1% A-grade tolerance); sets precise feedback threshold for output regulation |
| Operating Temperature | −40°C to +125°C (Q-grade); qualified for under-hood automotive and industrial ambient environments |
| Dynamic Impedance | 0.2 Ω typical (≤0.5 Ω max); ensures minimal AC voltage deviation during load transients |
| Cathode Current Range | 0.4–0.7 mA minimum, up to 100 mA; enables operation with high-resistance feedback networks and robust sink capability |
| Reference Input Current | 2–4 µA typical; imposes negligible loading on resistive divider, preserving accuracy |
| Output Voltage Range | Adjustable from 2.5 V to 36 V via two external resistors; supports wide-range SMPS designs |
| Tempco (VI(dev)) | 14–34 mV total deviation over full temperature range; guarantees <±2.7 mV/V line regulation sensitivity |
Pinout & Package
SOT-89 package (3-pin, 4.5 mm × 2.5 mm × 1.6 mm body), thermally enhanced with exposed tab connected to ANODE for PCB heat sinking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REF (Pin 1) | Reference input | High-impedance comparator input tied to internal 2.495 V bandgap; connects to resistor divider midpoint |
| ANODE (Pin 2) | Common return | Internal substrate connection; must be tied to system ground or low-impedance return path for stable regulation |
| CATHODE (Pin 3) | Current sink output | Drives optocoupler LED or error amplifier in isolated feedback; sinks up to 100 mA with <0.5 Ω effective impedance |
Key Features
| Feature | Design Value |
|---|---|
| Automotive-Qualified Temp Range | −40°C to +125°C operation (Q-grade), meeting AEC-Q100 stress test requirements for under-hood use |
| Low Dynamic Impedance | 0.2 Ω typical ensures <1 mV output perturbation under 10 mA AC load steps-critical for tight-regulation SMPS |
| Sharp Turn-On Characteristic | Sub-100 ns response to REF threshold crossing enables fast correction in high-bandwidth feedback loops |
| Low Reference Input Current | 2–4 µA allows use of >1 MΩ feedback resistors without significant divider error or bias-induced drift |
| Wide Cathode Voltage Range | Supports VKA = Vref to 36 V, enabling direct interface with 24 V industrial rails and 48 V telecom systems |
Applications
| Rack Server Power Supply | Industrial AC/DC Converter |
|---|---|
Use Scenario: Secondary-side voltage sensing in isolated 48 V–12 V DC-DC modules with optocoupler feedback. IC Role / Device Role / Timing Role: Shunt reference providing precise 2.5 V threshold to drive optocoupler LED current proportional to output error. Use Value: Enables ±1% output regulation across line/load/temperature with <0.5 Ω dynamic impedance minimizing feedback loop phase shift. |
Use Scenario: Output voltage regulation in 3-phase rectifier-based 24 V industrial power supply with wide input variation. IC Role / Device Role / Timing Role: Adjustable shunt reference setting regulated 24 V output via 10 kΩ/10 kΩ resistor divider. Use Value: 1% initial accuracy and 14–34 mV tempco ensure stable output despite ambient swings from −25°C to +75°C cabinet temperatures. |
| AC Inverter Drive Control | Servo Drive Feedback Loop |
Use Scenario: DC bus voltage monitoring and overvoltage protection trigger in 400 V AC inverter front-end. IC Role / Device Role / Timing Role: Precision reference feeding comparator that asserts fault signal when bus exceeds 420 V threshold. Use Value: 2.5 V reference accuracy combined with external resistor scaling yields <0.5% OV trip tolerance, improving system safety margin. |
Use Scenario: Isolated current-sense amplifier reference in motor phase current feedback path of servo drive. IC Role / Device Role / Timing Role: Stable 2.5 V reference for delta-sigma ADC biasing and analog front-end offset calibration. Use Value: Low 2–4 µA input current prevents loading of high-impedance sense resistor networks, preserving measurement linearity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACPK | 1% tolerance, 0°C to 70°C rating (C-grade), same SOT-89 package and pinout | Limited to commercial-temperature environments; unsuitable for under-hood or uncooled industrial enclosures | Select TL431ACPK only for cost-sensitive non-automotive applications where ambient stays within 0–70°C. |
| TL431BQPK | 0.5% tolerance (B-grade), identical Q-temp rating and SOT-89 package | Higher initial accuracy enables tighter output regulation (±0.5% vs ±1%) without recalculating feedback resistors | Choose TL431BQPK when system-level output tolerance budget requires <±0.75% total error including resistor drift and tempco. |
Compared with TL431AQPK, TL431ACPK sacrifices temperature range for lower cost, while TL431BQPK improves initial accuracy by 0.5% without changing layout or thermal design-making it ideal for high-precision industrial power modules requiring long-term stability.
Availability
TL431AQPK is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and AC inverter drive control requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for TL431AQPK 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 and power control technologies.
The TL431 product line delivers pin-compatible, grade-scaled programmable shunt references optimized for feedback accuracy, thermal stability, and reliability in isolated switch-mode power supplies across automotive, industrial, and computing markets.
FAQ
What is the reference voltage tolerance of TL431AQPK at 25°C?
The TL431AQPK has a reference voltage tolerance of ±1% at 25°C, corresponding to a 2.47–2.52 V range. This A-grade specification is confirmed in Section 6.10 of the TI SLVS543S datasheet and applies specifically to the Q-temp variant in PK package. The TL431AQPK maintains this tolerance across its full −40°C to +125°C operating range with defined drift limits.
Does TL431AQPK support operation above 85°C?
Yes, TL431AQPK is rated for continuous operation from −40°C to +125°C (Q-grade). Its electrical characteristics-including reference voltage, dynamic impedance, and cathode current-are fully specified across this extended range per Section 6.7 and 6.10 of the datasheet. This makes TL431AQPK suitable for under-hood automotive and high-ambient industrial applications where standard I-grade (−40°C to +85°C) devices would fail.
What is the minimum cathode current required for regulation in TL431AQPK?
The TL431AQPK requires a minimum cathode current of 0.4–0.7 mA to maintain regulation, as specified in Section 6.10 (Imin parameter). This value is higher than the C-grade version due to Q-temp process characterization but remains compatible with standard 10 kΩ–100 kΩ feedback dividers. Below this threshold, the device exits regulation and cathode voltage rises toward VKA.
Can TL431AQPK replace a Zener diode in feedback circuits?
Yes, TL431AQPK is explicitly designed as a superior replacement for Zener diodes in voltage regulation feedback paths. Its 0.2 Ω dynamic impedance, sharp turn-on, and 1% initial accuracy provide significantly better line/load regulation and temperature stability than discrete Zeners. TI's datasheet confirms TL431AQPK usage in on-board regulation, adjustable power supplies, and switching power supplies-directly replacing Zener-based solutions.
What package type does TL431AQPK use and how is thermal performance characterized?
TL431AQPK uses the SOT-89 (PK) package with three leads and an exposed thermal tab connected to the ANODE pin. Its thermal resistance is characterized as RθJA = 52°C/W and RθJC(top) = 9°C/W (Section 6.3), enabling effective PCB heat sinking when the tab is soldered to a copper pour. This thermal performance supports continuous 100 mA cathode current dissipation in compact industrial power designs.
TL431AQPK 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:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 700 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-89-3
TL431AQPK FAQ
1.How can I place an order for TL431AQPK through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431AQPK 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 TL431AQPK reliable?
The price and inventory of TL431AQPK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431AQPK is usually 5 days.
3.What payment methods are accepted for TL431AQPK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431AQPK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431AQPK?
TL431AQPK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431AQPK 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 TL431AQPK?
For technical support, including TL431AQPK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431AQPK requirements.
6.How does Aetrix verify that TL431AQPK is sourced from the original manufacturer or authorized distributors?
All TL431AQPK 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 TL431AQPK meets industry standards.
7.What is the process for return or replacement of TL431AQPK?
All TL431AQPK units undergo pre-shipment inspection (PSI). If there is an issue with TL431AQPK, 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 TL431AQPK part is unused and in its original packaging.
Return procedure for TL431AQPK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431AQPK 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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