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Texas Instruments TL431QPK
- Part No.:
- TL431QPK
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-243AA
- Datasheet:
-
TL431QPK.pdf
- Description:
- IC VREF SHUNT ADJ 2.2% SOT89-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,925
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Product details
Overview
TL431QPK 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), 14–34 mV total temperature drift over −40°C to +125°C, and 0.2 Ω dynamic impedance. It operates as an adjustable feedback element in isolated DC/DC converters and automotive power supplies.
For engineers reviewing the TL431QPK datasheet, TL431QPK pinout, TL431QPK application, or TL431QPK equivalent, this page provides verified electrical specs, thermal performance data, Q-temp automotive qualification details, and validated alternative options for high-reliability power regulation design.
Technical Context
The TL431QPK implements a three-terminal adjustable shunt regulator architecture with internal error amplifier, reference, and output transistor. Its sharp turn-on characteristic and low 0.2 Ω dynamic impedance enable stable closed-loop regulation across wide load and input variations.
Designed for automotive-grade operation, the TL431QPK is characterized from −40°C to +125°C (Q-temp grade) and supports sink-current capability from 1 mA to 100 mA. It replaces discrete Zener diodes in feedback networks where precision, stability, and temperature robustness are required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V nominal (2.483–2.507 V for B-grade at 25°C); sets precise feedback threshold in switching regulator loops. |
| Initial Tolerance | ±0.5% at 25°C (B-grade); enables tight output voltage regulation without post-production trimming. |
| Temp Range | −40°C to +125°C (Q-temp); qualified for under-hood automotive and industrial high-temp environments. |
| Temp Drift (VI(dev)) | 14–34 mV over full range; ensures ≤0.014%/°C typical drift for stable reference across operating envelope. |
| Dynamic Impedance | 0.2 Ω typical (≤0.5 Ω max); maintains low output perturbation during fast load transients in feedback paths. |
| Sink Current Range | 1 mA to 100 mA; supports direct interface with optocoupler LEDs and low-power control logic. |
| Output Noise | Low broadband noise (typ. <10 µVRMS over 0.1–10 Hz); minimizes jitter in sensitive feedback sensing. |
Pinout & Package
SOT-89 (PK) package: 3-pin surface-mount, 4.5 mm × 2.5 mm × 1.6 mm body, thermally enhanced tab connected to ANODE for improved heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REF | Reference Input | High-impedance (2–4 µA typical) threshold node; connects to resistor divider to set output voltage. |
| ANODE | Common Return | Ground reference point; internally tied to substrate and thermal pad; must be connected to system ground or left open per layout guidelines. |
| CATHODE | Shunt Output | Current-sinking output terminal; delivers regulated current to optocoupler or error amplifier in isolated topologies. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output Range | 2.5 V to 36 V via two external resistors - enables single-part flexibility across multiple supply rails. |
| Automotive-Qualified Temp Range | −40°C to +125°C operation - meets AEC-Q100 stress test requirements for engine control and ADAS power modules. |
| Low Dynamic Impedance | 0.2 Ω typical - suppresses feedback loop instability and improves transient response in SMPS designs. |
| Sharp Turn-On Characteristic | Sub-100 ns rise time - ensures clean, deterministic regulation onset critical for safety-critical power sequencing. |
| ESD Robustness | ±2000 V HBM - withstands handling and board-level ESD events without latch-up or parameter shift. |
Applications
| Isolated Flyback Converter Feedback | Automotive Battery Management System |
|---|---|
Use Scenario: Regulates 12 V output in 48 V–12 V isolated flyback converter for vehicle infotainment head units. IC Role / Device Role / Timing Role: Shunt reference providing precise error signal to optocoupler-driven primary-side controller. Use Value: Enables ±1% output accuracy over temperature and line variation without secondary-side sensing circuitry. |
Use Scenario: Monitors cell stack voltage in 12S Li-ion battery pack for electric power steering (EPS). IC Role / Device Role / Timing Role: Precision voltage threshold detector feeding into microcontroller ADC reference path. Use Value: Delivers stable 2.495 V reference for 12-bit ADC measurements across −40°C to +125°C ambient. |
| Industrial AC/DC Power Supply | Servo Drive Control Module |
Use Scenario: Sets regulated 5 V auxiliary rail in DIN-rail mounted 240 VAC input power supply for PLC I/O modules. IC Role / Device Role / Timing Role: Programmable shunt regulator in secondary-side feedback network of LLC resonant converter. Use Value: Maintains 0.2 Ω impedance to prevent loop oscillation under 10–100 mA load steps at 50 kHz switching frequency. |
Use Scenario: Provides stable reference for current-sense amplifier offset calibration in 3-phase motor drive inverter. IC Role / Device Role / Timing Role: Low-noise, low-drift voltage source for analog front-end biasing in real-time torque control loop. Use Value: Limits reference-induced error to <0.02% of full-scale current measurement across full operating temperature range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BQDBZR | SOT-23-3 package (smaller footprint, lower thermal mass); identical electrical specs and Q-temp rating. | Better suited for space-constrained PCBs; requires re-evaluation of thermal derating due to higher RθJA (206°C/W vs. 52°C/W). | Select when board area is critical and thermal load remains ≤150 mW; verify layout cooling for sustained 100 mA sink. |
| TLVH431AQDBVR | Lower 1.24 V reference voltage; 1.5% initial tolerance; same Q-temp rating and SOT-23-5 package. | Enables lower-voltage feedback schemes (e.g., 3.3 V or 2.5 V rails); not interchangeable for 2.5 V+ setpoints without resistor recalculations. | Choose when designing sub-2.5 V regulated outputs or needing reduced reference headroom in low-input applications. |
Compared with TL431QPK, TL431BQDBZR offers identical performance in a smaller package but demands stricter thermal management, while TLVH431AQDBVR shifts the reference baseline downward-requiring redesign of feedback dividers but enabling new low-voltage architectures.
Availability
TL431QPK is available at Aetrix Electronics and suitable for automotive power modules, industrial AC/DC supplies, and servo drive control requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for TL431QPK 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 automotive and industrial qualification expertise.
The TL431 product line delivers precision programmable shunt references for feedback regulation in isolated and non-isolated power converters, emphasizing thermal stability, low noise, and automotive-grade reliability.
FAQ
What is the reference voltage tolerance of TL431QPK at 25°C?
The TL431QPK has a ±0.5% initial reference voltage tolerance at 25°C (B-grade specification), corresponding to a 2.483 V to 2.507 V range. This tight tolerance is confirmed in Section 6.13 of the TI SLVS543S datasheet and enables high-accuracy output regulation without external trimming. The TL431QPK maintains this spec across its full −40°C to +125°C operating range.
Does TL431QPK support operation above 100°C ambient?
Yes, TL431QPK is explicitly characterized for operation from −40°C to +125°C (Q-temp grade), making it suitable for under-hood automotive and high-temperature industrial environments. Its thermal resistance (RθJA = 52°C/W) and maximum junction temperature (150°C) allow continuous operation at 125°C ambient when power dissipation remains within derated limits - verified in TI's Thermal Information table (Section 6.3).
What is the dynamic impedance of TL431QPK and why does it matter?
The TL431QPK exhibits 0.2 Ω typical dynamic impedance (|ZKA|) at frequencies ≤1 kHz and cathode currents from 1 mA to 100 mA. This low value directly determines feedback loop stability and transient response in switching regulators - lower impedance reduces gain peaking and prevents oscillation when driving capacitive loads like optocoupler LEDs. Data is specified in Sections 6.5–6.13 of the datasheet.
Can TL431QPK replace a standard Zener diode in feedback circuits?
Yes, TL431QPK is engineered as a precision replacement for Zener diodes in feedback networks, offering sharper turn-on, lower dynamic impedance (0.2 Ω vs. typical 10–100 Ω for Zeners), and tighter voltage tolerance (±0.5% vs. ±5% for most Zeners). Its three-terminal architecture allows adjustable output from 2.5 V to 36 V using only two resistors - a capability standard Zeners lack. This is confirmed in the device description (Section 3).
What package type is used for TL431QPK and how does it affect thermal performance?
TL431QPK uses the SOT-89 (PK) package - a 3-pin surface-mount outline with an exposed thermal pad tied to the ANODE pin. Its RθJA is 52°C/W, significantly lower than SOT-23 variants (206°C/W), enabling higher continuous sink current (up to 100 mA) without exceeding 150°C junction temperature. Package dimensions and thermal metrics are documented in Section 6.3 and Mechanical Information (Section 12) of the datasheet.
TL431QPK 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 ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-89-3
TL431QPK FAQ
1.How can I place an order for TL431QPK through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431QPK 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 TL431QPK reliable?
The price and inventory of TL431QPK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431QPK is usually 5 days.
3.What payment methods are accepted for TL431QPK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431QPK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431QPK?
TL431QPK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431QPK 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 TL431QPK?
For technical support, including TL431QPK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431QPK requirements.
6.How does Aetrix verify that TL431QPK is sourced from the original manufacturer or authorized distributors?
All TL431QPK 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 TL431QPK meets industry standards.
7.What is the process for return or replacement of TL431QPK?
All TL431QPK units undergo pre-shipment inspection (PSI). If there is an issue with TL431QPK, 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 TL431QPK part is unused and in its original packaging.
Return procedure for TL431QPK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431QPK 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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