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Texas Instruments TL431QDR
- Part No.:
- TL431QDR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431QDR.pdf
- Description:
- IC VREF SHUNT ADJ 2.2% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,383
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Product details
Overview
TL431QDR from Texas Instruments is a precision programmable shunt voltage reference in SOT-23-3 package, delivering 2.495 V nominal reference voltage with ±0.5% initial tolerance (B grade), −40°C to +125°C operating range, and 0.2 Ω typical dynamic impedance. It functions as an adjustable feedback element in isolated DC-DC converters, AC/DC power supplies, and industrial servo drive control modules.
For engineers reviewing the TL431QDR datasheet, TL431QDR pinout, TL431QDR application, or TL431QDR equivalent, key selection criteria include automotive-grade temperature stability (Q-temp), low output noise, sink-current capability up to 100 mA, and compatibility with standard resistor-divider programming for output voltages from 2.5 V to 36 V.
Technical Context
The TL431QDR implements a high-gain transconductance amplifier with internal 2.495 V bandgap reference, enabling precise regulation via external resistive feedback between cathode and reference terminals. Its sharp turn-on characteristic and low output impedance make it functionally superior to discrete Zener diodes in closed-loop feedback paths.
Designed for Q-temp (−40°C to +125°C) operation, the device exhibits 14 mV maximum reference voltage deviation over temperature and maintains stable regulation down to 0.4 mA minimum cathode current. It supports both fixed and adjustable output configurations without requiring external compensation in most power supply topologies.
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 for voltage regulation loops. |
| Initial Tolerance | ±0.5% at 25°C (B grade); enables tight output voltage accuracy without post-manufacturing trimming. |
| Temp Range | −40°C to +125°C (Q grade); qualified for under-hood automotive and industrial motor control environments. |
| Dynamic Impedance | 0.2 Ω typical; ensures minimal output voltage shift under load transients in feedback networks. |
| Sink Current Range | 1 mA to 100 mA; supports direct interface with optocoupler LEDs and error amplifiers in isolated PSUs. |
| Ref Input Current | 2–4 µA typical; allows use of high-value feedback resistors (>1 MΩ) to minimize power loss and thermal drift. |
| Output Noise | Low broadband noise; critical for low-noise LDOs and precision analog monitoring circuits. |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm body size), surface-mount, RoHS-compliant. Pin 1 = Cathode, Pin 2 = Reference, Pin 3 = Anode.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 1) | Shunt current input / regulated output node | Connects to primary-side feedback point in flyback converters; sinks current to maintain reference voltage at REF pin. |
| Reference (Pin 2) | High-impedance threshold input | Compares external divider voltage against internal 2.495 V reference; draws only 2–4 µA, enabling high-resistor-ratio designs. |
| Anode (Pin 3) | Common return / ground reference | Typically tied to system ground or power supply return; serves as voltage reference point for all internal circuitry. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output Range | 2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-reference parts across power rail variants. |
| Automotive-Qualified Temp Range | −40°C to +125°C operation - meets AEC-Q100 stress test requirements for engine control and battery management systems. |
| Low Dynamic Impedance | 0.2 Ω typical - minimizes output voltage droop during fast load steps in switching regulator feedback paths. |
| Sharp Turn-On Characteristic | Fast response with no external compensation required - simplifies design of stable optocoupler-based isolated feedback loops. |
| Low Reference Input Current | 2–4 µA typical - enables >1 MΩ feedback dividers, reducing self-heating and improving long-term voltage stability. |
Applications
| Rack Server Power Supply | Industrial AC/DC Converter |
|---|---|
Use Scenario: Secondary-side voltage regulation in 48 V input, 12 V/50 A isolated DC-DC modules with digital PMBus control. IC Role / Device Role / Timing Role: Precision shunt reference in optocoupler feedback loop, setting output voltage accuracy and transient response. Use Value: Enables ±1% output regulation over line, load, and temperature while supporting fast transient recovery (<10 µs). |
Use Scenario: Voltage sensing and regulation in 3-phase rectified 400 VAC industrial power supplies feeding PLC I/O modules. IC Role / Device Role / Timing Role: Adjustable reference for TL431QDR-based error amplifier driving PWM controller in continuous conduction mode (CCM) PFC stage. Use Value: Maintains stable 24 V output despite wide input variation (300–450 VDC) and ambient temperature swings (−25°C to +70°C). |
| Servo Drive Control Module | Notebook PC Power Adapter |
Use Scenario: Isolated feedback for 24 V auxiliary supply powering gate drivers and position encoder interfaces in CNC motion controllers. IC Role / Device Role / Timing Role: Shunt reference referenced to primary ground, interfacing with linear optocoupler for galvanic isolation. Use Value: Delivers <10 ppm/°C effective tempco via resistor network optimization, meeting servo position accuracy requirements. |
Use Scenario: Output voltage regulation in compact 65 W GaN-based USB-C PD adapters with multi-voltage negotiation (5/9/15/20 V). IC Role / Device Role / Timing Role: Programmable reference for secondary-side controller IC, enabling dynamic voltage reconfiguration via DAC-controlled divider. Use Value: Supports seamless transition between PD profiles with <0.5% voltage error and <100 µs settling time per step. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDR | Commercial-grade (0°C to 70°C), same SOT-23-3 package and 2.495 V reference, but ±2% initial tolerance (standard grade). | Limited to non-automotive, indoor-rated equipment; unsuitable for under-hood or industrial cabinet environments. | Select TL431CDR only when cost sensitivity outweighs temperature range and accuracy requirements. |
| TLVH431QDBVR | Lower 1.24 V reference voltage, 0.5% tolerance, Q-temp rated, SOT-23-3, but higher 10 µA reference current and 0.5 Ω impedance. | Better suited for low-voltage rails (≤5 V); less ideal for high-voltage feedback due to reduced headroom and higher noise. | Choose TLVH431QDBVR when designing sub-3 V output regulators or space-constrained low-power systems. |
Compared with TL431CDR and TLVH431QDBVR, TL431QDR uniquely balances automotive temperature range, ±0.5% accuracy, and ultra-low 0.2 Ω impedance-making it optimal for high-reliability isolated power supplies where regulation stability under thermal stress is critical.
Availability
TL431QDR is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC conversion, and servo drive control modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL431QDR 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 leadership in precision reference design.
The TL431 product line was engineered for high-accuracy, low-drift voltage regulation in isolated power supplies and industrial control systems-emphasizing robustness, programmability, and broad temperature performance.
FAQ
What is the reference voltage tolerance of TL431QDR at 25°C?
The TL431QDR has a ±0.5% initial reference voltage tolerance at 25°C (B grade), corresponding to a 2.483 V to 2.507 V range. This tight tolerance is specified in TI's SLVS543S datasheet Section 6.13 and enables high-accuracy output regulation without calibration. The TL431QDR maintains this specification across its full −40°C to +125°C operating range with ≤14 mV total deviation.
Can TL431QDR replace a Zener diode in feedback circuits?
Yes, TL431QDR is explicitly designed as a superior replacement for Zener diodes in voltage regulation feedback paths. Its active amplifier architecture delivers sharp turn-on, 0.2 Ω dynamic impedance, and programmable output (2.5 V to 36 V) - unlike passive Zeners, which exhibit poor regulation, high impedance, and limited voltage options. TL431QDR eliminates Zener-related drift and noise issues in switch-mode power supplies.
What is the minimum cathode current required for TL431QDR regulation?
The TL431QDR requires a minimum cathode current of 0.4 mA to maintain regulation, as confirmed in Section 6.13 of the SLVS543S datasheet. This value ensures stable operation even under light-load conditions in auxiliary power rails or low-power feedback networks. Below 0.4 mA, the device may exit regulation and exhibit increased output impedance and voltage error.
Does TL431QDR support operation above 36 V cathode-to-anode voltage?
No, TL431QDR has an absolute maximum cathode-to-anode voltage (VKA) of 37 V, with recommended operation up to 36 V per Section 6.4 of the datasheet. Exceeding 36 V risks permanent damage or parametric shift. For higher-voltage applications, external series resistors or clamping circuits must be used to limit VKA within safe limits.
How does TL431QDR differ from TL431CDR in terms of temperature performance?
TL431QDR is rated for −40°C to +125°C operation (Q grade), while TL431CDR is limited to 0°C to +70°C (C grade). Both share identical electrical specs at 25°C, but TL431QDR guarantees ≤14 mV reference voltage deviation over its full range versus ≤6 mV for TL431CDR over its narrower range. This makes TL431QDR suitable for automotive and industrial environments where thermal extremes occur.
TL431QDR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- 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:
- 8-SOIC
TL431QDR FAQ
1.How can I place an order for TL431QDR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431QDR 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 TL431QDR reliable?
The price and inventory of TL431QDR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431QDR is usually 5 days.
3.What payment methods are accepted for TL431QDR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431QDR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431QDR?
TL431QDR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431QDR 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 TL431QDR?
For technical support, including TL431QDR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431QDR requirements.
6.How does Aetrix verify that TL431QDR is sourced from the original manufacturer or authorized distributors?
All TL431QDR 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 TL431QDR meets industry standards.
7.What is the process for return or replacement of TL431QDR?
All TL431QDR units undergo pre-shipment inspection (PSI). If there is an issue with TL431QDR, 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 TL431QDR part is unused and in its original packaging.
Return procedure for TL431QDR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431QDR Tags
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TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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AN431AN-ATRG1
Diodes Incorporated
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LM4040CYM3-2.5-TR
Microchip Technology
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LM4040CYM3-4.1-TR
Microchip Technology
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LM4040EIM3-2.5/NOPB
Texas Instruments
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AZ431LBNTR-G1
Diodes Incorporated
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LM4040D20IDBZR
Texas Instruments
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LM4041DIM3-ADJ/NOPB
Texas Instruments
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LM4040DIM3X-2.5/NOPB
Texas Instruments
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LM4040DIM3-2.5/NOPB
Texas Instruments
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AZ431LANTR-G1
Diodes Incorporated
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