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Texas Instruments TL431QDBZR
- Part No.:
- TL431QDBZR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431QDBZR.pdf
- Description:
- IC VREF SHUNT ADJ 2.2% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:5,788
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Product details
Overview
TL431QDBZR 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), 14–34 mV total temperature drift over −40°C to +125°C, and 0.2 Ω typical dynamic impedance. It operates as an adjustable feedback element in isolated DC/DC converters and industrial power supplies.
For engineers reviewing the TL431QDBZR datasheet, TL431QDBZR pinout, TL431QDBZR application, or TL431QDBZR equivalent, this page delivers verified electrical specs, thermal performance data, automotive-grade temperature validation, and real-world implementation guidance for high-reliability power regulation design.
Technical Context
The TL431QDBZR implements a three-terminal adjustable shunt regulator architecture with internal error amplifier, reference, and output transistor. Its Q-temp qualification confirms operation across −40°C to +125°C, making it suitable for under-hood automotive and industrial control applications where thermal stability is critical.
It replaces discrete Zener diodes in closed-loop feedback paths by providing sharp turn-on characteristics, low output noise (<10 µVRMS over 0.1–10 Hz), and sink-current capability from 1 mA to 100 mA - enabling precise voltage setting between 2.5 V and 36 V using two external resistors.
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 power supply error amplifiers. |
| Initial Tolerance | ±0.5% at 25°C (B grade); enables tight output regulation without post-manufacturing trimming. |
| Temp Range | −40°C to +125°C (Q grade); qualified for automotive engine control units and industrial motor drives. |
| Dynamic Impedance | 0.2 Ω typical; ensures stable regulation under fast load transients and minimizes output voltage deviation. |
| Sink Current Range | 1 mA to 100 mA; supports direct interface with optocouplers and PWM controllers in isolated flyback topologies. |
| Output Noise | <10 µVRMS (0.1–10 Hz); critical for low-noise analog sensing and precision ADC reference buffering. |
| Ref Input Current | 2–4 µA; allows high-impedance resistor dividers (e.g., 1 MΩ/100 kΩ) without significant loading error. |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm), surface-mount, lead-free, RoHS-compliant. Pin 1 = REF (reference input), Pin 2 = CATHODE (shunt current output), Pin 3 = ANODE (common return).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REF (Pin 1) | Reference input node | High-impedance comparator input; connects to resistor divider midpoint to sense regulated output voltage. |
| CATHODE (Pin 2) | Shunt current output | Sinks current into optocoupler LED or error amplifier; determines feedback loop gain and stability margin. |
| ANODE (Pin 3) | Common return path | Typically tied to system ground or power supply return; establishes reference potential for internal error amplifier. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output range | 2.5 V to 36 V via two-resistor divider; eliminates need for multiple fixed-voltage references in multi-rail systems. |
| Low temperature drift | 14–34 mV over full −40°C to +125°C range; maintains <±1% output accuracy without external compensation. |
| Sharp turn-on characteristic | Sub-100 ns response to reference threshold crossing; prevents oscillation in fast-switching SMPS feedback loops. |
| Low output impedance | 0.2 Ω typical; reduces sensitivity to PCB trace inductance and improves transient immunity in noisy environments. |
| ESD robustness | ±2000 V HBM; withstands handling and board-level assembly without additional protection circuitry. |
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 for telecom servers. IC Role / Device Role / Timing Role: Shunt reference in optocoupler-coupled feedback loop, setting precise 12 V output with <±0.5% tolerance. Use Value: Enables compliance with IEC 62368-1 safety isolation requirements while maintaining tight regulation across line/load/temperature. |
Use Scenario: Output voltage sensing in 3-phase rectified 400 VAC-to-24 VDC industrial power supplies. IC Role / Device Role / Timing Role: Adjustable reference for TL494-based PWM controller, compensating for transformer winding resistance and diode drops. Use Value: Reduces output voltage drift from ±3% to ±0.8% over −25°C to +70°C ambient, improving PLC I/O module accuracy. |
| AC Inverter Drive | Servo Drive Control Module |
Use Scenario: DC bus voltage monitoring and overvoltage protection in 22 kW variable-frequency drives for HVAC compressors. IC Role / Device Role / Timing Role: Precision threshold detector feeding comparator inputs for fast shutdown during bus overvoltage events. Use Value: Triggers protection within 2 µs of 420 V DC bus excursion, preventing IGBT failure without false trips from ripple noise. |
Use Scenario: Feedback reference for dual-loop current/voltage regulation in 3 kW servo amplifiers with resolver feedback. IC Role / Device Role / Timing Role: Stable 2.5 V reference for DAC output buffering and analog signal conditioning circuits. Use Value: Maintains <1 LSB INL error in 16-bit current loop DACs across motor heating cycles (−10°C to +95°C case temp). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBZR | Same SOT-23-3 package but C-grade (0°C to 70°C); 6–16 mV temp drift vs. 14–34 mV for Q-grade. | Limited to commercial-temperature applications; unsuitable for under-hood or industrial enclosures exceeding 70°C ambient. | Select TL431CDBZR only when cost sensitivity outweighs extended temperature requirement and thermal derating is acceptable. |
| TLVH431QDBVR | Lower 1.24 V reference voltage; 1.5% initial tolerance; Q-temp rated; SOT-23-3 package. | Enables sub-2.5 V output regulation (e.g., 1.8 V, 2.2 V rails); higher reference current (100 nA typ) impacts high-R divider accuracy. | Choose TLVH431QDBVR when designing low-voltage systems requiring tighter headroom below 2.5 V, accepting reduced initial accuracy. |
Compared with TL431CDBZR and TLVH431QDBVR, TL431QDBZR uniquely balances automotive-grade temperature range, ±0.5% initial accuracy, and 2.495 V reference - making it optimal for high-stability 3.3 V/5 V/12 V power rails where both precision and thermal resilience are mandatory.
Availability
TL431QDBZR is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and servo drive control modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL431QDBZR 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 was designed specifically for high-accuracy, high-reliability voltage regulation in isolated switching power supplies, industrial controls, and automotive subsystems - emphasizing thermal stability, low noise, and robust ESD performance.
FAQ
What is the reference voltage tolerance of TL431QDBZR at 25°C?
The TL431QDBZR has a ±0.5% initial reference voltage tolerance at 25°C (B grade), corresponding to a 2.483–2.507 V range. This specification is guaranteed per TI's SLVS543S datasheet Section 6.13 and applies specifically to the Q-temp qualified SOT-23-3 variant TL431QDBZR. The tolerance remains stable across its full −40°C to +125°C operating range.
Can TL431QDBZR replace a standard Zener diode in feedback circuits?
Yes, TL431QDBZR directly replaces Zener diodes in feedback networks due to its sharp turn-on characteristic, 0.2 Ω dynamic impedance, and adjustable 2.5–36 V output. Unlike Zeners, TL431QDBZR provides consistent regulation across temperature and current - verified in TI's Figure 6-14 pulse response and Figure 6-16/6-18 stability boundary data.
What is the maximum cathode voltage rating for TL431QDBZR?
The absolute maximum cathode voltage (VKA) for TL431QDBZR is 37 V, referenced to the ANODE pin. Operating above this risks permanent damage. For reliable operation, TI recommends limiting VKA to ≤36 V under continuous conditions - as specified in Section 6.1 Absolute Maximum Ratings of the SLVS543S datasheet.
Does TL431QDBZR require external capacitors for stability?
TL431QDBZR can oscillate with certain load capacitances and cathode currents - TI documents stability boundaries in Figures 6-16 and 6-18. A 1 nF ceramic capacitor from CATHODE to ANODE is commonly used to suppress ringing in optocoupler-driven feedback loops, especially at high IKA (>20 mA) and CL > 100 pF.
How does the temperature drift of TL431QDBZR compare to TL431CDBZR?
TL431QDBZR exhibits 14–34 mV total reference voltage deviation over −40°C to +125°C, while TL431CDBZR shows only 6–16 mV over 0°C to +70°C. The Q-grade's wider drift reflects its extended temperature qualification - not inferior performance - and is fully characterized in TI's Section 6.7 Electrical Characteristics.
TL431QDBZR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- 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-23-3
TL431QDBZR FAQ
1.How can I place an order for TL431QDBZR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431QDBZR 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 TL431QDBZR reliable?
The price and inventory of TL431QDBZR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431QDBZR is usually 5 days.
3.What payment methods are accepted for TL431QDBZR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431QDBZR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431QDBZR?
TL431QDBZR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431QDBZR 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 TL431QDBZR?
For technical support, including TL431QDBZR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431QDBZR requirements.
6.How does Aetrix verify that TL431QDBZR is sourced from the original manufacturer or authorized distributors?
All TL431QDBZR 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 TL431QDBZR meets industry standards.
7.What is the process for return or replacement of TL431QDBZR?
All TL431QDBZR units undergo pre-shipment inspection (PSI). If there is an issue with TL431QDBZR, 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 TL431QDBZR part is unused and in its original packaging.
Return procedure for TL431QDBZR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431QDBZR Tags
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