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Texas Instruments TL431QDBZT
- Part No.:
- TL431QDBZT
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431QDBZT.pdf
- Description:
- IC VREF SHUNT ADJ 2.2% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:1,392
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Product details
Overview
TL431QDBZT 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 TL431QDBZT datasheet, TL431QDBZT pinout, TL431QDBZT application, or TL431QDBZT equivalent, key selection criteria include automotive-grade temperature range (−40°C to 125°C), low-output-impedance regulation stability, sink-current capability up to 100 mA, and compatibility with standard resistor-divider feedback networks.
Technical Context
The TL431QDBZT implements a bandgap-referenced error amplifier driving an NPN output transistor in a three-terminal shunt topology. Its internal architecture enables precise voltage regulation by comparing the REF pin voltage against the 2.495 V reference and adjusting cathode current to maintain setpoint.
It supports adjustable output voltages from 2.5 V to 36 V using two external resistors, features sharp turn-on characteristics for Zener diode replacement, and maintains stable operation under varying load and line conditions across its full Q-temp range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V nominal (min 2.483 V, max 2.507 V at 25°C); enables accurate feedback setpoints in power supply loops. |
| Initial Tolerance | ±0.5% at 25°C (B grade); reduces calibration overhead in high-accuracy AC/DC and servo drive designs. |
| 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 (≤0.5 Ω max); ensures minimal output voltage deviation during fast load transients. |
| Sink Current | 1 mA to 100 mA; supports direct interface with optocoupler LEDs and gate drivers without external buffering. |
| Ref Input Current | 2–4 µA typical; allows use of high-value feedback resistors (>1 MΩ) to minimize power loss in battery-powered systems. |
| Temp Drift (VI(dev)) | 14–34 mV over full range; verified stability for closed-loop regulation in wide-temperature industrial inverters. |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm body size), surface-mount, lead-free, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (REF) | Reference input | High-impedance threshold node; connected to resistor divider midpoint to sense regulated output voltage. |
| Pin 2 (CATHODE) | Shunt current output | Sinks current to adjust feedback loop; directly drives optocoupler anode or error amplifier input in isolated topologies. |
| Pin 3 (ANODE) | Common return | Typically tied to system ground or power supply return; establishes reference potential for internal bandgap circuitry. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output range | 2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-voltage references in multi-rail systems. |
| Low output noise | Sub-20 µVPP (0.1–10 Hz); preserves signal integrity in precision analog feedback paths and sensor excitation circuits. |
| Sharp turn-on characteristic | Fast response to reference threshold crossing - enables clean regulation without oscillation in switching power supplies. |
| Automotive qualification | AEC-Q100 Grade 1 compliant (−40°C to +125°C); suitable for safety-critical vehicle subsystems including ADAS power rails. |
| ESD robustness | ±2000 V HBM - withstands handling and board-level ESD events in automated manufacturing and field service. |
Applications
| Rack Server Power | Industrial AC/DC Converter |
|---|---|
|
Use Scenario: Secondary-side voltage regulation in 48 V telecom rectifiers with optocoupler-based isolation. IC Role / Device Role / Timing Role: Shunt reference providing feedback to isolated error amplifier; sets precise 12 V or 5 V output rails. Use Value: ±0.5% initial accuracy and 14 mV temp drift ensure output stays within ±1% over full operating temperature, meeting IEC 62368-1 compliance. |
Use Scenario: Output voltage sensing in 3 kW industrial SMPS for CNC machine tool power modules. IC Role / Device Role / Timing Role: Adjustable shunt regulator in primary-side feedback network; interfaces with PWM controller via TL431-compatible optocoupler. Use Value: 0.2 Ω dynamic impedance minimizes load-regulation error (<0.2%) across 10–100% load steps, improving process repeatability. |
| AC Inverter Drive | Servo Drive Control Module |
|
Use Scenario: DC bus voltage monitoring and overvoltage protection threshold in 3-phase VFDs. IC Role / Device Role / Timing Role: Precision voltage comparator reference; triggers shutdown when bus exceeds 800 V via resistor scaling. Use Value: −40°C to +125°C operation ensures reliable trip point accuracy inside enclosed motor cabinets exposed to ambient heat and vibration. |
Use Scenario: Feedback stabilization in dual-loop (current + velocity) servo amplifiers for robotic joint actuators. IC Role / Device Role / Timing Role: Low-noise reference source for DAC output buffering and current-sense amplifier offset trimming. Use Value: Sub-20 µVPP low-frequency noise prevents torque ripple induced by reference instability at <10 Hz servo bandwidths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBZT | Same SOT-23-3 package but rated for 0°C to 70°C only; ±0.5% tolerance retained. | Limited to commercial-temperature environments (e.g., office equipment, non-enclosed adapters). | Select when cost sensitivity outweighs extended temperature requirement and ambient stays below 70°C. |
| TLVH431QDBZR | Lower 1.24 V reference voltage; same Q-temp rating; 0.3 Ω dynamic impedance; SOT-23-3. | Enables lower-voltage feedback (e.g., 3.3 V, 2.5 V rails); higher ref current (100 nA typ) limits high-resistor use. | Choose when designing sub-2.5 V regulated outputs or needing tighter low-voltage tolerance (±0.5% at 1.24 V). |
Compared with TL431CDBZT and TLVH431QDBZR, TL431QDBZT uniquely combines automotive-grade temperature range, 2.495 V reference, and 0.2 Ω impedance-making it optimal for high-stability, isolated power regulation where both accuracy and thermal resilience are mandatory.
Availability
TL431QDBZT 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 TL431QDBZT 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 and embedded processing technologies, with decades of expertise in precision reference design and power management ICs.
The TL431 product line was engineered for high-accuracy, low-drift voltage regulation in isolated switching power supplies, industrial controls, and automotive systems-emphasizing stability, noise performance, and broad temperature operation.
FAQ
What is the reference voltage tolerance of TL431QDBZT at 25°C?
The TL431QDBZT has a ±0.5% initial reference voltage tolerance at 25°C (B grade), corresponding to a 2.483 V to 2.507 V range around the nominal 2.495 V. This tight tolerance is specified per TI's SLVS543S datasheet Section 6.13 and enables reduced calibration effort in high-accuracy power supplies. The TL431QDBZT maintains this grade across its full −40°C to +125°C operating range.
Can TL431QDBZT replace a Zener diode in feedback circuits?
Yes, TL431QDBZT is explicitly designed as a superior Zener diode replacement in feedback networks. Its active error amplifier delivers sharp turn-on, low dynamic impedance (0.2 Ω), and stable 2.495 V reference-unlike passive Zeners that suffer from poor tempco and impedance variation. The TL431QDBZT achieves this while using only three pins and standard resistor dividers, as confirmed in the TI datasheet Section 3 and Figure 9-1.
What is the maximum cathode current supported by TL431QDBZT?
The TL431QDBZT supports continuous cathode current from 1 mA to 100 mA, as defined in Section 6.4 (Recommended Operating Conditions) and validated in electrical characteristics tables (Sections 6.7, 6.13). Operation beyond 100 mA risks exceeding thermal limits-especially in SOT-23-3 packaging-so derating is advised above 70 mA at elevated ambient temperatures.
Does TL431QDBZT require external compensation for stability?
TL431QDBZT does not require external compensation in most configurations, but stability depends on load capacitance and cathode current. Per Figures 6-18 and 6-19 in the datasheet, oscillation risk increases with >100 nF capacitive loads at low cathode currents (<10 mA). For robust operation, keep CL ≤ 10 nF or add a series resistor (e.g., 100 Ω) between cathode and capacitor when CL > 100 nF. The TL431QDBZT's inherent phase margin avoids compensation in standard optocoupler feedback designs.
How does TL431QDBZT differ from TL431CDBZT?
TL431QDBZT and TL431CDBZT share identical SOT-23-3 packaging and ±0.5% reference tolerance, but differ in temperature rating: TL431QDBZT is qualified for −40°C to +125°C (Q grade), while TL431CDBZT is limited to 0°C to +70°C (C grade). Electrical parameters like dynamic impedance and temp drift are otherwise matched per TI's device comparison table (Section 4), making TL431QDBZT the only choice for automotive or high-ambient industrial use.
TL431QDBZT 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
TL431QDBZT FAQ
1.How can I place an order for TL431QDBZT through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431QDBZT 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 TL431QDBZT reliable?
The price and inventory of TL431QDBZT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431QDBZT is usually 5 days.
3.What payment methods are accepted for TL431QDBZT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431QDBZT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431QDBZT?
TL431QDBZT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431QDBZT 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 TL431QDBZT?
For technical support, including TL431QDBZT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431QDBZT requirements.
6.How does Aetrix verify that TL431QDBZT is sourced from the original manufacturer or authorized distributors?
All TL431QDBZT 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 TL431QDBZT meets industry standards.
7.What is the process for return or replacement of TL431QDBZT?
All TL431QDBZT units undergo pre-shipment inspection (PSI). If there is an issue with TL431QDBZT, 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 TL431QDBZT part is unused and in its original packaging.
Return procedure for TL431QDBZT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431QDBZT Tags
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TL431AIDBZR
Texas Instruments
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TL431BQDBZR
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AN431AN-ATRG1
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LM4040CYM3-2.5-TR
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LM4040EIM3-2.5/NOPB
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AZ431LBNTR-G1
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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
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AZ431LANTR-G1
Diodes Incorporated
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