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Texas Instruments TL431ACDBZT
- Part No.:
- TL431ACDBZT
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431ACDBZT.pdf
- Description:
- IC VREF SHUNT ADJ 1% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,896
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Product details
Overview
TL431ACDBZT 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 at 25°C, 1 mA–100 mA sink-current capability, and operation across –40°C to 125°C. It replaces Zener diodes in feedback loops of isolated DC/DC converters, AC/DC adapters, and industrial power supplies.
For engineers reviewing the TL431ACDBZT datasheet, TL431ACDBZT pinout, TL431ACDBZT application, or TL431ACDBZT equivalent, key selection criteria include its A-grade accuracy, Q-temp automotive qualification, low 0.2 Ω dynamic impedance, and stable performance under varying cathode voltage (VKA) and load conditions.
Technical Context
The TL431ACDBZT implements an internal error amplifier with high-gain transconductance stage driving a NPN output transistor, enabling sharp turn-on and precise regulation via external resistor divider between cathode and reference pins. Its three-terminal shunt architecture requires no external biasing beyond the resistive network setting VOUT = VREF(1 + R1/R2).
Designed for closed-loop feedback in switching regulators, it maintains regulation with cathode voltage ranging from VREF (~2.5 V) to 36 V and exhibits minimal drift-14 mV max deviation over –40°C to 125°C-due to matched on-die bipolar transistor pairs and curvature-compensated bandgap core.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V nominal (A-grade), ±0.5% tolerance at 25°C - ensures tight output setpoint in power supply feedback paths |
| Operating Temperature | –40°C to +125°C - qualified for automotive and industrial environments without derating |
| Sink Current Range | 1 mA to 100 mA - supports direct drive of optocoupler LEDs or error amplifier inputs without buffering |
| Dynamic Impedance | 0.2 Ω typical - minimizes output voltage perturbation during transient load steps in regulated supplies |
| Reference Input Current | 2–4 µA - enables high-impedance voltage divider design (e.g., 10 kΩ/10 kΩ) with negligible current error |
| Temp Drift (VI(dev)) | 14 mV max over full range - translates to <0.012%/°C average TC, critical for long-term output stability |
| Off-State Cathode Current | ≤0.5 µA at VKA = 36 V - ensures minimal standby power loss in always-on auxiliary rails |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm), surface-mount, tape-and-reel compatible. Pin 1 = Cathode, Pin 2 = Reference, Pin 3 = Anode.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 1) | Shunt current input / output node | Connects to switched node or feedback point; sinks current to regulate voltage at REF pin |
| Reference (Pin 2) | High-impedance threshold input | Compares divided output voltage against internal 2.495 V reference; sets regulation point |
| Anode (Pin 3) | Common return path | Typically tied to system ground or power rail common; defines voltage reference for REF and CATHODE |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output Range | 2.5 V to 36 V via two-resistor divider - eliminates need for multiple fixed references in multi-rail systems |
| Low Output Noise | ~200 nV/√Hz at 1 kHz - preserves signal integrity in precision analog feedback loops |
| Sharp Turn-On Characteristic | Sub-100 ns response to REF threshold crossing - enables fast loop correction in high-frequency SMPS |
| Thermal Stability | 14 mV max VREF deviation over –40°C to +125°C - meets AEC-Q100 Grade 1 requirements |
| ESD Robustness | ±2000 V HBM - withstands handling and board assembly without protection circuitry |
Applications
| Rack Server Power | Industrial AC/DC Converters |
|---|---|
Use Scenario: Secondary-side voltage regulation 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 control optocoupler LED current and thus primary-side PWM duty cycle. Use Value: Enables ±1% output voltage accuracy across line/load/temperature while reducing component count vs. discrete Zener+transistor solutions. |
Use Scenario: Feedback reference in 3 kW industrial rectifier with active PFC and LLC resonant output stage. IC Role / Device Role / Timing Role: Precision shunt regulator setting 12 V output via resistor divider, interfacing with isolated error amplifier. Use Value: Maintains regulation stability under wide input voltage swings (85–265 VAC) and high ambient temperatures (up to 70°C chassis). |
| AC Inverter Drives | Notebook PC Power Adapters |
Use Scenario: Voltage sensing and protection reference in 3-phase motor drive DC bus monitoring circuit. IC Role / Device Role / Timing Role: High-accuracy shunt reference feeding comparator inputs for overvoltage lockout and soft-start sequencing. Use Value: Delivers 14 mV max drift over –40°C to +125°C, ensuring reliable trip thresholds across motor thermal cycles. |
Use Scenario: Output voltage regulation in compact 65 W GaN-based USB-C PD adapter with synchronous rectification. IC Role / Device Role / Timing Role: Adjustable shunt reference setting 20 V output via 1% metal-film resistors, directly driving optocoupler LED. Use Value: Achieves <0.5% load regulation and <1% line regulation while fitting within 30 mm × 30 mm PCB area constraint. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBZT | 0°C–70°C temp range; 2% initial tolerance (standard grade) | Limited to commercial-temperature consumer power supplies | Select when cost sensitivity outweighs automotive/industrial temperature or accuracy requirements |
| TL431BQDBZR | SOT-23-5 package; 0.5% tolerance; same Q-temp rating but different pinout (REF/ANODE/CATHODE order differs) | Requires PCB layout revision due to non-pin-compatible pin assignment | Choose only if higher ESD immunity (±2.5 kV) or alternate thermal profile (RθJA = 206°C/W vs. 206°C/W) is prioritized |
Compared with TL431CDBZT, TL431ACDBZT provides tighter accuracy and extended temperature range at modest cost premium; versus TL431BQDBZR, it offers identical electrical specs in the industry-standard SOT-23-3 footprint, avoiding redesign risk.
Availability
TL431ACDBZT is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and AC inverter drives requiring stable component supply with guaranteed long-term manufacturability.
Supply support for TL431ACDBZT 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 leadership in precision analog ICs and power management solutions.
The TL431 product line was engineered for high-accuracy, low-drift voltage regulation in safety-critical power conversion systems-particularly where Zener diodes lack stability, noise performance, or temperature behavior.
FAQ
What is the reference voltage tolerance of TL431ACDBZT at 25°C?
The TL431ACDBZT has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a nominal 2.495 V output with minimum 2.470 V and maximum 2.520 V. This A-grade accuracy is specified in Section 6.8 of the TI SLVS543S datasheet and applies exclusively to the TL431ACDBZT variant with SOT-23-3 packaging and Q-temp qualification.
Can TL431ACDBZT replace a standard Zener diode in feedback circuits?
Yes, TL431ACDBZT 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 14 mV max temperature drift over –40°C to +125°C provide significantly better stability and accuracy than typical 5% tolerance Zeners, especially in switching power supplies where loop dynamics matter.
What is the maximum cathode voltage rating for TL431ACDBZT?
The absolute maximum cathode voltage (VKA) for TL431ACDBZT is 37 V, with recommended operating range from VREF (~2.5 V) up to 36 V. Exceeding 37 V risks permanent damage per Section 6.1 of the datasheet; operation above 36 V is not supported for regulation functionality.
Does TL431ACDBZT require external capacitors for stability?
TL431ACDBZT can oscillate with certain load capacitances and cathode voltages-stability boundaries are defined in Figures 6-18 and 6-19 of the datasheet. A 1 nF ceramic capacitor from cathode to anode is commonly used to ensure stability across all operating conditions, particularly when driving optocouplers with long traces.
Is TL431ACDBZT pin-compatible with other TL431 variants in SOT-23-3?
Yes, TL431ACDBZT shares identical SOT-23-3 pinout (Cathode–Reference–Anode) with all TL431x DBZ variants-including TL431CDBZT and TL431BDBZT-making it a drop-in upgrade for improved accuracy and temperature range without PCB changes.
TL431ACDBZT 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:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 600 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
TL431ACDBZT FAQ
1.How can I place an order for TL431ACDBZT through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431ACDBZT 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 TL431ACDBZT reliable?
The price and inventory of TL431ACDBZT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431ACDBZT is usually 5 days.
3.What payment methods are accepted for TL431ACDBZT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431ACDBZT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431ACDBZT?
TL431ACDBZT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431ACDBZT 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 TL431ACDBZT?
For technical support, including TL431ACDBZT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431ACDBZT requirements.
6.How does Aetrix verify that TL431ACDBZT is sourced from the original manufacturer or authorized distributors?
All TL431ACDBZT 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 TL431ACDBZT meets industry standards.
7.What is the process for return or replacement of TL431ACDBZT?
All TL431ACDBZT units undergo pre-shipment inspection (PSI). If there is an issue with TL431ACDBZT, 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 TL431ACDBZT part is unused and in its original packaging.
Return procedure for TL431ACDBZT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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