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Texas Instruments TL431CDBZR
- Part No.:
- TL431CDBZR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431CDBZR.pdf
- Description:
- IC VREF SHUNT ADJ 2.2% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:15,280
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Product details
Overview
TL431CDBZR 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, 0.2 Ω typical dynamic impedance, and operation from 0°C to 70°C. It replaces Zener diodes in adjustable power supplies, isolated feedback loops, and voltage monitoring circuits requiring stable 2.5 V reference.
For engineers reviewing the TL431CDBZR datasheet, TL431CDBZR pinout, TL431CDBZR application, or TL431CDBZR equivalent, key selection criteria include its 2.495 V reference accuracy, 1 mA–100 mA sink-current capability, low 6 mV temperature drift (C-grade), and SOT-23-3 footprint compatibility with space-constrained DC/DC and AC/DC designs.
Technical Context
The TL431CDBZR implements a three-terminal adjustable shunt regulator architecture with an internal error amplifier, reference, and output transistor. Its REF pin senses voltage relative to ANODE, enabling precise external resistor-based output setting from 2.495 V to 36 V. The device operates as a high-gain transconductance amplifier with sharp turn-on characteristics.
It features active output circuitry that delivers low 0.2 Ω dynamic impedance and maintains regulation down to 0.4 mA minimum cathode current. Temperature stability is ensured by low 6 mV total deviation over 0°C–70°C and minimal ΔVref/ΔVKA sensitivity (−1.4 to −2.7 mV/V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V (nominal); enables accurate 2.5 V system-level voltage sensing and feedback setpoint |
| Initial Tolerance | ±0.5% at 25°C (B-grade); ensures tight output regulation without trimming in production |
| Temp Range | 0°C to 70°C (C-grade); suitable for commercial ambient environments like notebook adapters and rack servers |
| Dynamic Impedance | 0.2 Ω typical; provides stiff reference under load transients and suppresses ripple in feedback paths |
| Sink Current Range | 1 mA to 100 mA; supports direct drive of optocoupler LEDs or small-signal loads without buffering |
| Temp Drift (VI(dev)) | 6 mV max over full range; guarantees ≤0.024% /°C average coefficient for stable long-term performance |
| Ref Input Current | 2–4 µA typical; minimizes resistor-divider loading error and enables high-impedance feedback networks |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm), surface-mount, lead-free, RoHS-compliant. Pin 1 = REF, Pin 2 = CATHODE, Pin 3 = ANODE.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REF (Pin 1) | Reference input | Senses voltage divider output; sets regulation point when referenced to ANODE |
| CATHODE (Pin 2) | Shunt current output | Carries regulated sink current; connects to primary-side controller feedback node in isolated SMPS |
| ANODE (Pin 3) | Common return | Typically tied to ground or negative rail; serves as voltage reference point for REF and cathode current path |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output range | 2.495 V to 36 V via two external resistors - eliminates need for multiple fixed references |
| Low output noise | Sub-20 µVRMS (0.1–10 Hz); preserves signal integrity in precision analog feedback loops |
| Sharp turn-on characteristic | Fast response to reference threshold crossing - enables clean switching in overvoltage protection circuits |
| High gain transconductance stage | ~1 A/V typical transconductance - ensures stable closed-loop behavior with minimal phase margin loss |
| ESD robustness | ±2000 V HBM - withstands handling and board assembly without special precautions |
Applications
| Rack Server Power | Industrial AC/DC Converter |
|---|---|
Use Scenario: Primary-side feedback in isolated 48 V–12 V DC/DC modules for telecom and data center PSUs. IC Role / Device Role / Timing Role: Shunt reference providing precise 2.5 V setpoint to optocoupler LED, enabling secondary-side voltage regulation across isolation barrier. Use Value: ±0.5% reference accuracy ensures <±1% output voltage tolerance across line/load/temperature, meeting ATX and OCP specifications. |
Use Scenario: Output voltage sensing and regulation in 300 W industrial AC/DC front-end supplies. IC Role / Device Role / Timing Role: Adjustable shunt regulator in feedback network of PWM controller, setting 24 V output with external R1/R2 divider. Use Value: 0.2 Ω dynamic impedance maintains loop stability under fast load steps, reducing output overshoot below 50 mV. |
| Notebook PC Adapter | Servo Drive Control Module |
Use Scenario: Secondary-side voltage monitor in compact 65 W laptop adapter with synchronous rectification. IC Role / Device Role / Timing Role: Precision reference for error amplifier in flyback controller IC, comparing sensed output against 2.495 V threshold. Use Value: 6 mV max temp drift over 0°C–70°C prevents thermal-induced output drift beyond ±0.2%, critical for USB-C PD compliance. |
Use Scenario: Overvoltage protection trigger in 3-phase servo motor driver power stage. IC Role / Device Role / Timing Role: Threshold detector comparing bus voltage against 30 V setpoint (via R1/R2), sinking current to disable gate driver on fault. Use Value: 100 mA sink capability allows direct drive of logic-level shutdown input without buffer transistor, reducing BOM count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDBZR | ±1% initial tolerance (A-grade) vs. ±0.5% (B-grade); otherwise identical electrical specs and SOT-23-3 package | Acceptable where tighter than 1% output regulation is not required; lower cost for non-critical rails | Select TL431ACDBZR only if system-level voltage tolerance budget permits ±1% reference contribution. |
| TLVH431IDBZR | Lower 1.24 V reference voltage; wider 1.24 V–18 V output range; higher 10 µA max IREF; same SOT-23-3 package | Better suited for low-voltage systems (<3.3 V) or battery-powered applications needing sub-2.5 V thresholds | Choose TLVH431IDBZR when designing 1.8 V or 3.3 V LDO feedback or low-VOUT SMPS; not drop-in for 2.5 V setpoints. |
Compared with TL431ACDBZR, TL431CDBZR offers tighter initial accuracy for demanding regulation, while TLVH431IDBZR trades reference voltage and current specs for low-voltage flexibility-neither is pin-compatible for direct 2.5 V replacement without circuit revalidation.
Availability
TL431CDBZR is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and notebook PC adapter designs requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.
Supply support for TL431CDBZR 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 expertise in precision reference design and high-volume manufacturing.
The TL431 product line was engineered for high-accuracy, low-drift voltage regulation in power supply feedback, battery management, and industrial control systems-delivering Zener-replacement performance with superior thermal stability and sink-current capability.
FAQ
What is the reference voltage tolerance of TL431CDBZR at 25°C?
The TL431CDBZR has a ±0.5% initial reference voltage tolerance at 25°C, corresponding to a 2.495 V nominal value with a 2.483–2.507 V range. This B-grade accuracy is confirmed in Section 6.11 of the TI datasheet SLVS543S and enables high-precision feedback without external calibration. TL431CDBZR maintains this specification across its SOT-23-3 package variant and is validated for use in commercial-temperature applications.
Can TL431CDBZR replace a Zener diode in a power supply feedback loop?
Yes, TL431CDBZR is explicitly designed as a superior Zener diode replacement in power supply feedback loops. Its active error amplifier architecture delivers sharper turn-on, lower dynamic impedance (0.2 Ω vs. typical Zener's >10 Ω), and tighter voltage tolerance (±0.5% vs. ±5% for standard Zeners). TL431CDBZR also supports adjustable outputs from 2.495 V to 36 V using two resistors-unlike fixed-voltage Zeners-and is qualified for use in isolated flyback and forward converter topologies per TI's application notes.
What is the operating temperature range of TL431CDBZR?
TL431CDBZR is rated for operation from 0°C to 70°C (C-grade), as defined in Section 4 of the TI datasheet SLVS543S. This commercial temperature range aligns with applications such as notebook PC adapters, consumer power bricks, and non-automotive industrial equipment. The device exhibits ≤6 mV total reference voltage deviation across this range, ensuring stable regulation without derating. TL431CDBZR is not rated for extended industrial (−40°C to 85°C) or automotive (−40°C to 125°C) temperatures.
How does TL431CDBZR achieve low output impedance?
TL431CDBZR achieves 0.2 Ω typical dynamic impedance through its integrated high-gain transconductance amplifier and active output stage, which continuously adjusts cathode current to maintain constant reference voltage. Unlike passive Zeners, this closed-loop regulation rejects load and line variations effectively. Measured per Figure 6-12 in the datasheet, |ZKA| remains ≤0.5 Ω up to 100 kHz, making TL431CDBZR effective in suppressing ripple and noise in feedback paths of switching regulators.
What are the absolute maximum ratings for TL431CDBZR cathode voltage and current?
The absolute maximum cathode voltage (VKA) for TL431CDBZR is 37 V, and the continuous cathode current (IKA) ranges from −100 mA to +150 mA, per Section 6.1 of the TI datasheet SLVS543S. These ratings define safe operating limits-not recommended conditions. For reliable operation, TI specifies 1–100 mA sink current and VKA between Vref and 36 V. Exceeding 37 V or 150 mA risks permanent damage, even briefly.
TL431CDBZR 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
TL431CDBZR FAQ
1.How can I place an order for TL431CDBZR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431CDBZR 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 TL431CDBZR reliable?
The price and inventory of TL431CDBZR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431CDBZR is usually 5 days.
3.What payment methods are accepted for TL431CDBZR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431CDBZR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431CDBZR?
TL431CDBZR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431CDBZR 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 TL431CDBZR?
For technical support, including TL431CDBZR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431CDBZR requirements.
6.How does Aetrix verify that TL431CDBZR is sourced from the original manufacturer or authorized distributors?
All TL431CDBZR 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 TL431CDBZR meets industry standards.
7.What is the process for return or replacement of TL431CDBZR?
All TL431CDBZR units undergo pre-shipment inspection (PSI). If there is an issue with TL431CDBZR, 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 TL431CDBZR part is unused and in its original packaging.
Return procedure for TL431CDBZR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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