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Texas Instruments TL431BCDBZR
- Part No.:
- TL431BCDBZR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431BCDBZR.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:10,745
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Product details
Overview
TL431BCDBZR from Texas Instruments is a precision programmable shunt voltage reference in SOT-23-3 package, featuring 0.5% initial reference voltage tolerance at 25°C, 2.483–2.507 V nominal Vref, and operation across −40°C to 125°C (Q-grade). It delivers 0.2 Ω typical dynamic impedance, 1–100 mA sink-current capability, and supports adjustable output from Vref to 36 V-used in feedback loops of isolated DC/DC converters and notebook power adapters.
For engineers reviewing the TL431BCDBZR datasheet, TL431BCDBZR pinout, TL431BCDBZR application, or TL431BCDBZR equivalent, key selection criteria include its Q-grade temperature range, B-grade accuracy, SOT-23-3 footprint compatibility, and shunt regulator behavior requiring external resistor network for voltage setting.
Technical Context
The TL431BCDBZR implements a three-terminal adjustable shunt regulator architecture with an internal 2.5 V reference, error amplifier, and NPN output stage. Its sharp turn-on characteristic and low 0.2 Ω dynamic impedance enable stable regulation in switching power supply feedback paths without external compensation in many cases.
As a Q-grade device, TL431BCDBZR is characterized for −40°C to 125°C operation and exhibits ≤34 mV total reference voltage deviation over that range. Its SOT-23-3 pinout (REF–CATHODE–ANODE) differs from TL432 variants and requires correct PCB layout to avoid instability-especially with capacitive loads exceeding stability boundaries defined in Figure 6-18.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (Vref) | 2.483–2.507 V at 25°C - enables precise 2.5 V threshold or adjustable output via two-resistor divider. |
| Initial Tolerance | ±0.5% (B grade) - reduces calibration overhead in production power supplies. |
| Operating Temperature | −40°C to +125°C (Q grade) - qualified for automotive under-hood and industrial servo drive environments. |
| Dynamic Impedance | 0.2 Ω typical - maintains tight output regulation under fast load transients in SMPS feedback loops. |
| Sink Current Range | 1–100 mA - supports direct interface with optocoupler LEDs in isolated flyback controllers. |
| Reference Input Current | 2–4 µA - minimizes resistor-divider power loss and improves efficiency in battery-sensitive designs. |
| Output Noise | Low broadband noise - verified by typical 160 nV/√Hz at 1 kHz; critical for low-noise LDO references. |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm), surface-mount, lead-free, RoHS-compliant. Thermal resistance RθJA = 206 °C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (REF) | Reference input | High-impedance node sensing voltage divider output; sets regulation point when current ≤4 µA. |
| Pin 2 (CATHODE) | Shunt current output | Sinks up to 100 mA to ground or return path; connects to optocoupler anode in isolated feedback. |
| Pin 3 (ANODE) | Common return | Typically tied to system ground or power return; serves as voltage reference for REF and cathode current path. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output range | 2.5 V to 36 V - set by external resistive divider; eliminates need for multiple fixed-voltage references. |
| Temperature drift performance | ≤34 mV deviation over −40°C to +125°C - ensures stable regulation in wide-temperature industrial drives. |
| Low output impedance | 0.2 Ω typical - suppresses ripple propagation in closed-loop feedback, improving PSRR in secondary-side regulation. |
| ESD robustness | ±2000 V HBM - withstands handling and board assembly without special ESD precautions. |
| Stability with capacitive loads | Defined boundary curves (Fig. 6-18) - enables reliable design with common output filter caps up to 1 µF. |
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 data center servers. IC Role / Device Role / Timing Role: Shunt reference in optocoupler-coupled feedback loop, adjusting PWM duty cycle via TL431BCDBZR's cathode current. Use Value: ±0.5% Vref tolerance ensures <±1% output voltage accuracy across line/load/temperature, meeting server PSU efficiency standards. |
Use Scenario: Output voltage sensing in 3-phase rectified 400 VAC-to-24 VDC industrial power supplies. IC Role / Device Role / Timing Role: Precision shunt reference establishing regulated 24 V rail; interfaces with TL431BCDBZR's REF pin via 10 kΩ/10 kΩ divider. Use Value: Q-grade thermal stability prevents output drift during extended high-temperature operation in factory-floor enclosures. |
| AC Inverter Drive | Notebook PC Power Adapter |
Use Scenario: Feedback reference for auxiliary 15 V bias supply powering gate drivers in 3 kW variable-frequency motor drives. IC Role / Device Role / Timing Role: TL431BCDBZR regulates auxiliary rail using cathode-sink current into optocoupler LED, closing isolation barrier loop. Use Value: 100 mA sink capability allows direct optocoupler drive without buffer transistor, reducing BOM count and layout area. |
Use Scenario: Output voltage regulation in compact 65 W GaN-based USB-C laptop adapters. IC Role / Device Role / Timing Role: TL431BCDBZR provides 5 V/20 V reference in multi-output flyback controller feedback network. Use Value: Low 2–4 µA reference current minimizes divider power loss, improving light-load efficiency critical for Energy Star compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BQDBZR | Same B-grade accuracy and Q-temp range, but SOT-23-3 package identical to TL431BCDBZR - no pinout or layout change required. | Identical functional use; differs only in part numbering convention (C vs Q suffix indicates same temp grade). | Select TL431BQDBZR only if procurement system requires explicit Q-suffix designation; otherwise TL431BCDBZR is preferred per TI's current ordering nomenclature. |
| TLVH431BQDBVR | Lower 1.24 V reference, 0.5% tolerance, Q-grade, but higher 10 µA reference current and 0.35 Ω impedance. | Suitable for sub-2.5 V rails (e.g., 1.8 V logic supplies); not drop-in for 2.5 V+ applications due to different Vref and higher Iref. | Choose TLVH431BQDBVR only when designing new 1.24 V reference circuits; TL431BCDBZR remains optimal for legacy 2.5 V–36 V adjustable systems. |
Compared with TL431BQDBZR (identical specs, alternate marking) and TLVH431BQDBVR (lower Vref, higher Iref), TL431BCDBZR offers the best balance of 2.5 V baseline, minimal reference current, and proven stability in high-volume power adapter designs.
Availability
TL431BCDBZR is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and notebook PC power adapter designs requiring stable component supply with guaranteed long-term manufacturability.
Supply support for TL431BCDBZR 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 solutions.
TL431BCDBZR belongs to TI's precision shunt reference product line, engineered for high-accuracy, wide-temperature feedback regulation in isolated and non-isolated power supplies across computing, industrial, and automotive markets.
FAQ
What is the reference voltage tolerance of TL431BCDBZR at 25°C?
The TL431BCDBZR has a ±0.5% initial reference voltage tolerance at 25°C, corresponding to a Vref range of 2.483 V to 2.507 V. This B-grade accuracy is specified in Section 6.11 of the TI SLVS543S datasheet and applies strictly to the TL431BCDBZR variant with Q-grade temperature characterization.
Does TL431BCDBZR support operation at 125°C ambient temperature?
Yes, TL431BCDBZR is a Q-grade device characterized for operation from −40°C to +125°C ambient temperature. Its electrical specifications-including Vref deviation ≤34 mV and dynamic impedance ≤0.5 Ω-are guaranteed across this full range per Section 6.13 of the official TI datasheet.
What is the pin configuration of TL431BCDBZR in SOT-23-3 package?
TL431BCDBZR uses the standard TL431 SOT-23-3 pinout: Pin 1 = REF, Pin 2 = CATHODE, Pin 3 = ANODE (top view, notch left). This differs from TL432 variants and must be verified against TI's Pin Configuration diagram (Figure 5-1, DBZ row) to prevent layout errors.
Can TL431BCDBZR replace a Zener diode in voltage regulation circuits?
Yes, TL431BCDBZR is explicitly designed as a superior replacement for Zener diodes in shunt regulation applications. Its 0.2 Ω dynamic impedance, sharp turn-on, and 0.5% Vref accuracy provide tighter regulation, lower temperature drift, and better noise performance than discrete Zeners-especially in feedback networks of switching power supplies.
What is the maximum cathode current rating for TL431BCDBZR?
The TL431BCDBZR supports a continuous cathode current range of 1 mA to 100 mA per Section 6.4 (Recommended Operating Conditions) and Section 6.11 (Electrical Characteristics). Absolute maximum cathode current is ±150 mA, but sustained operation above 100 mA requires thermal derating based on RθJA = 206 °C/W.
TL431BCDBZR 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:
- ±0.5%
- 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
TL431BCDBZR FAQ
1.How can I place an order for TL431BCDBZR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BCDBZR 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 TL431BCDBZR reliable?
The price and inventory of TL431BCDBZR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BCDBZR is usually 5 days.
3.What payment methods are accepted for TL431BCDBZR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BCDBZR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BCDBZR?
TL431BCDBZR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BCDBZR 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 TL431BCDBZR?
For technical support, including TL431BCDBZR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BCDBZR requirements.
6.How does Aetrix verify that TL431BCDBZR is sourced from the original manufacturer or authorized distributors?
All TL431BCDBZR 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 TL431BCDBZR meets industry standards.
7.What is the process for return or replacement of TL431BCDBZR?
All TL431BCDBZR units undergo pre-shipment inspection (PSI). If there is an issue with TL431BCDBZR, 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 TL431BCDBZR part is unused and in its original packaging.
Return procedure for TL431BCDBZR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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