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Texas Instruments TL431BCDBVRE4
- Part No.:
- TL431BCDBVRE4
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
TL431BCDBVRE4.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,753
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Product details
Overview
TL431BCDBVRE4 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 (B grade), 2.483–2.507 V reference voltage, 6 mV max full-range temperature drift (C-temp grade), 0.2 Ω typical dynamic impedance, and 1–100 mA sink-current capability. It serves as an adjustable voltage reference or Zener diode replacement in secondary-side regulation of flyback SMPSs.
For engineers reviewing the TL431BCDBVRE4 datasheet, TL431BCDBVRE4 pinout, TL431BCDBVRE4 application, or TL431BCDBVRE4 equivalent, key selection criteria include reference accuracy over temperature, cathode current range, dynamic impedance, thermal stability for closed-loop feedback, and SOT-23-3 footprint compatibility in space-constrained power designs.
Technical Context
The TL431BCDBVRE4 implements a three-terminal adjustable shunt regulator architecture with an internal op-amp and NPN transistor output stage. Its REF pin senses voltage relative to ANODE, triggering precise cathode current sinking when the divider voltage exceeds Vref.
It operates across 0°C to 70°C (C-grade), supports cathode voltages from Vref up to 36 V, and maintains regulation with minimum cathode current of 0.4 mA. The device exhibits low output noise and sharp turn-on characteristics, enabling stable operation in high-gain feedback paths without external compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (Vref) | 2.483–2.507 V at 25°C - defines precision setpoint for external resistor divider |
| Initial Tolerance | ±0.5% (B grade) - enables tight output voltage control in regulated supplies |
| Temp Drift (VI(dev)) | ≤6 mV (0°C to 70°C) - ensures <0.0025%/°C stability for industrial ambient operation |
| Cathode Current Range | 1–100 mA - supports direct feedback sinking in 5–24 V SMPS outputs |
| Dynamic Impedance | 0.2 Ω typical - minimizes AC error in feedback loop under load transients |
| Min Cathode Current (Imin) | 0.4 mA - lowest current needed to maintain regulation; critical for light-load stability |
| Ref Input Current (Iref) | 2–4 µA - ultra-low bias current reduces divider power loss and ratio error |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm body), surface-mount, lead-free, RoHS-compliant. Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current output node | Connects to SMPS transformer secondary or voltage divider top; sinks regulated current |
| REF (Pin 2) | Reference input threshold | Senses voltage divider midpoint; triggers regulation when ≥Vref relative to ANODE |
| ANODE (Pin 3) | Common return/reference ground | Typically tied to system ground or power supply return; defines reference potential for REF pin |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output Voltage | 2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-voltage references |
| Sharp Turn-On Characteristic | Active output circuitry enables fast, clean regulation transition - improves transient response in feedback loops |
| Low Output Noise | Enables use in noise-sensitive analog monitoring and precision ADC reference applications |
| 0.2-Ω Output Impedance | Reduces voltage error under varying cathode current - critical for stable closed-loop performance |
| Zener Replacement Capability | Replaces discrete Zener diodes with superior accuracy, tempco, and sink-current linearity |
Applications
| Secondary-Side Regulation | Zener Diode Replacement |
|---|---|
|
Use Scenario: Isolated flyback converter with optocoupler feedback loop. IC Role / Device Role / Timing Role: Shunt reference on secondary side sets precise output voltage threshold; controls optocoupler LED current. Use Value: Enables ±1% output regulation over line/load/temperature without primary-side sensing complexity. |
Use Scenario: Low-power linear regulator or voltage clamp in microcontroller I/O protection. IC Role / Device Role / Timing Role: Precision shunt element replacing 2.5–36 V Zener diodes with tighter tolerance and lower tempco. Use Value: Reduces voltage drift from ±5% (Zener) to ±0.5%, improving system-level accuracy and reliability. |
| Voltage Monitoring | Comparator with Integrated Reference |
|
Use Scenario: Overvoltage detection circuit for battery management or DC bus supervision. IC Role / Device Role / Timing Role: Adjustable threshold reference feeding comparator input; ANODE tied to monitored rail. Use Value: Configurable trip point (e.g., 12.5 V via 5:1 divider) with <6 mV drift over 0–70°C ambient. |
Use Scenario: Window comparator or undervoltage lockout (UVLO) in power sequencers. IC Role / Device Role / Timing Role: Provides stable internal reference for comparator hysteresis or threshold setting. Use Value: Eliminates external reference IC, reducing BOM count while maintaining 0.5% threshold accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBVRE4 | Same electrical specs but rated for −40°C to 85°C (I-grade); VI(dev) ≤14 mV | Required for extended-temperature industrial or automotive under-hood use | Select when operating ambient exceeds 70°C or requires wider temp range compliance |
| TLVH431BQDBVR | Lower Vref (1.24 V), higher Iref (100 nA typ), 0.1 Ω impedance, Q-grade (−40°C to 125°C) | Better suited for low-voltage systems (<3.3 V) and ultra-low-power monitoring | Choose for 1.24 V reference needs, sub-µA bias, or 125°C operation - not drop-in compatible |
Compared with TL431BCDBVRE4, TL431BIDBVRE4 extends temperature range at cost of higher drift, while TLVH431BQDBVR offers lower reference voltage and bias current but requires redesign of resistor divider and layout due to different Vref and pinout.
Availability
TL431BCDBVRE4 is available at Aetrix Electronics and suitable for flyback SMPS regulation, voltage monitoring circuits, Zener replacement designs, and comparator reference applications requiring stable component supply and long-term manufacturability.
Supply support for TL431BCDBVRE4 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 company delivering analog and embedded processing solutions, with leadership in power management, signal chain, and precision analog components.
The TL431 product line delivers precision programmable shunt references for voltage regulation, feedback, and monitoring in power converters, industrial controls, and test equipment - designed for accuracy, stability, and broad temperature operation.
FAQ
What is the reference voltage tolerance of TL431BCDBVRE4 at 25°C?
The TL431BCDBVRE4 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a Vref range of 2.483 V to 2.507 V under specified test conditions (VKA = Vref, IKA = 10 mA). This B-grade accuracy is confirmed in Section 7.11 of the SLVS543P datasheet and applies specifically to the C-temp (0°C to 70°C) version in SOT-23-3 packaging.
Does TL431BCDBVRE4 support operation above 70°C?
No, TL431BCDBVRE4 is characterized for operation from 0°C to 70°C only (C-grade). For operation up to 85°C or 125°C, TI offers TL431BIDBVRE4 (I-grade) or TL431BQDBVRE4 (Q-grade), respectively. Using TL431BCDBVRE4 beyond 70°C violates recommended operating conditions and may result in increased VI(dev) and reduced reliability.
What is the minimum cathode current required for regulation in TL431BCDBVRE4?
The TL431BCDBVRE4 requires a minimum cathode current (Imin) of 0.4 mA to maintain regulation, as specified in Section 7.11 of the datasheet. Below this level, the device may exit regulation mode, causing output voltage to rise uncontrollably - critical for light-load stability in flyback converters.
Can TL431BCDBVRE4 be used as a direct replacement for a 2.5-V Zener diode?
Yes, TL431BCDBVRE4 functions as a precision Zener replacement: connect ANODE to ground, REF to cathode via resistor divider, and CATHODE to supply rail. Its 0.5% tolerance, 6 mV temp drift, and 0.2 Ω impedance outperform typical 5% Zeners, but require two external resistors to set voltage - unlike a single-pin Zener.
What is the dynamic impedance specification for TL431BCDBVRE4 and why does it matter?
TL431BCDBVRE4 has a typical dynamic impedance of 0.2 Ω (max 0.5 Ω) at frequencies ≤1 kHz and cathode currents from 1 mA to 100 mA. This low value ensures minimal AC voltage error during load transients, directly improving regulation accuracy and loop stability in SMPS feedback networks where the TL431BCDBVRE4 resides.
TL431BCDBVRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- SC-74A, SOT-753
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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-23-5
TL431BCDBVRE4 FAQ
1.How can I place an order for TL431BCDBVRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BCDBVRE4 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 TL431BCDBVRE4 reliable?
The price and inventory of TL431BCDBVRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BCDBVRE4 is usually 5 days.
3.What payment methods are accepted for TL431BCDBVRE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BCDBVRE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BCDBVRE4?
TL431BCDBVRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BCDBVRE4 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 TL431BCDBVRE4?
For technical support, including TL431BCDBVRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BCDBVRE4 requirements.
6.How does Aetrix verify that TL431BCDBVRE4 is sourced from the original manufacturer or authorized distributors?
All TL431BCDBVRE4 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 TL431BCDBVRE4 meets industry standards.
7.What is the process for return or replacement of TL431BCDBVRE4?
All TL431BCDBVRE4 units undergo pre-shipment inspection (PSI). If there is an issue with TL431BCDBVRE4, 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 TL431BCDBVRE4 part is unused and in its original packaging.
Return procedure for TL431BCDBVRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BCDBVRE4 Tags
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