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Texas Instruments TL431BCDE4
- Part No.:
- TL431BCDE4
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431BCDE4.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,778
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Product details
Overview
TL431BCDE4 from Texas Instruments is a precision programmable shunt voltage reference IC with 0.5% initial tolerance at 25°C, 2.483–2.507 V reference voltage, 6 mV max full-temperature-range deviation (C-grade), 0.2 Ω typical dynamic impedance, and 1–100 mA sink-current capability. It serves as an adjustable voltage reference in secondary-side regulation of flyback SMPSs, replacing Zener diodes in onboard regulation and voltage monitoring circuits.
For engineers reviewing the TL431BCDE4 datasheet, TL431BCDE4 pinout, TL431BCDE4 application, or TL431BCDE4 equivalent, key selection considerations include its SOIC-8 package, C-temp grade (0°C to 70°C), B-grade accuracy, cathode-anode-reference terminal configuration, and compatibility with resistor-divider-based output programming from 2.5 V to 36 V.
Technical Context
The TL431BCDE4 implements a three-terminal adjustable shunt regulator architecture with an internal op-amp and NPN transistor output stage. Its reference input (REF) compares against a stable 2.495 V bandgap-derived threshold, controlling cathode current flow to maintain precise voltage regulation across external resistive feedback networks.
It operates as a two-quadrant device: sinking current from cathode to anode when REF voltage exceeds Vref, with sharp turn-on characteristics and low output impedance (0.2 Ω typ). The SOIC-8 package supports thermal dissipation up to 85°C/W junction-to-ambient, enabling stable operation under 100 mA load conditions within commercial temperature limits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Vref | 2.483–2.507 V at 25°C - defines minimum programmable output voltage and sets accuracy baseline for resistor-divider designs |
| Initial Tolerance | ±0.5% (B grade) - enables high-accuracy voltage setting without trimming in power supply feedback loops |
| Temp Drift (VI(dev)) | 6 mV max over 0°C to 70°C - ensures <±0.025% output variation across commercial temperature range |
| Dynamic Impedance | 0.2 Ω typical - provides low-noise, stiff reference node for sensitive analog circuitry and feedback stability |
| Sink Current Range | 1–100 mA - supports direct drive of optocoupler LEDs or error amplifier inputs in isolated SMPS topologies |
| Reference Input Current | 2–4 µA - minimizes divider resistor power loss and bias error in high-impedance feedback networks |
| Min Cathode Current | 0.4–0.6 mA - establishes lowest stable operating point for regulation; critical for light-load SMPS efficiency |
Pinout & Package
TL431BCDE4 is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package measuring 4.90 mm × 3.90 mm, with standard JEDEC MS-012AC footprint and gull-wing leads. Thermal resistance is RθJA = 85°C/W, supporting continuous operation at up to 100 mA sink current within ambient temperatures up to 70°C.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Cathode | Main current-sink terminal; connects to regulated output node or optocoupler anode in isolated feedback paths |
| 2 | NC | No internal connection - must remain unconnected per TI pinout specification for SOIC-8 variant |
| 3 | NC | No internal connection - electrically isolated; no routing or grounding required |
| 4 | NC | No internal connection - unused pad; no PCB trace or thermal pad connection needed |
| 5 | NC | No internal connection - reserved for future variants; leave floating |
| 6 | NC | No internal connection - not bonded; no electrical function |
| 7 | Anode | Common return path; typically tied to system ground or negative rail in shunt regulator configurations |
| 8 | Ref | High-impedance reference input; connected to resistor divider midpoint to set output voltage via VOUT = Vref × (1 + R1/R2) |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% Initial Accuracy (B Grade) | Enables ±12.5 mV absolute reference error at 2.5 V - eliminates need for post-production calibration in mid-precision supplies |
| Adjustable Output (2.5 V to 36 V) | Supports single-component solution for wide-range DC-DC feedback without discrete Zener arrays or DACs |
| 0.2 Ω Dynamic Impedance | Delivers <1 mV output perturbation under 1 mA load transients - improves transient response in closed-loop regulators |
| Low Reference Input Current (2–4 µA) | Permits use of >1 MΩ feedback dividers - reduces standby power and thermal drift in battery-powered systems |
| Commercial Temp Range (0°C to 70°C) | Validated for reliable operation in office equipment, consumer adapters, and industrial control panels without derating |
Applications
| SMPS Secondary-Side Regulation | Zener Diode Replacement |
|---|---|
|
Use Scenario: Feedback control in isolated flyback converters using optocoupler-coupled error signal to primary-side PWM controller. IC Role / Device Role / Timing Role: Shunt reference providing precise voltage sampling at secondary output, driving optocoupler LED current proportional to output deviation. Use Value: Enables ±1% output regulation across line/load/temperature without magnetic feedback components or digital compensation. |
Use Scenario: Voltage clamping and reference generation in linear regulators, battery chargers, and overvoltage protection circuits. IC Role / Device Role / Timing Role: Programmable shunt regulator replacing fixed-voltage Zener diodes with tighter tolerance and lower dynamic impedance. Use Value: Reduces output voltage error by >5× versus 5% Zeners and improves load regulation by 10× due to 0.2 Ω vs. 10–100 Ω Zener impedance. |
| Voltage Monitoring & Supervision | Adjustable Precision Reference |
|
Use Scenario: Undervoltage lockout (UVLO) and overvoltage detection in microcontroller power domains and FPGA auxiliary rails. IC Role / Device Role / Timing Role: Threshold comparator with integrated reference, comparing monitored rail against resistor-programmed trip point. Use Value: Achieves 0.5% detection accuracy over 0°C–70°C - eliminates external reference ICs and reduces BOM count by one component. |
Use Scenario: Setting precise bias points for op-amps, ADC references, sensor excitation, and DAC output scaling in test equipment and instrumentation. IC Role / Device Role / Timing Role: Stable, low-drift voltage source configured via external resistors to deliver user-defined reference levels. Use Value: Delivers <6 mV total drift over temperature - outperforms most monolithic 2.5 V references in cost-sensitive, non-automotive applications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDR | I-grade (−40°C to 85°C), same 0.5% tolerance and SOIC-8 package; VI(dev) = 14 mV max over full range | Required for extended temperature industrial or automotive body electronics where ambient exceeds 70°C | Select TL431BIDR when operating environment exceeds 70°C but board layout and schematic must remain unchanged |
| TL431CDE4 | C-grade (0°C to 70°C) with 2% initial tolerance (2440–2550 mV); otherwise identical pinout, package, and electrical behavior | Suitable for cost-sensitive applications where ±50 mV reference error is acceptable, e.g., non-critical biasing or coarse monitoring | Choose TL431CDE4 only if system-level testing confirms 2% tolerance meets functional safety and regulation margins |
Compared with TL431BCDE4, TL431BIDR extends temperature coverage at higher drift cost, while TL431CDE4 trades accuracy for cost-neither offers pin-to-pin or functional equivalence without design validation for the target operating envelope.
Availability
TL431BCDE4 is available at Aetrix Electronics and suitable for SMPS feedback design, voltage supervision systems, and precision reference generation requiring stable component supply across commercial temperature environments.
Supply support for TL431BCDE4 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The TL431 product line was designed as a precision, low-cost, three-terminal shunt reference for voltage regulation and monitoring in power management systems-targeting cost-sensitive, high-volume applications where Zener diodes lack accuracy and stability.
FAQ
What is the reference voltage tolerance of TL431BCDE4 at 25°C?
The TL431BCDE4 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a guaranteed 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 official TI datasheet SLVS543P and applies specifically to the C-temp (0°C to 70°C) and B-tolerance variant packaged in SOIC-8.
Does TL431BCDE4 support adjustable output voltages above 2.5 V?
Yes, TL431BCDE4 supports adjustable output voltages from 2.5 V up to 36 V using an external resistor divider network connected between cathode, reference, and anode pins. The output voltage is calculated as VOUT = Vref × (1 + R1/R2), where R1 connects cathode to reference and R2 connects reference to anode. This functionality is explicitly defined in the device description and verified across all TL431x grades.
What is the maximum cathode current rating for TL431BCDE4?
The TL431BCDE4 supports a continuous cathode current range of 1 mA to 100 mA, as specified in the Recommended Operating Conditions (Section 7.4) and Electrical Characteristics tables (Sections 7.11–7.13). Absolute maximum cathode current is ±150 mA, but sustained operation above 100 mA requires thermal derating per the SOIC-8 RθJA = 85°C/W specification.
Is TL431BCDE4 pin-compatible with other TL431 variants in SOIC-8 packages?
Yes, TL431BCDE4 shares identical SOIC-8 pinout (1=CATHODE, 7=ANODE, 8=REF, pins 2–6=NC) with all TL431x and TL432x variants in the D-package, including TL431CDE4, TL431BIDR, and TL431AQDR. Pin compatibility is confirmed in TI's Device Comparison Table and Pin Configuration diagrams for SOIC-8, with NC pins consistently placed across grades and temp ranges.
What is the typical dynamic impedance of TL431BCDE4 and why does it matter?
The TL431BCDE4 has a typical dynamic impedance of 0.2 Ω at frequencies ≤1 kHz and cathode currents from 1 mA to 100 mA. This low value ensures minimal output voltage perturbation during load transients-critical for maintaining regulation stability in feedback loops and reducing noise coupling into sensitive analog nodes like ADC references or op-amp bias points.
TL431BCDE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Bulk
- 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:
- 8-SOIC
TL431BCDE4 FAQ
1.How can I place an order for TL431BCDE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BCDE4 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 TL431BCDE4 reliable?
The price and inventory of TL431BCDE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BCDE4 is usually 5 days.
3.What payment methods are accepted for TL431BCDE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BCDE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BCDE4?
TL431BCDE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BCDE4 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 TL431BCDE4?
For technical support, including TL431BCDE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BCDE4 requirements.
6.How does Aetrix verify that TL431BCDE4 is sourced from the original manufacturer or authorized distributors?
All TL431BCDE4 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 TL431BCDE4 meets industry standards.
7.What is the process for return or replacement of TL431BCDE4?
All TL431BCDE4 units undergo pre-shipment inspection (PSI). If there is an issue with TL431BCDE4, 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 TL431BCDE4 part is unused and in its original packaging.
Return procedure for TL431BCDE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BCDE4 Tags
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