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Diodes Incorporated TL431BW5-7
- Part No.:
- TL431BW5-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
TL431BW5-7.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT25
- Quantity:
- Payment:
- Shipping:
Inventory:974
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Product details
Overview
TL431BW5-7 from Diodes Incorporated is a precision adjustable shunt voltage regulator in SOT25 package, featuring 2.495 V ±0.5% reference voltage tolerance at 25°C, 1 mA to 100 mA cathode sink current capability, and 0.2 Ω typical dynamic output impedance. It replaces discrete Zener diodes in feedback loops of isolated DC-DC converters and linear power supplies requiring tight regulation over -40°C to +125°C.
For engineers reviewing the TL431BW5-7 datasheet, TL431BW5-7 pinout, TL431BW5-7 application, or TL431BW5-7 equivalent, this part supports design of stable, low-noise voltage references with programmable output from 2.5 V to 36 V using two external resistors - critical for opto-coupler-based feedback, overvoltage protection, and precision comparator thresholds.
Technical Context
The TL431BW5-7 operates as a three-terminal shunt regulator with internal bandgap reference, error amplifier, and NPN output stage. Its reference input (REF) senses voltage via external resistor divider, while cathode (KA) sinks current to maintain regulated voltage across the anode–cathode path.
It delivers 14–34 mV reference voltage deviation over -40°C to +125°C, −1.4 to −2.7 mV/V cathode voltage sensitivity, and 0.05–0.5 µA off-state cathode current at 36 V - enabling high-accuracy, low-power regulation without external compensation under defined capacitive load conditions (e.g., stable with 5 nF–20 nF).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V ±0.5% at 25°C - enables precise 2.5 V threshold setting with minimal calibration overhead |
| Cathode Current Range | 1 mA to 100 mA - supports direct regulation of medium-current loads without external pass transistor |
| Dynamic Output Impedance | 0.2 Ω typical - ensures <1 mV output shift per 1 mA load change, critical for ripple-sensitive references |
| Temperature Range | -40°C to +125°C - validated for automotive cabin and industrial control environments |
| Output Voltage Range | 2.5 V to 36 V - programmable via R1/R2 divider, eliminating need for multiple fixed-voltage regulators |
| Reference Input Current | 1–4 µA - minimizes divider resistor power loss and thermal drift in high-impedance sensing networks |
| Thermal Resistance (J-A) | 250°C/W (SOT25) - allows 500 mW max power dissipation at 25°C ambient before reaching 150°C junction limit |
Pinout & Package
SOT25 package: 5-pin surface-mount plastic package with exposed thermal pad (pin 4), optimized for thermal performance in space-constrained power management layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Anode) | Current return path / ground reference | Connected to system ground or lowest potential node; defines reference for cathode voltage measurement |
| 2 (Anode) | Dual anode terminal | Internally tied to Pin 1; provides redundant ground connection and improved thermal conduction |
| 3 (Ref) | Reference input | High-impedance input monitoring divided-down output voltage; regulates when voltage equals 2.495 V |
| 4 (NC) | No connect | Thermal pad - must be soldered to PCB copper pour for thermal management; not electrically connected |
| 5 (Cathode) | Regulated output sink | Sinks current to maintain VKA = VREF × (1 + R1/R2); connects to feedback node of isolated flyback or forward converter |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% initial reference tolerance (B grade) | Reduces or eliminates post-manufacturing trimming in voltage-setting circuits for medical and test equipment |
| Low 0.2 Ω dynamic output impedance | Maintains regulation stability under fast transient load steps in SMPS feedback paths |
| −40°C to +125°C operating range | Enables use in under-hood automotive modules and industrial motor drives without derating |
| 100 mA continuous cathode current | Directly drives optocoupler LEDs in isolated 5 W–15 W DC-DC converters without auxiliary bias winding |
| Low 1–4 µA reference input current | Permits use of >1 MΩ divider resistors, minimizing standby power in battery-backed systems |
Applications
| Optocoupler-Based Feedback Loop | Overvoltage Protection Circuit |
|---|---|
|
Use Scenario: Isolated flyback converter with primary-side regulation via secondary-side TL431 and PC817 optocoupler. IC Role / Device Role / Timing Role: Shunt regulator providing precise 2.5 V reference to optocoupler LED anode; controls feedback current proportional to output voltage. Use Value: Enables ±1% output voltage accuracy across line/load/temperature, replacing less stable Zener-based solutions. |
Use Scenario: Monitoring 12 V automotive battery rail for overvoltage events above 15.5 V during alternator surge. IC Role / Device Role / Timing Role: Adjustable shunt reference comparing scaled battery voltage against 2.495 V; triggers latch-off via comparator when threshold exceeded. Use Value: Programmable trip point with <±50 mV hysteresis achievable using hysteresis resistor, preventing chatter during marginal overvoltage. |
| Precision Comparator Threshold | Adjustable Series Regulator |
|
Use Scenario: Temperature-compensated undervoltage lockout (UVLO) in FPGA power sequencing with 0.8 V core rail. IC Role / Device Role / Timing Role: Reference source for LM393 comparator; sets accurate 0.75 V trip point via resistor divider from 3.3 V supply. Use Value: Achieves ±10 mV trip accuracy over temperature, ensuring reliable startup without false triggering. |
Use Scenario: Low-noise 5 V series regulator for analog sensor signal chain powered from 12 V unregulated input. IC Role / Device Role / Timing Role: Precision reference driving P-channel MOSFET gate; adjusts pass element to maintain constant 5 V output. Use Value: Delivers <10 µV RMS noise and <0.01%/V line regulation - superior to standard 78L05 in noise-sensitive applications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBVR (TI, SOT-23) | Same 2.495 V ±0.5%, but SOT-23 package (330 mW PD, 380°C/W θJA) vs. SOT25 (500 mW, 250°C/W) | Limited to ≤60 mA continuous cathode current due to thermal constraints; unsuitable for >10 mA optocoupler drive at high ambient | Select only if board space is constrained and thermal margin ≥25°C is guaranteed |
| AS431BMTR-E1 (Diodes Inc., SOT25) | Same pinout and 0.5% tolerance, but higher 1.5 µA max IREF (vs. 4 µA typ.) and 0.3 Ω ZKA | Lower reference current improves divider efficiency in ultra-low-power IoT sensors; slightly reduced PSRR | Prefer for battery-powered applications where IREF < 2 µA is required and 0.1 Ω ZKA margin is acceptable |
Compared with TL431BW5-7, TL431BIDBVR trades thermal performance for footprint reduction, while AS431BMTR-E1 prioritizes ultra-low reference current at minor impedance cost - making TL431BW5-7 optimal for thermally demanding, medium-current feedback designs.
Availability
TL431BW5-7 is available at Aetrix Electronics and suitable for isolated DC-DC converters, overvoltage protection circuits, and precision comparator threshold generation requiring stable component supply across automotive, industrial, and telecom power systems.
Supply support for TL431BW5-7 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection solutions for industrial and automotive markets.
The TL431 product line delivers precision shunt regulation for feedback, protection, and reference applications - designed specifically to replace Zener diodes with tighter tolerance, lower noise, and wider temperature operation.
FAQ
What is the minimum cathode current required for regulation in TL431BW5-7?
The TL431BW5-7 requires a minimum cathode current of 0.4 mA to 0.7 mA (typical 0.5 mA) to maintain regulation. This value is specified at VKA = VREF and ensures stable operation when used with high-value feedback dividers or low-power optocouplers.
Can TL431BW5-7 be used with capacitive loads, and what are the stability limits?
Yes - TL431BW5-7 is stable with capacitive loads of 5 nF to 20 nF, or >300 nF, or <50 pF. Instability may occur between 50 pF and 5 nF or 20 nF and 300 nF. For most SMPS feedback applications, 10 nF ceramic capacitors on the cathode provide optimal phase margin and noise filtering.
How does the SOT25 package improve thermal performance over SOT23 for TL431BW5-7?
The SOT25 package features dual anode pins and an exposed thermal pad (Pin 4), reducing junction-to-ambient thermal resistance to 250°C/W versus 380°C/W for SOT23. This allows 500 mW power dissipation at 25°C ambient - supporting 100 mA cathode current in compact layouts without forced air cooling.
Is TL431BW5-7 RoHS-compliant and halogen-free?
Yes - TL431BW5-7 is fully RoHS-compliant (2011/65/EU), lead-free, and halogen/antimony-free ("Green" per Diodes Inc. definition: <900 ppm Br, <900 ppm Cl, <1000 ppm Sb). Compliance is verified per Diodes' quality documentation AP02001 and lead-free roadmap.
TL431BW5-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- SC-74A, SOT-753
- 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:
- 700 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-25
TL431BW5-7 FAQ
1.How can I place an order for TL431BW5-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BW5-7 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 TL431BW5-7 reliable?
The price and inventory of TL431BW5-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BW5-7 is usually 5 days.
3.What payment methods are accepted for TL431BW5-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BW5-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BW5-7?
TL431BW5-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BW5-7 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 TL431BW5-7?
For technical support, including TL431BW5-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BW5-7 requirements.
6.How does Aetrix verify that TL431BW5-7 is sourced from the original manufacturer or authorized distributors?
All TL431BW5-7 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 TL431BW5-7 meets industry standards.
7.What is the process for return or replacement of TL431BW5-7?
All TL431BW5-7 units undergo pre-shipment inspection (PSI). If there is an issue with TL431BW5-7, 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 TL431BW5-7 part is unused and in its original packaging.
Return procedure for TL431BW5-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BW5-7 Tags
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