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Texas Instruments TL431BID
- Part No.:
- TL431BID
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431BID.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:10,646
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Product details
Overview
TL431BID from Texas Instruments is a precision programmable shunt voltage reference IC in SOIC-8 package, featuring 0.5% initial reference voltage tolerance at 25°C, adjustable output from 2.495 V to 36 V, and operation across −40°C to 85°C. It delivers 0.2 Ω typical dynamic impedance and supports 1–100 mA sink current, enabling high-accuracy feedback in isolated DC/DC converters and industrial power supplies.
For engineers reviewing the TL431BID datasheet, TL431BID pinout, TL431BID application, or TL431BID equivalent, this page provides verified electrical specifications, thermal performance data, stability boundary conditions for capacitive loads, and real-world implementation guidance for AC/DC and servo drive control designs.
Technical Context
The TL431BID implements a three-terminal adjustable shunt regulator architecture with an internal error amplifier, reference voltage (2.495 V), and output transistor. Its sharp turn-on characteristic and low temperature drift (14 mV over −40°C to 85°C) enable stable regulation without external compensation in most configurations.
It operates as a voltage-controlled current sink: the REF pin senses voltage relative to ANODE, and the CATHODE pin sinks current proportional to the error between sensed voltage and internal reference. This topology replaces Zener diodes in feedback loops of flyback, forward, and buck-derived isolated supplies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V ±12 mV (0.5% tolerance at 25°C); sets precise feedback threshold for power supply regulation |
| Temp Range | −40°C to +85°C (I-grade); ensures reliable operation in industrial ambient environments |
| Dynamic Impedance | 0.2 Ω typical; maintains tight output voltage regulation under varying load/sink-current conditions |
| Sink Current Range | 1 mA to 100 mA; supports wide-range feedback loop gain adjustment and optocoupler drive capability |
| Ref Input Current | 2–4 µA; enables high-impedance resistor-divider networks without significant loading error |
| Output Noise | Low broadband noise (<1 µV/√Hz @ 10 Hz–100 kHz); critical for low-noise analog feedback paths |
| Stability Margin | Validated up to 10 µF capacitive load (at VKA = 5–15 V); simplifies design of low-ESR output filtering |
Pinout & Package
TL431BID is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package with 4.90 mm × 3.90 mm body size and standard 1.27 mm pitch. The package supports surface-mount reflow assembly and provides adequate thermal dissipation (RθJA = 97°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current output node | Connects to primary-side switch node or optocoupler LED anode; sinks regulated current based on REF-ANODE voltage differential |
| ANODE (Pin 2) | Common reference return | Typically tied to system ground or secondary-side common; serves as voltage reference point for REF input |
| REF (Pin 3) | Feedback sense input | High-impedance input comparing external divider voltage to internal 2.495 V reference; determines regulation setpoint |
| NC (Pins 4–8) | No internal connection | Unused pins; must remain unconnected per TI specification to avoid parasitic coupling or latch-up risk |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% Initial Accuracy | Enables <1% total output voltage error in closed-loop power supplies without post-production trimming |
| 14 mV Max Temp Drift | Guarantees ≤0.5% output variation over full −40°C to +85°C range-critical for industrial temperature stability |
| 0.2 Ω Dynamic Impedance | Minimizes load-induced output voltage sag during transient current steps in feedback networks |
| 1–100 mA Sink Capability | Directly drives standard optocouplers (e.g., PC817, SFH615A) without external buffer transistors |
| SOIC-8 Thermal Performance | RθJA = 97°C/W allows ≥500 mW continuous power dissipation at 25°C ambient-sufficient for most bias applications |
Applications
| Rack Server Power | Industrial AC/DC Converter |
|---|---|
Use Scenario: Secondary-side voltage sensing and feedback in 48 V input, 12 V/50 A isolated DC/DC modules. IC Role / Device Role / Timing Role: Precision shunt reference providing error signal to optocoupler-driven PWM controller. Use Value: Maintains ±0.5% output regulation across line/load/temperature with no calibration required. |
Use Scenario: Output voltage regulation in 3-phase rectified 400 VAC-to-24 VDC industrial power supply. IC Role / Device Role / Timing Role: Adjustable reference setting feedback threshold for UC384x-based flyback controller. Use Value: Enables single-BOM support for 12 V, 24 V, and 48 V outputs via resistor divider change only. |
| Servo Drive Control Module | Notebook PC Power Adapter |
Use Scenario: Isolated auxiliary rail regulation (±15 V) for gate drivers and op-amp bias in motor control inverters. IC Role / Device Role / Timing Role: Dual-rail shunt reference generating stable bias voltages referenced to power stage common. Use Value: Eliminates need for dual Zener diodes while improving tempco matching and long-term drift. |
Use Scenario: Primary-side feedback in compact 65 W GaN-based USB-C PD adapter with QR flyback topology. IC Role / Device Role / Timing Role: High-accuracy reference interfacing with digital controller via optocoupler for safety isolation. Use Value: Achieves CoC Tier 2 efficiency compliance by minimizing feedback path error and enabling tighter voltage margins. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBVR | SOT-23-3 package, C-grade (0°C–70°C), same 0.5% tolerance but higher temp drift (6 mV) | Better suited for cost-sensitive consumer adapters where ambient stays below 70°C | Select when board space is constrained and industrial temp range is not required |
| TL431BQDBVR | SOT-23-3 package, Q-grade (−40°C–125°C), identical 0.5% tolerance and 14 mV drift | Required for automotive under-hood or high-temp industrial environments | Choose when extended junction temperature (125°C) and minimal footprint are mandatory |
Compared with TL431CDBVR and TL431BQDBVR, TL431BID offers superior thermal dissipation (97°C/W vs >200°C/W) and mechanical robustness in SOIC-8, making it optimal for high-reliability industrial power designs where sustained 100 mA sink current and PCB-level thermal management are critical.
Availability
TL431BID is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and servo drive control modules requiring stable component supply with guaranteed long-term continuity.
Supply support for TL431BID 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 and embedded processing technologies, with decades of leadership in precision reference and power management ICs.
The TL431 product line was designed specifically for high-accuracy, low-drift voltage regulation in isolated power supply feedback loops-targeting industrial, computing, and telecom infrastructure applications.
FAQ
What is the reference voltage accuracy of TL431BID at 25°C?
The TL431BID features a 0.5% initial reference voltage tolerance at 25°C, corresponding to 2.495 V ±12 mV. This specification is guaranteed per TI's SLVS543S datasheet Section 6.12 (TL431BI electrical characteristics), and applies across the full SOIC-8 package variant of the B-grade device.
Does TL431BID require external compensation for stability?
TL431BID does not require external compensation in most standard configurations. Per Figure 6-18 of the datasheet, it remains stable with up to 10 µF capacitive load at cathode voltages of 5–15 V and sink currents up to 100 mA-enabling direct use with low-ESR ceramic output capacitors in isolated flyback designs.
Can TL431BID replace a Zener diode in existing designs?
Yes, TL431BID is explicitly designed as a high-performance Zener diode replacement. Its sharp turn-on, low dynamic impedance (0.2 Ω), and adjustable 2.495–36 V output make it ideal for on-board regulation, adjustable supplies, and switching power supply feedback-provided the ANODE is grounded and REF is connected via resistive divider.
What is the maximum continuous cathode current for TL431BID?
The TL431BID supports a continuous cathode current range of 1 mA to 100 mA, as specified in Section 6.4 (Recommended Operating Conditions) and validated in Section 6.12. At 100 mA and 25°C ambient, its SOIC-8 package dissipates ~2.5 W, remaining within safe junction temperature limits given RθJA = 97°C/W.
How does TL431BID differ from TL431C or TL431A variants?
TL431BID is the B-grade (0.5% tolerance), I-temperature (−40°C to +85°C) version in SOIC-8. TL431C has looser 2% tolerance and 0°C–70°C range; TL431A offers 1% tolerance. All share identical pinout, electrical architecture, and functional behavior-only accuracy and temperature grade differ.
TL431BID Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tube
- 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 ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TL431BID FAQ
1.How can I place an order for TL431BID through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BID 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 TL431BID reliable?
The price and inventory of TL431BID are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BID is usually 5 days.
3.What payment methods are accepted for TL431BID?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BID transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BID?
TL431BID orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BID 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 TL431BID?
For technical support, including TL431BID datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BID requirements.
6.How does Aetrix verify that TL431BID is sourced from the original manufacturer or authorized distributors?
All TL431BID 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 TL431BID meets industry standards.
7.What is the process for return or replacement of TL431BID?
All TL431BID units undergo pre-shipment inspection (PSI). If there is an issue with TL431BID, 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 TL431BID part is unused and in its original packaging.
Return procedure for TL431BID:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BID Tags
-
TL431AIDBZR
Texas Instruments
-
TL431BQDBZR
Texas Instruments
-
AN431AN-ATRG1
Diodes Incorporated
-
LM4040CYM3-2.5-TR
Microchip Technology
-
LM4040CYM3-4.1-TR
Microchip Technology
-
LM4040EIM3-2.5/NOPB
Texas Instruments
-
AZ431LBNTR-G1
Diodes Incorporated
-
LM4040D20IDBZR
Texas Instruments
-
LM4041DIM3-ADJ/NOPB
Texas Instruments
-
LM4040DIM3X-2.5/NOPB
Texas Instruments
-
LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
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