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Texas Instruments TL431BQD
- Part No.:
- TL431BQD
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431BQD.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,551
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Product details
Overview
TL431BQD from Texas Instruments is a precision programmable shunt voltage reference IC with 0.5% initial tolerance at 25°C, −40°C to +125°C operating temperature range, and 2.483–2.507 V reference voltage. It delivers 1–100 mA sink current capability, 0.2 Ω typical dynamic impedance, and supports adjustable output from 2.5 V to 36 V using two external resistors - widely deployed in industrial AC/DC power supplies and servo drive control modules.
For engineers reviewing the TL431BQD datasheet, TL431BQD pinout, TL431BQD application, or TL431BQD equivalent, this page provides verified electrical specifications, thermal performance data, SOT-23-3 package mapping, functional pin roles, and validated alternative parts for automotive-grade feedback loop design and high-reliability regulation circuits.
Technical Context
The TL431BQD implements a three-terminal adjustable shunt regulator architecture with an internal precision bandgap reference, error amplifier, and NPN output stage. Its sharp turn-on characteristic and low 0.2 Ω dynamic impedance enable stable closed-loop regulation without external compensation in most configurations.
Designed for Q-temp (−40°C to +125°C) operation, it exhibits ≤34 mV total reference voltage deviation over temperature and maintains <2.5 µA reference input current drift - making it suitable for isolated feedback paths where thermal stability and low bias current are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VREF) | 2.483–2.507 V at 25°C; enables precise 2.5 V–36 V adjustable output via resistor divider |
| Initial Tolerance | ±0.5% at 25°C (B grade); ensures tight voltage setpoint accuracy without trimming |
| Operating Temperature | −40°C to +125°C (Q grade); qualified for under-hood automotive and industrial environments |
| Sink Current Range | 1–100 mA; supports direct interface with optocoupler LEDs and error amplifier outputs |
| Dynamic Impedance | 0.2 Ω typical; minimizes output voltage variation under load transients |
| Reference Input Current | 2–4 µA; low bias current reduces divider power loss and improves efficiency |
| Temp Drift (VI(dev)) | ≤34 mV over full temperature range; ensures stable regulation across thermal extremes |
Pinout & Package
SOT-23-3 (DBZ) package: 2.90 mm × 1.30 mm body size, surface-mount, lead-free, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1: REF | Reference input | Threshold node connected to resistor divider midpoint; sets regulated output voltage |
| Pin 2: CATHODE | Shunt current output | Current-sinking terminal tied to primary-side controller or optocoupler anode |
| Pin 3: ANODE | Common return | Typically grounded or connected to secondary-side common; defines reference potential |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output range | 2.5 V to 36 V via two external resistors - eliminates need for multiple fixed references |
| Low output noise | Sub-20 µVRMS (0.1–10 Hz); preserves signal integrity in precision feedback loops |
| Sharp turn-on characteristic | Fast response with minimal overshoot - enables stable regulation without external compensation |
| High ESD robustness | ±2000 V HBM - withstands handling and board-level electrostatic discharge events |
| Thermal stability | ≤34 mV VREF deviation over −40°C to +125°C - ensures consistent performance in harsh environments |
Applications
| Industrial AC/DC Power Supplies | Rack Server Power |
|---|---|
Use Scenario: Secondary-side voltage regulation in isolated flyback converters delivering 12 V/48 V to server backplanes. IC Role / Device Role / Timing Role: Precision shunt reference providing feedback to optocoupler-driven primary-side PWM controller. Use Value: Enables ±1% output regulation across line/load/temperature with no trimming required. |
Use Scenario: Multi-rail DC-DC converter supervision in 1U rack servers requiring redundant 3.3 V/5 V/12 V outputs. IC Role / Device Role / Timing Role: Reference element in isolated feedback path for digital power management ICs. Use Value: Maintains stable regulation during rapid load transients and ambient temperature swings up to 70°C. |
| Servo Drive Control Module | AC Inverter & VF Drives |
Use Scenario: Voltage sensing and current limit threshold generation in motor gate driver auxiliary supplies. IC Role / Device Role / Timing Role: Adjustable reference setting analog comparator trip points for overcurrent protection. Use Value: Delivers 0.5% accuracy over −40°C to +125°C, ensuring reliable fault detection across operating envelope. |
Use Scenario: Feedback regulation of DC bus voltage in variable-frequency inverters for HVAC and pump drives. IC Role / Device Role / Timing Role: Shunt reference stabilizing isolated error amplifier output feeding PWM modulator. Use Value: Supports 36 V max cathode voltage rating and 100 mA sink capability for high-power inverter designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBZR | I-grade (−40°C to +85°C), same SOT-23-3 package and 0.5% tolerance | Limited to commercial/industrial ambient; not qualified for extended automotive temperature range | Select when full Q-temp range is unnecessary and cost optimization is prioritized |
| TLVH431BQDBVR | Lower 1.24 V reference, 0.5% tolerance, Q-temp rated, SOT-23-3 package | Enables sub-2.5 V regulation; requires different resistor scaling; higher IREF (10 µA) | Choose for low-voltage feedback paths where 1.24 V reference improves resolution and headroom |
Compared with TL431BQD, TL431BIDBZR trades extended temperature capability for lower cost in non-automotive systems, while TLVH431BQDBVR offers a lower reference voltage ideal for battery-powered or low-input-voltage applications - both require no PCB layout changes but differ in voltage range and thermal qualification.
Availability
TL431BQD is available at Aetrix Electronics and suitable for industrial AC/DC power supplies, servo drive control modules, and AC inverter & VF drives requiring stable component supply with guaranteed long-term sourcing.
Supply support for TL431BQD 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 expertise in precision reference design and automotive-qualified components.
The TL431 product line delivers highly stable, adjustable shunt references optimized for isolated feedback loops in power conversion systems - targeting industrial, automotive, and telecom infrastructure applications demanding high accuracy and reliability.
FAQ
What is the reference voltage tolerance of TL431BQD at 25°C?
The TL431BQD has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 2.483–2.507 V range. This B-grade accuracy is specified in Section 6.13 of the TI SLVS543S datasheet and applies across the full Q-temp operating range when used within recommended conditions. The TL431BQD achieves this tolerance without external trimming.
What package type does TL431BQD use, and what are its dimensions?
The TL431BQD uses the SOT-23-3 (DBZ) package with nominal body dimensions of 2.90 mm × 1.30 mm. Pin 1 is REF, Pin 2 is CATHODE, and Pin 3 is ANODE - confirmed in Figure 5-1 and Table 5-1 of the TI datasheet. This compact surface-mount package supports automated assembly and high-density PCB layouts.
Can TL431BQD replace a Zener diode in feedback circuits?
Yes, the TL431BQD is explicitly designed as a superior replacement for Zener diodes in feedback circuits. Its active error amplifier delivers sharper turn-on, lower dynamic impedance (0.2 Ω vs typical Zener's >10 Ω), and tighter voltage tolerance (±0.5% vs ±5%+ for Zeners). TI's datasheet states it is "an excellent replacement for Zener diodes" in on-board regulation and switching power supplies.
What is the maximum cathode voltage rating for TL431BQD?
The TL431BQD has a maximum cathode voltage (VKA) rating of 37 V absolute maximum and 36 V recommended operating maximum, referenced to the ANODE pin. This allows safe operation in 24 V and 36 V industrial bus systems and supports wide-range adjustable outputs up to 36 V using external resistors.
Does TL431BQD support operation across the full automotive temperature range?
Yes, TL431BQD is Q-grade qualified for operation from −40°C to +125°C, meeting automotive under-hood temperature requirements. Its reference voltage deviation is limited to ≤34 mV over this full range (Section 6.13), and it is listed in TI's device comparison table as Q-temp rated - confirming suitability for automotive powertrain and body electronics applications.
TL431BQD 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:
- 700 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TL431BQD FAQ
1.How can I place an order for TL431BQD through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BQD 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 TL431BQD reliable?
The price and inventory of TL431BQD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BQD is usually 5 days.
3.What payment methods are accepted for TL431BQD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BQD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BQD?
TL431BQD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BQD 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 TL431BQD?
For technical support, including TL431BQD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BQD requirements.
6.How does Aetrix verify that TL431BQD is sourced from the original manufacturer or authorized distributors?
All TL431BQD 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 TL431BQD meets industry standards.
7.What is the process for return or replacement of TL431BQD?
All TL431BQD units undergo pre-shipment inspection (PSI). If there is an issue with TL431BQD, 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 TL431BQD part is unused and in its original packaging.
Return procedure for TL431BQD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BQD Tags
-
TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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AN431AN-ATRG1
Diodes Incorporated
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LM4040CYM3-2.5-TR
Microchip Technology
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LM4040CYM3-4.1-TR
Microchip Technology
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LM4040EIM3-2.5/NOPB
Texas Instruments
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AZ431LBNTR-G1
Diodes Incorporated
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LM4040D20IDBZR
Texas Instruments
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LM4041DIM3-ADJ/NOPB
Texas Instruments
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LM4040DIM3X-2.5/NOPB
Texas Instruments
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LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
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