My Inquiry
My Account
Texas Instruments TL431BQDBZT
- Part No.:
- TL431BQDBZT
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431BQDBZT.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,014
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
TL431BQDBZT from Texas Instruments is a precision programmable shunt voltage reference in SOT-23-3 package, delivering 2.495 V nominal reference voltage with ±0.5% initial tolerance at 25°C, 14–34 mV total temperature drift over −40°C to +125°C, and 0.2 Ω typical dynamic impedance. It operates as an adjustable feedback element in isolated DC/DC converters and industrial power supplies.
For engineers reviewing the TL431BQDBZT datasheet, TL431BQDBZT pinout, TL431BQDBZT application, or TL431BQDBZT equivalent, key selection criteria include automotive-grade temperature range (−40°C to 125°C), low output noise, sink-current capability up to 100 mA, and compatibility with standard resistor-divider feedback networks for output voltage programming from 2.5 V to 36 V.
Technical Context
The TL431BQDBZT implements a precision bandgap-based error amplifier with internal reference and output transistor in a three-terminal shunt topology. Its REF pin senses voltage relative to ANODE, triggering cathode current modulation to maintain regulation across wide load and line variations.
Designed for high-stability closed-loop feedback, it features sharp turn-on characteristics and supports stable operation with capacitive loads up to 1 µF when properly compensated-critical for flyback and forward converter secondary-side regulation where isolation and accuracy are mandatory.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V (nominal); enables precise 2.5 V–36 V output programming via external resistors |
| Initial Tolerance | ±0.5% at 25°C (B grade); ensures tight output voltage accuracy without trimming |
| Temp Range | −40°C to +125°C (Q grade); qualified for under-hood automotive and industrial environments |
| Dynamic Impedance | 0.2 Ω typical; maintains stable regulation under fast load transients |
| Sink Current Range | 1 mA to 100 mA; supports direct drive of optocoupler LEDs in isolated SMPS feedback paths |
| Output Noise | Low broadband noise; minimizes jitter in voltage-controlled oscillator (VCO) biasing and precision DAC references |
| Ref Input Current | 2–4 µA; enables high-impedance resistor dividers without significant loading error |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm), surface-mount, thermally efficient for power regulation applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1: REF | Reference input | Senses voltage divider output; regulates when voltage equals internal 2.495 V reference |
| Pin 2: CATHODE | Shunt current output | Sinks current to adjust feedback loop; connects to optocoupler LED anode in isolated converters |
| Pin 3: ANODE | Common return | Typically tied to system ground or power supply return; serves as voltage reference point for REF |
Key Features
| Feature | Design Value |
|---|---|
| Precision bandgap reference | 2.495 V ±0.5% at 25°C enables <±1% output voltage accuracy in regulated power supplies |
| Wide operating temperature | −40°C to +125°C rating supports automotive engine control units and industrial motor drives |
| Low dynamic impedance | 0.2 Ω typical ensures minimal output voltage deviation during 10–100 mA load steps |
| Adjustable output range | Programmable from 2.5 V to 36 V using two external resistors-no dedicated IC required |
| Optocoupler-compatible sink | 100 mA max cathode current directly drives PC817/PC817x-series optocouplers without buffer stages |
Applications
| Rack Server Power | Industrial AC/DC Converter |
|---|---|
Use Scenario: Secondary-side voltage sensing in 48 V input, 12 V/50 A isolated DC/DC modules for data center servers. IC Role / Device Role / Timing Role: Shunt reference providing feedback to optocoupler, closing regulation loop across isolation barrier. Use Value: ±0.5% reference tolerance ensures output stays within ±1% spec across temperature, improving PSR and reducing need for post-regulation LDOs. | Use Scenario: Output voltage regulation in 3-phase rectified 400 VAC-to-24 VDC industrial power supply. IC Role / Device Role / Timing Role: Precision shunt reference in TL431-based feedback network controlling PWM duty cycle of UCC28070 controller. Use Value: 14–34 mV total drift over −40°C to +125°C maintains <±2% output stability without calibration, extending service life in harsh enclosures. |
| AC Inverter Drive | Servo Drive Control Module |
Use Scenario: DC bus voltage monitoring and overvoltage protection threshold in 7.5 kW variable-frequency drive. IC Role / Device Role / Timing Role: Programmable reference setting trip point for comparator-driven shutdown circuit. Use Value: Adjustable 2.5–36 V range allows single BOM part to support multiple bus voltages (380 V, 690 V) via resistor change-reducing inventory. | Use Scenario: Isolated auxiliary supply regulation (±15 V, ±5 V) for gate drivers and analog signal conditioning in servo amplifier PCB. IC Role / Device Role / Timing Role: Primary shunt reference in multi-output flyback transformer secondary winding feedback network. Use Value: Low 0.2 Ω dynamic impedance prevents cross-regulation coupling between ±15 V rails, improving encoder signal integrity and current loop accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBZR | Same B-grade accuracy and Q-temp rating, but in SOT-23-5 package with NC pin; higher thermal resistance (206°C/W vs 52°C/W) | Requires PCB layout change; less optimal for high-power dissipation (>300 mW) due to lower thermal performance | Select only if SOT-23-5 footprint is standardized in design and thermal margin exceeds 20°C |
| MAX6008BEUR+T | Fixed 2.5 V output, ±0.2% initial accuracy, 20 ppm/°C tempco, 10 µA max quiescent current | Not adjustable; unsuitable for >2.5 V outputs or resistor-programmed topologies; lower power consumption | Prefer for ultra-low-power sensor nodes or fixed-voltage biasing where 2.5 V suffices and accuracy > TL431BQDBZT is required |
Compared with TL431BIDBZR and MAX6008BEUR+T, TL431BQDBZT offers unique adjustability across 2.5–36 V, automotive temperature qualification, and proven robustness in high-noise power-conversion feedback loops-making it the preferred choice for isolated SMPS designs requiring flexibility and reliability.
Availability
TL431BQDBZT is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and servo drive control modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL431BQDBZT 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, embedded processing, and power management technologies, with decades of leadership in precision reference and power ICs.
The TL431 product line was designed specifically for high-accuracy, low-drift shunt regulation in isolated and non-isolated power supplies-targeting industrial, automotive, and telecom infrastructure applications demanding long-term stability and wide temperature operation.
FAQ
What is the reference voltage tolerance of TL431BQDBZT at 25°C?
The TL431BQDBZT has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a nominal 2.495 V output with minimum 2.483 V and maximum 2.507 V. This B-grade accuracy is specified in Section 6.13 of the TI SLVS543S datasheet and applies exclusively to the TL431BQDBZT variant with Q-temp and SOT-23-3 packaging.
Does TL431BQDBZT support operation across the full automotive temperature range?
Yes, TL431BQDBZT is rated for operation from −40°C to +125°C (Q grade), meeting AEC-Q100 stress test requirements for automotive under-hood applications. Its 14–34 mV total reference voltage deviation over this range is verified per TI's electrical characteristics table for TL431BQ devices, making it suitable for engine control, battery management, and ADAS power supplies.
Can TL431BQDBZT be used to regulate output voltages above 2.5 V?
Yes, TL431BQDBZT is fully adjustable from 2.5 V to 36 V using two external resistors in a standard voltage-divider configuration connected to the REF pin. The device's internal 2.495 V reference compares against the divided output voltage, enabling precise programmability without additional ICs-confirmed in the Functional Description and Typical Applications sections of the TI datasheet.
What is the maximum cathode sink current supported by TL431BQDBZT?
TL431BQDBZT supports continuous cathode sink current from 1 mA to 100 mA, as specified in Recommended Operating Conditions (Section 6.4) and Absolute Maximum Ratings (Section 6.1). This range allows direct interfacing with common optocouplers like PC817 (IF = 5–20 mA) and supports higher-current feedback paths in high-power converters without external buffering.
How does the dynamic impedance of TL431BQDBZT affect power supply stability?
With a typical dynamic impedance of 0.2 Ω, TL431BQDBZT minimizes output voltage perturbation during rapid load changes-critical for maintaining loop stability in switching regulators. This low impedance reduces phase shift in the feedback path and improves transient response, especially when paired with optocouplers having nonlinear CTR, as documented in TI's Stability Boundary Conditions (Figures 6-18 and 6-19).
TL431BQDBZT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- 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-23-3
TL431BQDBZT FAQ
1.How can I place an order for TL431BQDBZT through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BQDBZT 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 TL431BQDBZT reliable?
The price and inventory of TL431BQDBZT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BQDBZT is usually 5 days.
3.What payment methods are accepted for TL431BQDBZT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BQDBZT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BQDBZT?
TL431BQDBZT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BQDBZT 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 TL431BQDBZT?
For technical support, including TL431BQDBZT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BQDBZT requirements.
6.How does Aetrix verify that TL431BQDBZT is sourced from the original manufacturer or authorized distributors?
All TL431BQDBZT 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 TL431BQDBZT meets industry standards.
7.What is the process for return or replacement of TL431BQDBZT?
All TL431BQDBZT units undergo pre-shipment inspection (PSI). If there is an issue with TL431BQDBZT, 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 TL431BQDBZT part is unused and in its original packaging.
Return procedure for TL431BQDBZT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BQDBZT 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
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
