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Texas Instruments TL431BQDBZRQ1
- Part No.:
- TL431BQDBZRQ1
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431BQDBZRQ1.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:19,120
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Product details
Overview
TL431BQDBZRQ1 from Texas Instruments is an automotive-grade adjustable precision shunt regulator in SOT-23 (DBZ) package, functioning as a 2.495 V ±0.5% reference with 0.2 Ω dynamic impedance, 1 mA–100 mA sink-current capability, and –40°C to 125°C operation-used for secondary-side regulation in isolated flyback converters and voltage monitoring in EV battery management systems.
For engineers reviewing the TL431BQDBZRQ1 datasheet, TL431BQDBZRQ1 pinout, TL431BQDBZRQ1 application, or TL431BQDBZRQ1 equivalent, key selection criteria include its AEC-Q100 Grade 1 qualification, 14 mV max reference voltage deviation over temperature, low 2–4 µA reference current, 36 V cathode voltage rating, and compatibility with Zener-replacement and error-amplifier topologies requiring stable 2.5 V reference accuracy.
Technical Context
The TL431BQDBZRQ1 integrates a precision bandgap reference and high-gain NPN-based error amplifier in a three-terminal shunt topology. Its internal Darlington output stage enables 100 mA sink capability while maintaining 0.2 Ω typical dynamic impedance below 1 kHz.
It operates in closed-loop regulation (e.g., feedback from cathode to REF) for adjustable voltage control from 2.495 V to 36 V, or in open-loop comparator mode with integrated reference for undervoltage/overvoltage detection-requiring ≥1 mA cathode current and ≤10 mA reference input current to remain in linear region.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VREF @ 25°C | 2.495 V ±0.5% - sets precise regulation threshold; enables <±12.5 mV absolute error at room temperature. |
| VI(DEV) | 14 mV max over –40°C to 125°C - ensures <±7 mV worst-case drift in automotive thermal environments. |
| IKA Range | 1 mA to 100 mA - supports wide load range in shunt regulation; minimum 1 mA required for stable regulation. |
| |ZKA| | 0.2 Ω typical at 1–100 mA, ≤1 kHz - provides low-impedance reference node critical for feedback stability in SMPS. |
| VKA Max | 36 V - allows direct use in 24 V automotive systems and 36 V industrial rails without external clamping. |
| IREF | 2–4 µA - minimizes resistor-divider loading error; enables high-impedance sensing in battery monitor circuits. |
| Package | SOT-23 (DBZ), 2.92 mm × 1.30 mm - surface-mount compatible with automated assembly; thermal resistance RθJA = 334.7°C/W. |
Pinout & Package
SOT-23 (DBZ) 3-pin plastic package with gull-wing leads; body size 2.92 mm × 1.30 mm; anode connected to die substrate and PCB thermal pad (if used).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: CATHODE | Current sink output / voltage sense node | Accepts up to 100 mA sink current; connects to SMPS transformer secondary or voltage divider output; voltage referenced to ANODE. |
| 2: REF | Reference input / error amplifier inverting input | Compares external voltage to internal 2.495 V reference; requires 2–4 µA bias current; must not float-tied to resistive divider midpoint. |
| 3: ANODE | Common return / ground reference | Internal substrate connection; serves as circuit ground reference for both REF and CATHODE; must be connected to system ground or lowest potential node. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualified | Validated for –40°C to 125°C ambient operation-meets automotive ECU and ADAS power rail requirements. |
| 0.5% initial VREF tolerance (B grade) | Reduces calibration overhead in safety-critical voltage monitors; eliminates need for post-production trimming. |
| Low 14 mV VI(DEV) over full temp range | Enables ±0.56% max reference error across automotive temperature swing-critical for battery cell voltage accuracy. |
| 0.2 Ω dynamic impedance | Minimizes output voltage perturbation under transient load steps-supports tight regulation in 500 kHz+ flyback designs. |
| Zener diode replacement capability | Replaces discrete Zeners with superior stability, lower noise, and programmable output-reducing BOM count in multi-rail supplies. |
Applications
| Onboard DC-DC Regulation | Secondary-Side Flyback Control |
|---|---|
Use Scenario: Regulating 5 V or 3.3 V output from 12 V or 24 V automotive supply using discrete LDO or buck controller with external feedback. IC Role / Device Role / Timing Role: Adjustable shunt reference providing precise 2.495 V threshold for error amplifier feedback loop. Use Value: Enables ±1% output accuracy over temperature without trimming; replaces 5% Zener diodes with 10× better drift performance. |
Use Scenario: Isolated feedback path in automotive AC/DC or DC/DC flyback converters where primary-side controller lacks optocoupler interface. IC Role / Device Role / Timing Role: Shunt regulator driving optocoupler LED on secondary side to close regulation loop across isolation barrier. Use Value: Provides stable 2.495 V reference for accurate output voltage replication; supports 100 mA sink to drive high-CTR optocouplers directly. |
| Battery Voltage Monitoring | Overvoltage/Undervoltage Detection |
Use Scenario: Monitoring individual cell voltages in 12S Li-ion traction battery packs with microcontroller ADC input protection. IC Role / Device Role / Timing Role: Precision voltage clamp limiting ADC input to safe range while preserving resolution near 2.5 V threshold. Use Value: Delivers 0.5% reference accuracy at 125°C-ensures cell voltage measurement remains within ±5 mV of true value during thermal stress. |
Use Scenario: Detecting 12 V rail collapse (<10.5 V) or surge (>15 V) in engine control modules to trigger fault logging or shutdown. IC Role / Device Role / Timing Role: Comparator with integrated reference comparing sensed rail voltage against 2.495 V via resistor divider. Use Value: Eliminates external reference IC; achieves <10 µs response time with 1 mA cathode current-faster than discrete op-amp + ref solutions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431LIQDBZRQ1 | Pin-to-pin compatible; lower 8 mV VI(DEV), 1.5 µA IREF, improved stability margin with capacitive loads. | Better suited for high-accuracy battery monitors and low-power always-on detection circuits. | Select when tighter reference drift or reduced divider current is required; same PCB layout. |
| TL431BIDBZR | Industrial-grade (non-automotive); identical electrical specs but no AEC-Q100 qualification or extended temp screening. | Applicable only in non-safety-critical consumer or industrial power supplies. | Choose for cost-sensitive non-automotive designs where Grade 1 qualification is unnecessary. |
Compared with TL431BQDBZRQ1, TL431LIQDBZRQ1 offers measurable improvement in temperature drift and reference current for high-accuracy systems, while TL431BIDBZR reduces cost in non-automotive applications-but neither provides the AEC-Q100 Grade 1 assurance required for functional safety compliance.
Availability
TL431BQDBZRQ1 is available at Aetrix Electronics and suitable for automotive power conversion, battery management, and voltage supervision applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL431BQDBZRQ1 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 designing analog ICs, embedded processors, and system solutions for automotive, industrial, and communications markets.
The TL43x-Q1 product line delivers AEC-Q100 qualified precision references for safety-critical automotive subsystems-including powertrain, chassis, and battery management-where stable 2.5 V reference accuracy over temperature is mandatory.
FAQ
What is the maximum cathode voltage rating for TL431BQDBZRQ1?
The TL431BQDBZRQ1 has a maximum cathode voltage (VKA) rating of 36 V, specified under Absolute Maximum Ratings. This allows direct use in 24 V automotive systems and 36 V industrial rails without external clamping components. Operation above 36 V risks permanent damage, and design margins should maintain VKA ≤33 V for reliability per TI's recommended operating conditions.
Does TL431BQDBZRQ1 require an output capacitor for stability?
No, TL431BQDBZRQ1 is internally compensated and stable without an output capacitor between cathode and anode-unlike many linear regulators. However, if a capacitor is added for noise filtering or transient suppression, its value must be selected using TI's stability boundary charts (Figures 12–13) to avoid oscillation, especially with >100 pF loads at high cathode currents.
What is the minimum cathode current needed for regulation in TL431BQDBZRQ1?
The TL431BQDBZRQ1 requires a minimum cathode current (IMIN) of 0.7 mA for reliable regulation, per Electrical Characteristics for TL43xB-Q1. Below this level, gain drops significantly-causing slow response, poor line/load regulation, and potential dropout. Designs must ensure ≥1 mA cathode current under all operating conditions, including light-load and cold-start scenarios.
How does the REF pin function in TL431BQDBZRQ1?
The REF pin of TL431BQDBZRQ1 serves as the inverting input of an internal error amplifier, comparing external voltage to the 2.495 V bandgap reference. It draws 2–4 µA (IREF) and must be driven by a low-impedance source-typically a resistor divider from cathode. Floating REF causes malfunction; excessive series resistance introduces voltage drop that degrades regulation accuracy.
Is TL431BQDBZRQ1 pin-compatible with TL432-Q1?
No-TL431BQDBZRQ1 and TL432-Q1 share the same DBZ package but have reversed pinouts: TL431BQDBZRQ1 uses Pin 1=CATHODE, Pin 2=REF, Pin 3=ANODE, whereas TL432-Q1 uses Pin 1=REF, Pin 2=CATHODE, Pin 3=ANODE. Interchanging them without PCB revision causes immediate functional failure due to incorrect reference and current path connections.
TL431BQDBZRQ1 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:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
TL431BQDBZRQ1 FAQ
1.How can I place an order for TL431BQDBZRQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BQDBZRQ1 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 TL431BQDBZRQ1 reliable?
The price and inventory of TL431BQDBZRQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BQDBZRQ1 is usually 5 days.
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TL431BQDBZRQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BQDBZRQ1 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 TL431BQDBZRQ1?
For technical support, including TL431BQDBZRQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BQDBZRQ1 requirements.
6.How does Aetrix verify that TL431BQDBZRQ1 is sourced from the original manufacturer or authorized distributors?
All TL431BQDBZRQ1 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 TL431BQDBZRQ1 meets industry standards.
7.What is the process for return or replacement of TL431BQDBZRQ1?
All TL431BQDBZRQ1 units undergo pre-shipment inspection (PSI). If there is an issue with TL431BQDBZRQ1, 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 TL431BQDBZRQ1 part is unused and in its original packaging.
Return procedure for TL431BQDBZRQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BQDBZRQ1 Tags
-
TL431AIDBZR
Texas Instruments
-
TL431BQDBZR
Texas Instruments
-
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
-
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
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AZ431LANTR-G1
Diodes Incorporated
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