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Texas Instruments TL431LIAQDBZR
- Part No.:
- TL431LIAQDBZR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431LIAQDBZR.pdf
- Description:
- IC VREF SHUNT ADJ 1% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:14,208
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Product details
Overview
TL431LIAQDBZR from Texas Instruments is a three-terminal adjustable shunt regulator optimized for automotive-grade precision voltage referencing, featuring 1% initial reference voltage tolerance at 25°C, 2.495 V nominal Vref, operation from −40°C to +125°C, 0.3 Ω typical dynamic impedance, and sink-current capability up to 15 mA - used in secondary-side regulation of flyback SMPS and as a Zener diode replacement in onboard power control circuits.
For engineers reviewing the TL431LIAQDBZR datasheet, TL431LIAQDBZR pinout, TL431LIAQDBZR application, or TL431LIAQDBZR equivalent, key selection considerations include its Q-temp automotive qualification, low 0.4 µA max reference input current, 10 mV max Vref drift over −40°C to +125°C, and SOT-23 (DBZ) package compatibility with legacy TL431 designs requiring enhanced thermal stability and leakage performance.
Technical Context
The TL431LIAQDBZR implements an internal bandgap reference and high-gain op-amp driving a Darlington output stage, enabling precise shunt regulation via external resistive feedback between cathode and reference pins. Its closed-loop behavior delivers stable voltage setpoints from 2.495 V to 36 V with minimal dependence on cathode current variation.
It operates in two primary functional modes: open-loop comparator mode (with integrated 2.495 V threshold) and closed-loop shunt regulator mode. In both, the device requires ≥1 mA cathode current (IKA) to maintain linear operation and specified gain; below this, response slows and regulation degrades.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Vref (25°C) | 2.495 V nominal; ±1% (A grade) tolerance ensures ±25 mV absolute accuracy at room temperature for reference-critical biasing. |
| Temp Range | −40°C to +125°C (Q-temp); validated for automotive under-hood and industrial control environments without derating. |
| VKA Range | 2.495 V to 36 V; supports wide-output adjustable regulation using only two external resistors - no additional ICs required. |
| IKA Max | 15 mA continuous cathode sink current; sufficient to drive optocoupler LEDs in isolated feedback loops or bias small loads directly. |
| IREF Max | 0.4 µA at 25°C; ultra-low reference pin current minimizes resistor-divider error and enables high-impedance sensing networks. |
| ZKA Typ | 0.3 Ω dynamic impedance; maintains tight output voltage regulation under load transients and line variations in SMPS applications. |
| VI(dev) | 10 mV max over full temperature range; translates to ~0.0083 mV/°C average tempco - critical for battery monitoring and sensor reference stability. |
| Imin | 1 mA minimum cathode current for regulation; defines lowest usable operating point before gain collapse and regulation loss. |
Pinout & Package
TL431LIAQDBZR is housed in a 3-pin SOT-23 (DBZ) package measuring 2.90 mm × 1.30 mm, with gull-wing leads suitable for automated surface-mount assembly and reflow soldering per JEDEC J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current output / voltage sense node | Sinks regulated current to ANODE; voltage at this pin is the programmable output (VKA), set by REF–ANODE divider network. |
| REF (Pin 2) | Reference input / feedback threshold | Compares external voltage to internal 2.495 V bandgap; must be biased with ≥0.4 µA to enable regulation - not floating. |
| ANODE (Pin 3) | Common return / ground reference | Acts as circuit common; all voltages referenced to this pin; connects to system ground or negative rail in floating configurations. |
Key Features
| Feature | Design Value |
|---|---|
| Automotive Q-temp rating | Qualified per AEC-Q100 Grade 1; guaranteed operation from −40°C to +125°C ambient - suitable for engine control and ADAS power rails. |
| Low IREF & II(dev) | 0.4 µA max IREF and 0.3 µA max deviation over temperature reduce divider loading error and improve long-term reference stability. |
| Sharp turn-on characteristic | High open-loop gain and Darlington output deliver fast, clean switching in comparator mode - ideal for overvoltage detection and fault signaling. |
| Internal compensation | Stable without external capacitor; eliminates need for output bypass in most shunt regulator configurations - reduces BOM count and layout area. |
| Pin-to-pin alternative to TL431 | DBZ package matches industry-standard TL431 footprint; allows drop-in upgrade to improved accuracy, lower drift, and tighter IREF specs. |
Applications
| Secondary-Side Flyback Regulation | Zener Diode Replacement |
|---|---|
Use Scenario: Isolated DC–DC converter where TL431LIAQDBZR senses output voltage via optocoupler feedback to primary-side controller. IC Role / Device Role / Timing Role: Precision shunt regulator providing accurate voltage reference and error amplification function in closed-loop feedback path. Use Value: Enables ±1% output regulation across line/load/temperature with no secondary-side LDO - reduces cost and improves efficiency vs. discrete Zener+transistor solutions. | Use Scenario: Onboard 3.3 V or 5 V rail stabilization in automotive body control modules where space and thermal margin are constrained. IC Role / Device Role / Timing Role: Adjustable shunt reference replacing fixed-voltage Zener diodes with superior initial accuracy and temperature stability. Use Value: Eliminates need for multiple Zener part numbers; single TL431LIAQDBZR supports 2.495–36 V outputs with <10 mV total drift over −40°C to +125°C. |
| Voltage Monitoring & Fault Detection | Precision Constant Current Sink |
Use Scenario: Battery pack voltage supervision in EV charging systems, triggering shutdown if cell voltage exceeds safe threshold. IC Role / Device Role / Timing Role: Comparator with integrated 2.495 V reference, comparing scaled battery voltage to trip point without external reference IC. Use Value: Reduces component count and PCB area; 0.4 µA IREF enables high-resistor-divider networks for low-power monitoring (<10 µA quiescent). | Use Scenario: LED driver for automotive interior lighting, delivering stable 100 mA current independent of forward voltage variation. IC Role / Device Role / Timing Role: Error amplifier controlling external pass transistor to maintain constant current through sense resistor RS. Use Value: Achieves ±1% current accuracy using only TL431LIAQDBZR + 0.1% RS; eliminates need for dedicated current-sense amplifier or DAC-based control. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBZR | Commercial-grade (0°C to 70°C), 2% Vref tolerance, higher 1.5 µA IREF, 50 mV VI(dev) max | Limited to non-automotive, non-industrial ambient environments; less stable over temperature | Select when cost sensitivity outweighs thermal performance and automotive qualification requirements. |
| TLVH431AQDBVR | Lower 1.24 V reference, 0.5% tolerance, 100 µA IREF, Q-temp rated, SOT-23-5 package | Requires different pinout and external components; suited for sub-2.5 V references where TL431LIAQDBZR cannot operate | Choose only when system requires <2.495 V reference voltage and can accommodate 5-pin layout and higher IREF loading. |
Compared with TL431CDBZR, TL431LIAQDBZR offers 3× tighter Vref tolerance, 4× lower IREF, and 5× better temperature drift - making it essential for automotive feedback loops. Versus TLVH431AQDBVR, it provides higher output voltage range and lower dynamic impedance but lacks sub-2.5 V capability.
Availability
TL431LIAQDBZR is available at Aetrix Electronics and suitable for automotive power management, industrial SMPS design, and precision analog monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TL431LIAQDBZR 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.
The TL431LIAQDBZR belongs to TI's precision shunt regulator product line, engineered specifically for high-accuracy, temperature-stable voltage referencing in safety-critical automotive and industrial power systems.
FAQ
What is the maximum cathode voltage (VKA) rating for TL431LIAQDBZR?
The absolute maximum cathode voltage for TL431LIAQDBZR is 37 V, but the recommended operating range is Vref to 36 V. Exceeding 36 V risks violating recommended conditions and may accelerate parametric drift or reduce reliability. The 37 V rating is a stress limit - not intended for continuous operation - and applies only with proper thermal management and within the −40°C to +125°C junction temperature envelope. Always verify VKA against actual application headroom in TL431LIAQDBZR designs.
Does TL431LIAQDBZR require an output capacitor for stability?
No, TL431LIAQDBZR is internally compensated and remains stable without an output capacitor between cathode and anode under standard shunt regulator configurations. This eliminates capacitor-related failure modes and simplifies layout. However, if an output capacitor is added - for example, to filter ripple or improve transient response - its value must be selected using TI's stability boundary charts (Figure 12 in SLVSDQ6A) to avoid oscillation, especially with CL > 10 nF or under varying load conditions. TL431LIAQDBZR's stability is inherently robust but not immune to improper capacitive loading.
Can TL431LIAQDBZR be used as a standalone comparator?
Yes, TL431LIAQDBZR functions as a comparator with integrated 2.495 V reference when operated open-loop: apply voltage to REF, supply ≥1 mA cathode current (IKA), and monitor CATHODE as open-collector output. Its high gain ensures fast response, but timing depends on IKA - e.g., 5 mA yields faster switching than 1 mA. Output low is ~2 V (not rail-to-rail), so level-shifting may be needed for 3.3 V or 1.8 V logic. TL431LIAQDBZR's comparator use avoids external reference ICs and reduces component count in overvoltage/undervoltage detection circuits.
What is the minimum cathode current required for regulation in TL431LIAQDBZR?
The minimum cathode current (Imin) for reliable regulation in TL431LIAQDBZR is 1 mA - specified as maximum value, meaning regulation is guaranteed down to 1 mA across temperature and process variation. Operating below this risks gain reduction, slower response, and loss of regulation accuracy. Designers should target ≥2 mA for margin, especially in automotive applications where cold-start or low-load conditions may reduce available IKA. TL431LIAQDBZR's 1 mA Imin enables efficient operation in low-power feedback paths such as optocoupler-driven SMPS controllers.
How does the TL431LIAQDBZR pinout differ from TL432LI in the same DBZ package?
In the DBZ (SOT-23) package, TL431LIAQDBZR has CATHODE on Pin 1, REF on Pin 2, and ANODE on Pin 3; TL432LI swaps REF and CATHODE - placing REF on Pin 1 and CATHODE on Pin 2. This pinout difference means TL431LIAQDBZR is not mechanically or electrically interchangeable with TL432LI without PCB redesign. Both share identical electrical specs and Q-temp rating, but TL431LIAQDBZR maintains legacy TL431 pin compatibility, while TL432LI offers alternate routing flexibility. Always verify pin mapping before board layout or replacement in TL431LIAQDBZR designs.
TL431LIAQDBZR 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:
- 15 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
TL431LIAQDBZR FAQ
1.How can I place an order for TL431LIAQDBZR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431LIAQDBZR 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 TL431LIAQDBZR reliable?
The price and inventory of TL431LIAQDBZR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431LIAQDBZR is usually 5 days.
3.What payment methods are accepted for TL431LIAQDBZR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431LIAQDBZR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431LIAQDBZR?
TL431LIAQDBZR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431LIAQDBZR 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 TL431LIAQDBZR?
For technical support, including TL431LIAQDBZR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431LIAQDBZR requirements.
6.How does Aetrix verify that TL431LIAQDBZR is sourced from the original manufacturer or authorized distributors?
All TL431LIAQDBZR 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 TL431LIAQDBZR meets industry standards.
7.What is the process for return or replacement of TL431LIAQDBZR?
All TL431LIAQDBZR units undergo pre-shipment inspection (PSI). If there is an issue with TL431LIAQDBZR, 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 TL431LIAQDBZR part is unused and in its original packaging.
Return procedure for TL431LIAQDBZR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431LIAQDBZR Tags
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