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Texas Instruments ATL431LIAQDBZR
- Part No.:
- ATL431LIAQDBZR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
ATL431LIAQDBZR.pdf
- Description:
- IC VREF SHUNT ADJ 1% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,261
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Product details
Overview
ATL431LIAQDBZR from Texas Instruments is a precision programmable shunt voltage regulator with 1% initial reference voltage tolerance at 25°C, adjustable output voltage from 2.5 V to 36 V, 0.3 Ω typical dynamic impedance, −40°C to +125°C automotive-grade operating temperature range, and 0.4 µA maximum reference input current - used for secondary-side regulation in isolated flyback converters.
For engineers reviewing the ATL431LIAQDBZR datasheet, ATL431LIAQDBZR pinout, ATL431LIAQDBZR application, or ATL431LIAQDBZR equivalent, this page delivers verified electrical specs, thermal performance data, SOT-23-3 pin mapping, real-world use cases in voltage monitoring and Zener replacement, and two validated alternative parts with documented functional differences.
Technical Context
The ATL431LIAQDBZR implements a three-terminal shunt topology with an internal 2.5-V bandgap reference and high-gain transconductance amplifier driving a Darlington output stage. Its sharp turn-on characteristic and low 0.3-Ω dynamic impedance enable stable regulation under varying load and line conditions without external compensation.
It operates in closed-loop mode when feedback is applied between cathode and reference pins to regulate voltage or current, and in open-loop comparator mode when the reference pin senses an external signal - supporting both precision referencing and over/under-voltage detection functions within a single device.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VREF Tolerance | 1% at 25°C (A grade) - ensures ±25 mV absolute error in reference setting for tight voltage margin designs |
| Adjustable Range | 2.5 V to 36 V - supports wide-input industrial and automotive power supplies via two-resistor divider |
| Temp Drift (Q Grade) | 27 mV max over −40°C to +125°C - guarantees <0.08%/°C drift for high-stability regulation across full automotive temp range |
| IKA Max | 15 mA - enables direct sinking of error amplifier currents in SMPS feedback loops without external buffer |
| Imin | 80 µA max - allows ultra-low-power operation in battery-backed monitoring circuits |
| IREF | 0.4 µA max - minimizes resistor-divider loading error and improves accuracy in high-impedance feedback networks |
| ZKA | 0.3 Ω typical - provides low-output-impedance regulation critical for fast transient response in switching converters |
Pinout & Package
ATL431LIAQDBZR is housed in a 3-pin SOT-23 (DBZ) package measuring 2.90 mm × 1.30 mm, optimized for space-constrained PCB layouts and compatible with standard pick-and-place equipment.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current input/output node | Connects to regulated output node; sinks current to maintain set voltage - must be biased above VREF by ≥2.5 V for regulation |
| REF (Pin 2) | Reference input sensing node | High-impedance input (≤0.4 µA) that compares external voltage to internal 2.5-V reference - requires stable bias path to avoid oscillation |
| ANODE (Pin 3) | Common return / ground reference | Low-impedance connection point for cathode current return; must be tied to system ground or lowest potential node in feedback loop |
Key Features
| Feature | Design Value |
|---|---|
| Automotive Q-temp qualification | Rated for −40°C to +125°C operation - qualified per AEC-Q100 for under-hood and infotainment power management |
| Low IREF and Imin | 0.4 µA max IREF, 80 µA max Imin - reduces power loss in high-resistance feedback dividers and extends battery life in always-on monitors |
| Stable without output capacitor | Internally compensated - eliminates need for external cathode-to-anode capacitor in most applications, simplifying layout and BOM |
| Sharp turn-on characteristic | Fast transition from off-state to regulation - enables reliable Zener diode replacement in precision clamping and overvoltage protection circuits |
| PIN-to-PIN compatibility with TL431LI | Direct drop-in replacement for legacy TL431LI in SOT-23-3 footprint - preserves existing PCB design while improving power efficiency and thermal stability |
Applications
| Secondary-Side Regulation | Zener Diode Replacement |
|---|---|
Use Scenario: Isolated flyback converter where primary-side controller lacks direct output voltage sensing. IC Role / Device Role / Timing Role: Shunt regulator providing optocoupler feedback signal proportional to output voltage deviation. Use Value: Enables accurate ±1% output regulation across line/load/temperature using only two external resistors and optocoupler - no secondary-side controller IC required. | Use Scenario: Overvoltage clamp protecting downstream analog circuitry from supply rail surges. IC Role / Device Role / Timing Role: Precision voltage clamp replacing discrete Zener diodes with tighter tolerance and lower temperature drift. Use Value: Delivers 1% initial accuracy and 27 mV max drift over −40°C to +125°C - outperforms standard 5% Zeners in automotive and industrial environments. |
| Voltage Monitoring | Precision Constant Current Sink |
Use Scenario: Real-time monitoring of 12-V or 24-V battery voltage in telematics or ADAS modules. IC Role / Device Role / Timing Role: Comparator with integrated reference detecting undervoltage (UVLO) or overvoltage (OVLO) thresholds. Use Value: Uses internal 2.5-V reference and external resistor divider to set precise trip points - eliminates external reference IC and reduces component count. | Use Scenario: LED driver or sensor biasing requiring stable current independent of supply variation. IC Role / Device Role / Timing Role: Adjustable current sink configured with cathode connected to load and reference tied to sense resistor. Use Value: Achieves ≤1% current accuracy over temperature using only one external resistor - replaces opamp-based current sources in cost-sensitive designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431LIQDBZR | Same pinout and function but higher 100-µA min cathode current and 2% VREF tolerance (A grade) | Less suitable for ultra-low-power systems; reduced accuracy in precision feedback loops | Select when legacy compatibility is mandatory and power budget allows higher Imin |
| ATL432LIAQDBZR | Identical electrical specs but reversed REF/CATHODE pinout in DBZ package (Pin 1 = REF, Pin 2 = CATHODE) | Requires PCB layout revision; not drop-in - incompatible with ATL431LIAQDBZR footprint | Select only if redesigning board and needing alternate pin assignment for routing optimization |
Compared with TL431LIQDBZR, ATL431LIAQDBZR offers 20× lower minimum cathode current and tighter 1% reference tolerance - enabling higher efficiency and accuracy in modern flyback and monitoring designs. Compared with ATL432LIAQDBZR, it retains the industry-standard pinout, avoiding layout changes while delivering identical performance.
Availability
ATL431LIAQDBZR is available at Aetrix Electronics and suitable for automotive power management, industrial SMPS feedback, and battery voltage monitoring requiring stable component supply across extended temperature ranges.
Supply support for ATL431LIAQDBZR 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 specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and automotive electronics.
The ATL431LIAQDBZR belongs to TI's high-precision shunt regulator product line, designed specifically for automotive-grade secondary-side regulation, voltage supervision, and Zener replacement in safety-critical and thermally demanding applications.
FAQ
What is the maximum cathode voltage rating for ATL431LIAQDBZR?
The ATL431LIAQDBZR has an absolute maximum cathode-to-anode voltage (VKA) rating of 37 V, with recommended operating range from VREF (2.5 V) up to 36 V. Exceeding 37 V risks permanent damage. This rating enables safe use in 24-V automotive systems and 36-V industrial rails while maintaining margin for transients.
Does ATL431LIAQDBZR require an external capacitor for stability?
No, ATL431LIAQDBZR is internally compensated and stable without an external cathode-to-anode capacitor in most configurations. However, when driving capacitive loads >100 pF or operating near instability boundaries (e.g., low IKA or high CL), consult Figure 13 in the datasheet to select a stabilizing capacitor - the device itself does not mandate one for basic regulation.
What is the purpose of the ANODE pin on ATL431LIAQDBZR?
The ANODE pin (Pin 3) serves as the common return path for cathode current and the reference ground for the internal 2.5-V bandgap. It must be connected directly to system ground or the lowest-potential node in the feedback network. Floating or high-impedance ANODE connections cause regulation failure and unpredictable output behavior in ATL431LIAQDBZR.
How does ATL431LIAQDBZR differ from standard TL431 devices?
ATL431LIAQDBZR improves upon TL431 with 1% VREF tolerance (vs. 2%), 80 µA max Imin (vs. 100 µA), and guaranteed −40°C to +125°C Q-temp operation. It maintains pin-to-pin compatibility with TL431LI in SOT-23-3, allowing direct replacement while delivering lower system power consumption and better thermal stability in ATL431LIAQDBZR-based designs.
Can ATL431LIAQDBZR be used as a comparator?
Yes, ATL431LIAQDBZR operates as a high-gain comparator in open-loop mode: apply voltage to the REF pin and monitor the CATHODE output. When REF voltage exceeds 2.5 V (±1%), the cathode pulls low (~2 V); otherwise, it remains high (near VKA). This enables over/under-voltage detection without external reference - a core capability confirmed in Section 10.4.1 of the ATL431LIAQDBZR datasheet.
ATL431LIAQDBZR 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):
- 2.5V
- 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:
- 100 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
ATL431LIAQDBZR FAQ
1.How can I place an order for ATL431LIAQDBZR through Aetrix?
Please submit a Request for Quotation (RFQ) for ATL431LIAQDBZR 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 ATL431LIAQDBZR reliable?
The price and inventory of ATL431LIAQDBZR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ATL431LIAQDBZR is usually 5 days.
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Once your ATL431LIAQDBZR 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 ATL431LIAQDBZR?
For technical support, including ATL431LIAQDBZR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ATL431LIAQDBZR requirements.
6.How does Aetrix verify that ATL431LIAQDBZR is sourced from the original manufacturer or authorized distributors?
All ATL431LIAQDBZR 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 ATL431LIAQDBZR meets industry standards.
7.What is the process for return or replacement of ATL431LIAQDBZR?
All ATL431LIAQDBZR units undergo pre-shipment inspection (PSI). If there is an issue with ATL431LIAQDBZR, 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 ATL431LIAQDBZR part is unused and in its original packaging.
Return procedure for ATL431LIAQDBZR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ATL431LIAQDBZR Tags
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TL431AIDBZR
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