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STMicroelectronics TL431IL3T
- Part No.:
- TL431IL3T
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TL431IL3T.pdf
- Description:
- IC VREF SHUNT ADJ 2.21% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,780
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Product details
Overview
TL431IL3T from STMicroelectronics is an AEC-Q100 qualified automotive-grade adjustable shunt voltage reference in SOT23-3 package, delivering 2.5–36 V output via two external resistors, 1–100 mA sink current capability, 0.22 Ω typical dynamic impedance, and ±2% initial voltage accuracy over –40 °C to +125 °C operating range-used in feedback loops of isolated DC-DC converters and battery management systems.
For engineers reviewing the TL431IL3T datasheet, TL431IL3T pinout, TL431IL3T application, or TL431IL3T equivalent, key selection criteria include automotive temperature compliance, shunt reference stability under variable load, cathode-anode voltage headroom (up to 36 V), and SOT23-3 footprint compatibility with space-constrained power supply designs.
Technical Context
The TL431IL3T operates as a three-terminal programmable shunt regulator: its REF pin senses a divided fraction of cathode voltage, triggering internal error amplifier and NPN output stage to sink current and clamp VKA at precise VREF × (1 + R1/R2). It requires no external compensation for stable operation with capacitive loads up to 10 µF.
Its architecture supports both fixed and adjustable configurations-VREF is internally trimmed to 2.495 V (typ.) with ±2% tolerance, and the device maintains regulation down to 0.5 mA minimum cathode current while exhibiting only 7 mV max ΔVREF across –40 °C to +125 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V (typ.), ±2% initial accuracy-sets output voltage precision in feedback networks. |
| Output Voltage Range | 2.5 V to 36 V-programmable via external resistor divider without requiring additional ICs. |
| Sink Current Range | 1 mA to 100 mA-supports direct regulation of low-power supplies and optocoupler biasing. |
| Dynamic Impedance | 0.22 Ω (typ.)-ensures minimal output voltage deviation under fast load transients. |
| Temp. Range | –40 °C to +125 °C-qualified per AEC-Q100 Grade 1 for under-hood automotive applications. |
| Voltage Deviation | ±7 mV over full temp. range-guarantees stable reference performance in thermal cycling environments. |
| Min. Cathode Current | 0.5 mA-enables reliable regulation even in ultra-low-power standby modes. |
Pinout & Package
SOT23-3 plastic surface-mount package (3-pin, 1.3 mm height, 2.9 mm × 1.3 mm footprint) with gull-wing leads, RoHS-compliant and ECOPACK® certified.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Cathode) | Current sink output | Connects to regulated rail; sinks current to maintain set voltage at REF node. |
| Pin 2 (Anode) | Return path | Common ground reference for internal amplifier; ties to system GND or negative rail. |
| Pin 3 (REF) | Feedback input | High-impedance (≤4 µA) sense node; connects to resistor divider midpoint for voltage programming. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualification | Grade 1 (–40 °C to +125 °C) ensures reliability in automotive powertrain and body electronics. |
| Adjustable output | 2.5–36 V range enables reuse across multiple supply rails without redesigning feedback network. |
| Low dynamic impedance | 0.22 Ω (typ.) minimizes output ripple and improves transient response in closed-loop regulators. |
| Wide cathode current range | 1–100 mA operation supports both low-quiescent and high-current regulation scenarios. |
| Stable with capacitive loads | No external compensation required for ≤10 µF output capacitance-reduces BOM count and layout complexity. |
Applications
| Isolated Flyback Converter Feedback | Automotive Battery Monitor |
|---|---|
|
Use Scenario: Provides precise voltage reference for optocoupler-based feedback in 12 V/48 V isolated DC-DC converters. IC Role / Device Role / Timing Role: Shunt reference sets secondary-side output voltage threshold; regulates primary-side controller via photocurrent modulation. Use Value: Enables ±2% output regulation across temperature and line variations without secondary-side LDO or DAC. |
Use Scenario: Monitors cell stack voltage in 12 V lead-acid or 48 V mild-hybrid battery systems. IC Role / Device Role / Timing Role: Programmable reference feeds comparator or ADC input to detect overvoltage/undervoltage thresholds. Use Value: Delivers stable 2.5 V reference despite engine cranking dips and alternator ripple-no external trimming needed. |
| Industrial SMPS Voltage Trim | LED Driver Current Reference |
|
Use Scenario: Fine-tunes output voltage of programmable industrial power supplies using digital potentiometer interface. IC Role / Device Role / Timing Role: Adjustable shunt reference replaces fixed Zener; REF pin driven by DAC or microcontroller GPIO. Use Value: Achieves 0.1% resolution voltage adjustment with <10 µA REF pin current-minimizes DAC loading error. |
Use Scenario: Sets constant current for high-brightness LED strings in automotive lighting modules. IC Role / Device Role / Timing Role: Configured as current source via REF-to-anode resistor; cathode drives LED anode through series FET. Use Value: Maintains ±2% current accuracy over –40 °C to +125 °C-critical for consistent lumen output and thermal derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACL3T | ±1% initial voltage accuracy (vs. ±2%); otherwise identical pinout, specs, and temp. range. | Better precision required for high-accuracy feedback or sensor biasing where 1% tolerance is mandated. | Select when tighter initial VREF tolerance is needed without changing layout or thermal design. |
| TL432IL3T | Includes internal 2.5 V reference (non-adjustable mode); same SOT23-3 package and automotive rating. | Used where fixed 2.5 V reference suffices-eliminates external resistor divider and reduces component count. | Choose for simplified designs needing only 2.5 V reference, avoiding resistor matching and layout sensitivity. |
Compared with TL431IL3T, TL431ACL3T offers higher initial accuracy at same cost and footprint, while TL432IL3T trades adjustability for reduced external components-both retain AEC-Q100 qualification and thermal performance.
Availability
TL431IL3T is available at Aetrix Electronics and suitable for automotive power conversion, industrial SMPS, and battery monitoring systems requiring stable component supply with guaranteed AEC-Q100 compliance and long-term production continuity.
Supply support for TL431IL3T 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and automotive-grade ICs for industrial, automotive, and consumer markets.
The TL431 family belongs to ST's precision analog portfolio, engineered specifically for high-reliability voltage reference and feedback applications in harsh-environment power systems.
FAQ
What is the maximum cathode-to-anode voltage the TL431IL3T can withstand?
The absolute maximum cathode-to-anode voltage (VKA) is 37 V. Operation up to 36 V is specified in electrical characteristics, with derating recommended above 30 V to manage power dissipation and ensure long-term reliability in automotive thermal environments.
Can TL431IL3T replace a Zener diode in existing designs?
Yes-TL431IL3T functions as a superior 2.5 V Zener replacement with adjustable output, lower dynamic impedance (0.22 Ω vs. typical 10–100 Ω for Zeners), and tighter voltage tolerance. Requires only two external resistors for adjustment and maintains regulation down to 0.5 mA cathode current.
Does TL431IL3T require external compensation for stability?
No external compensation is required. The device is internally compensated and remains stable with capacitive loads up to 10 µF, making it suitable for direct use with bulk output capacitors in switching power supplies without added RC networks or phase-margin tuning.
How does the REF pin input current affect accuracy in precision applications?
REF pin current is ≤4 µA (max) and exhibits ≤2.5 µA deviation over temperature. In high-precision resistor dividers, this current introduces <0.1% gain error if R1+R2 ≤ 10 kΩ; for sub-0.05% accuracy, use R1+R2 ≤ 2 kΩ or add a buffer op-amp to isolate the divider.
TL431IL3T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- 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:
- ±2.21%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
TL431IL3T FAQ
1.How can I place an order for TL431IL3T through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431IL3T 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 TL431IL3T reliable?
The price and inventory of TL431IL3T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431IL3T is usually 5 days.
3.What payment methods are accepted for TL431IL3T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431IL3T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431IL3T?
TL431IL3T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431IL3T 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 TL431IL3T?
For technical support, including TL431IL3T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431IL3T requirements.
6.How does Aetrix verify that TL431IL3T is sourced from the original manufacturer or authorized distributors?
All TL431IL3T 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 TL431IL3T meets industry standards.
7.What is the process for return or replacement of TL431IL3T?
All TL431IL3T units undergo pre-shipment inspection (PSI). If there is an issue with TL431IL3T, 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 TL431IL3T part is unused and in its original packaging.
Return procedure for TL431IL3T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431IL3T Tags
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