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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Reference

STMicroelectronics TL431AIL5T

Name: TL431AIL5T
Brand: STMicroelectronics
SKU: TL431AIL5T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TL431AIL5T

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

Package:: SC-74A, SOT-753

Datasheet:: TL431AIL5T.pdf

Description:: IC VREF SHUNT ADJ 1% SOT23-5

Quantity:: RFQ Add To RFQ list

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Inventory:10,074

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Product details

Overview

TL431AIL5T from STMicroelectronics is an AEC-Q100 qualified automotive-grade adjustable shunt voltage reference in SOT23-5 package, delivering 1% initial voltage precision (2.47–2.52 V at 25 °C), −40 °C to +125 °C operating range, 0.22 Ω typical dynamic impedance, and 1–100 mA sink current capability. It serves as the precision feedback element in isolated DC-DC converters, battery management systems, and automotive power supply supervision circuits.

For engineers reviewing the TL431AIL5T datasheet, TL431AIL5T pinout, TL431AIL5T application, or TL431AIL5T equivalent, key selection criteria include its automotive temperature rating, 1% V_REF tolerance, SOT23-5 thermal resistance (67 °C/W junction-to-case), and compatibility with optocoupler-based feedback loops in flyback regulators.

Technical Context

The TL431AIL5T implements a 2.5 V bandgap-referenced error amplifier with internal NPN transistor output stage, configured as a programmable shunt regulator. Its reference input (REF) compares against an external resistor divider to control cathode current flow, enabling precise output voltage setting from 2.5 V to 36 V.

It operates across 1–100 mA cathode current with guaranteed stability into capacitive loads up to 10 µF, and features low temperature drift (±7 mV over −40 °C to +125 °C) and minimal voltage variation versus cathode-anode voltage (−2.7 to −1.4 mV/V).

Key Specifications

Parameter	Value and Actual Design Meaning
V_REF (25 °C)	2.47–2.52 V - 1% initial accuracy enables ±1% output regulation without trimming in automotive power supplies.
Temp. Range	−40 °C to +125 °C - AEC-Q100 qualified for under-hood and body-control module applications.
Dynamic Impedance	0.22 Ω typical - ensures stable regulation under fast load transients in switching power supplies.
Cathode Current	1–100 mA - supports wide-range feedback loop biasing and direct LED driver use.
ΔV_REF/ΔT	±7 mV max - limits output voltage drift to < ±0.3% over full automotive temperature range.
I_REF	≤ 4 µA max - minimizes divider resistor power loss and improves high-side sensing accuracy.
Off-state I_K	≤ 500 nA - enables ultra-low quiescent current in always-on monitoring circuits.

Pinout & Package

SOT23-5 plastic surface-mount package (5-pin, 1.9 mm × 2.8 mm footprint), rated for 67 °C/W junction-to-case thermal resistance and compatible with standard reflow profiles.

Pin/Terminal	Circuit Role	Design Meaning
1 (Cathode)	Current sink output	Connects to regulated rail or optocoupler anode; carries full load-adjusted shunt current.
2 (Anode)	Current return path	Connected to ground or low-side return; completes shunt current loop.
3 (REF)	Precision reference input	High-impedance node (≤4 µA) tied to resistor divider midpoint; sets output voltage via V_OUT = V_REF(1 + R1/R2).
4 (NC)	No connect	Internally unconnected; must be left floating or tied to GND per layout best practices.
5 (NC)	No connect	Internally unconnected; electrically isolated from die; no routing required.

Key Features

Feature	Design Value
AEC-Q100 qualification	Validated for automotive Grade 1 (−40 °C to +125 °C), including HTOL, TC, and ESD testing per specification.
Adjustable output range	2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-voltage references in multi-rail systems.
Low dynamic impedance	0.22 Ω typical - maintains tight regulation during rapid load steps in engine control unit (ECU) power rails.
Stable into capacitive loads	Compatible with ≥10 µF output capacitance - simplifies design of low-noise LDO pre-regulators and battery monitor filters.
Minimal reference current	≤4 µA max - allows use of high-value divider resistors (>1 MΩ), reducing standby power in telematics modules.

Applications

Automotive DC-DC Feedback

Battery Cell Supervision

Use Scenario: Isolated flyback converter in ADAS camera ECU requiring stable 5 V/3.3 V rails under cold-crank (4.5 V input) and load dump (42 V input) conditions.

IC Role / Device Role / Timing Role: Precision shunt reference providing optocoupler feedback signal to primary-side PWM controller.

Use Value: 1% V_REF tolerance and −40 °C to +125 °C operation ensure ±1.5% output regulation across full vehicle lifecycle without recalibration.

Use Scenario: High-side voltage monitoring of 12 V lead-acid battery in start-stop system, detecting undervoltage (<11.5 V) and overvoltage (>14.8 V) events.

IC Role / Device Role / Timing Role: Programmable threshold detector with resistor-programmed trip points, interfacing to microcontroller ADC input.

Use Value: Low 4 µA reference current enables >100 kΩ divider network, minimizing battery drain during sleep mode (≤1 µA total).

Industrial SMPS Trim

Programmable Current Sink

Use Scenario: Field-configurable 24 V industrial PLC power supply where output voltage must be adjusted via DIP switch or firmware-selected resistor network.

IC Role / Device Role / Timing Role: Adjustable shunt reference replacing fixed TL431 variants to support multiple output voltages from single PCB design.

Use Value: 2.5–36 V programmability allows one BOM item to cover 12 V, 24 V, and 48 V output configurations with <0.5% step resolution.

Use Scenario: Constant-current LED driver for automotive interior lighting, requiring 100 mA ±2% sink current across temperature and supply variations.

IC Role / Device Role / Timing Role: Shunt regulator configured as precision current sink using REF-to-anode resistor and cathode load connection.

Use Value: 0.22 Ω dynamic impedance and 1–100 mA operating range enable ±1.2 mA current accuracy over −40 °C to +125 °C.

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	SOT23-3 package, same 1% V_REF, but higher R_thJA (248 °C/W) and no NC pins.	Limited to lower-power applications (<300 mW dissipation); unsuitable for high-current or thermally constrained layouts.	Select when board space is critical and thermal load ≤150 mW; avoid in high-ambient automotive locations.
TL432AIL5T	Identical pinout and specs, but includes internal 2.5 V reference bypass capacitor for improved noise immunity.	Better suited for noisy environments (e.g., motor drive power supplies) where reference node susceptibility matters.	Prefer when EMI/RFI rejection is prioritized over cost; requires no external capacitor unlike TL431 variants.

Compared with TL431ACL3T, TL431AIL5T offers superior thermal performance (67 vs. 248 °C/W) and layout flexibility via NC pins; compared with TL432AIL5T, it lacks integrated bypass capacitance but provides identical regulation accuracy at lower unit cost.

Availability

TL431AIL5T is available at Aetrix Electronics and suitable for automotive power supply feedback, battery voltage monitoring, industrial SMPS trim, and programmable current sink applications requiring stable component supply across extended temperature ranges.

Supply support for TL431AIL5T 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, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

The TL431/TL432 product line delivers AEC-Q100 qualified, precision shunt references optimized for automotive power management, battery monitoring, and industrial feedback control systems demanding high reliability and temperature stability.

FAQ

What is the maximum cathode-anode voltage the TL431AIL5T can withstand?

The absolute maximum cathode-to-anode voltage (V_KA) is 37 V. Operation above this value risks permanent damage. In normal regulation, V_KA equals the programmed output voltage (2.5–36 V), so designs must ensure transient overvoltages (e.g., load dump) do not exceed 37 V at the cathode pin.

Can TL431AIL5T replace TL431CL5T in an existing design?

Yes, TL431AIL5T is a direct functional and pin-compatible replacement for TL431CL5T, with identical SOT23-5 footprint and electrical behavior. The key upgrade is extended temperature range (−40 °C to +125 °C vs. 0 °C to +70 °C) and AEC-Q100 qualification, making it suitable for automotive deployment without layout changes.

How does the NC pin configuration affect PCB layout?

Pins 4 and 5 are internally unconnected and must remain floating or be tied to GND-never driven or connected to active signals. This allows routing flexibility: unused pins may be omitted from copper pours or used as thermal relief pads, but no net connectivity is required. Leaving them unconnected has no electrical impact.

Is external compensation required for stability with capacitive loads?

No external compensation is required for loads ≤10 µF, as confirmed by ST's stability testing (Figure 21). For larger capacitors (>10 µF), a series resistor (typically 1–10 Ω) between cathode and capacitor improves phase margin. The SOT23-5 package's low inductance further enhances high-frequency stability in compact automotive layouts.

TL431AIL5T Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Package/Case:: SC-74A, SOT-753

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:: ±1%

Temperature Coefficient:: -

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 700 µA

Operating Temperature:: -40°C ~ 105°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-5

TL431AIL5T FAQ

1.How can I place an order for TL431AIL5T through Aetrix?

Please submit a Request for Quotation (RFQ) for TL431AIL5T 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 TL431AIL5T reliable?

The price and inventory of TL431AIL5T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431AIL5T is usually 5 days.

3.What payment methods are accepted for TL431AIL5T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431AIL5T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TL431AIL5T?

TL431AIL5T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TL431AIL5T 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 TL431AIL5T?

For technical support, including TL431AIL5T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431AIL5T requirements.

6.How does Aetrix verify that TL431AIL5T is sourced from the original manufacturer or authorized distributors?

All TL431AIL5T 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 TL431AIL5T meets industry standards.

7.What is the process for return or replacement of TL431AIL5T?

All TL431AIL5T units undergo pre-shipment inspection (PSI). If there is an issue with TL431AIL5T, 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 TL431AIL5T part is unused and in its original packaging.

Return procedure for TL431AIL5T:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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