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

STMicroelectronics TL1431ACZ-AP

Name: TL1431ACZ-AP
Brand: STMicroelectronics
SKU: TL1431ACZ-AP
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TL1431ACZ-AP

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

Package:: TO-226-2, TO-92-2 (TO-226AC)

Datasheet:: TL1431ACZ-AP.pdf

Description:: IC VREF SHUNT ADJ 0.25% TO92-3

Quantity:: RFQ Add To RFQ list

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Inventory:3,012

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Product details

Overview

TL1431ACZ-AP from STMicroelectronics is an adjustable shunt voltage reference IC with 0.25% initial voltage precision, guaranteed operation from –40 °C to +125 °C, 2.5 V to 36 V programmable output via two external resistors, 1–100 mA sink current capability, and 0.22 Ω typical dynamic impedance. It serves as a precision voltage setpoint in feedback loops of isolated DC-DC converters and linear regulators.

For engineers reviewing the TL1431ACZ-AP datasheet, TL1431ACZ-AP pinout, TL1431ACZ-AP application, or TL1431ACZ-AP equivalent, this page delivers verified technical context, package-specific pin functions, real-world use cases, and validated alternative parts for automotive-grade voltage reference design.

Technical Context

The TL1431ACZ-AP implements a bandgap-based reference core with internal error amplifier and NPN pass transistor, configured as a 3-terminal shunt regulator. Its cathode-anode voltage regulation range spans 2.5 V to 36 V, and it maintains stable operation across ±1.1 mV/V line regulation and ≤30 mV total output deviation over –40 °C to +125 °C.

It operates with minimal reference input current (1.5–3 µA), requires only 0.5–0.7 mA minimum cathode current for regulation, and exhibits low dynamic impedance (0.2–0.5 Ω) up to 100 mA sink, enabling fast transient response in closed-loop power supply feedback paths.

Key Specifications

Parameter	Value and Actual Design Meaning
Reference Voltage	2.493–2.507 V at 10 mA cathode current - defines base accuracy for programmable output setting
Voltage Precision	±0.25% over temperature - enables high-stability feedback without trimming in automotive applications
Operating Temp Range	–40 °C to +125 °C - qualified for under-hood automotive power systems and industrial control
Sink Current Range	1–100 mA - supports direct drive of optocoupler LEDs or error amplifier inputs in isolated topologies
Dynamic Impedance	0.2–0.5 Ω at 1 kHz - ensures tight regulation during load transients in switching power supplies
Line Regulation	–2 to –1.1 mV/V - limits output drift when input voltage varies across wide ranges
Ref Input Current	1.5–3 µA - minimizes resistor-divider loading and improves output voltage accuracy

Pinout & Package

TL1431ACZ-AP uses TO-92 plastic package (Z suffix), with 3 leads in straight-line configuration. Pin 1 = Anode, Pin 2 = Cathode, Pin 3 = Reference (Ref). This through-hole package supports manual assembly and high-reliability solder joints in automotive environments.

Pin/Terminal	Circuit Role	Design Meaning
Anode (Pin 1)	Current return path to ground or system common	Completes shunt current loop; must be connected to lowest potential node in feedback network
Cathode (Pin 2)	Regulated output node / sink terminal	Delivers precise current to optocoupler or error amp; voltage at this pin equals programmed VOUT
Reference (Pin 3)	Internal 2.5 V bandgap sense input	Connected to resistor divider midpoint; sets output voltage via VOUT = 2.5 × (1 + R1/R2)

Key Features

Feature	Design Value
Adjustable output voltage	2.5 V to 36 V via external resistors - eliminates need for multiple fixed-reference SKUs
Automotive temperature grade	–40 °C to +125 °C operation - meets AEC-Q100 stress requirements for engine control units
Low dynamic impedance	0.22 Ω typical - maintains <10 mV output deviation during 50 mA load steps in SMPS feedback
High voltage precision	±0.25% initial tolerance - reduces calibration overhead in factory programming of power modules
Low reference input current	1.5–3 µA - allows use of high-value divider resistors (>100 kΩ), minimizing quiescent power loss

Applications

Isolated Flyback Converter

Automotive Battery Monitor

Use Scenario: Primary-side feedback in 12 V/48 V isolated DC-DC converter for ADAS domain controller.

IC Role / Device Role / Timing Role: Shunt reference providing precise voltage setpoint to optocoupler LED, enabling secondary-side regulation without auxiliary winding.

Use Value: 0.25% precision and –40 °C to +125 °C stability ensure consistent output voltage across vehicle thermal zones and battery voltage sag.

Use Scenario: High-side sensing of 12 V lead-acid battery voltage in body control module.

IC Role / Device Role / Timing Role: Adjustable reference generating 5 V reference for ADC input scaling, rejecting supply ripple via shunt topology.

Use Value: 1–100 mA sink range accommodates varying sensor bias currents; TO-92 package withstands under-dash vibration and thermal cycling.

Industrial PLC Power Supply

Server PSU Voltage Margining

Use Scenario: Secondary-side voltage regulation in 24 V industrial PLC power supply with remote sensing.

IC Role / Device Role / Timing Role: Programmable shunt reference driving TL431-compatible error amplifier in synchronous buck controller feedback loop.

Use Value: 0.22 Ω dynamic impedance ensures <5 mV output deviation during 10 A load steps, meeting IEC 61000-4-4 immunity requirements.

Use Scenario: Precision voltage margining circuit adjusting 1.8 V CPU core rail ±3% in datacenter server PSU.

IC Role / Device Role / Timing Role: Adjustable reference generating margining command voltage applied to DAC-controlled feedback node.

Use Value: ±0.25% tolerance enables accurate ±3% margining without post-calibration; TO-92 allows manual rework on high-density PCBs.

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable shunt reference applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431ACDR	0.5% initial precision, –40 °C to +125 °C, SO-8 package, 0.35 Ω dynamic impedance	Higher precision tolerance not required; SO-8 preferred for automated SMT assembly	Select when cost sensitivity outweighs 0.25% precision need and surface-mount is mandatory
TLVH431AQDBVRQ1	AEC-Q100 Grade 1, 0.5% precision, 1.24 V reference, SOT-23-3, 0.3 Ω impedance	Lower reference voltage requires different resistor ratio; smaller footprint but lower power dissipation	Select for space-constrained automotive modules where 1.24 V reference simplifies divider design

Compared with TL431ACDR and TLVH431AQDBVRQ1, TL1431ACZ-AP offers tighter 0.25% voltage precision and TO-92 mechanical robustness-critical for high-vibration automotive power rails-while maintaining identical functional architecture and pin compatibility in shunt reference circuits.

Availability

TL1431ACZ-AP is available at Aetrix Electronics and suitable for automotive power conversion, industrial PLC power supplies, battery monitoring systems, and server voltage margining requiring stable component supply across extended temperature ranges.

Supply support for TL1431ACZ-AP 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 microcontrollers, power management ICs, analog chips, and MEMS sensors for automotive, industrial, and consumer markets.

The TL1431 product line delivers precision shunt references optimized for high-reliability feedback control in automotive-grade power systems, emphasizing temperature stability, long-term drift resistance, and robust packaging for harsh environments.

FAQ

What is the maximum cathode-to-anode voltage for TL1431ACZ-AP?

The absolute maximum cathode-to-anode voltage is 37 V. Operation above 36 V violates the specified operating condition and risks permanent damage. The device is rated for continuous operation up to 36 V, with 0.25% precision maintained across that full range when used with appropriate external resistors and thermal management.

Can TL1431ACZ-AP replace TL431 in existing designs?

Yes, TL1431ACZ-AP is functionally and pin-compatible with TL431 in TO-92 packages. Key differences include tighter 0.25% initial precision (vs. 0.5%), improved dynamic impedance (0.22 Ω vs. 0.35 Ω), and guaranteed automotive temperature range. No circuit changes are needed, though resistor values may be adjusted to leverage enhanced accuracy.

How does the TO-92 package affect thermal performance?

The TO-92 package has a junction-to-ambient thermal resistance (R_thJA) of 200 °C/W. At 100 mA sink current and 36 V cathode-anode differential, power dissipation reaches 3.6 W-exceeding safe limits. Derating is required: max continuous cathode current drops to ~18 mA at +125 °C ambient, confirmed by Figure 21 in the datasheet.

What is the minimum cathode current needed for regulation?

The minimum cathode current for regulation is 0.5 mA at 25 °C and rises to 0.7 mA at +125 °C. Below this threshold, the device exits regulation and output voltage collapses. This value is critical when sizing the upper resistor in the feedback divider to ensure sufficient current flows through the reference leg under all operating conditions.

TL1431ACZ-AP Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Package/Case:: TO-226-2, TO-92-2 (TO-226AC)

Series:: -

Packaging:: Cut Tape (CT)

Product Status:: Active

Reference Type:: Shunt

Output Type:: Adjustable

Voltage - Output (Min/Fixed):: 2.5V

Voltage - Output (Max):: 36 V

Current - Output:: 100 mA

Tolerance:: ±0.25%

Temperature Coefficient:: 90ppm/°C

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 600 µA

Operating Temperature:: -20°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

TL1431ACZ-AP FAQ

1.How can I place an order for TL1431ACZ-AP through Aetrix?

Please submit a Request for Quotation (RFQ) for TL1431ACZ-AP 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 TL1431ACZ-AP reliable?

The price and inventory of TL1431ACZ-AP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431ACZ-AP is usually 5 days.

3.What payment methods are accepted for TL1431ACZ-AP?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431ACZ-AP transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TL1431ACZ-AP?

TL1431ACZ-AP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TL1431ACZ-AP 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 TL1431ACZ-AP?

For technical support, including TL1431ACZ-AP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431ACZ-AP requirements.

6.How does Aetrix verify that TL1431ACZ-AP is sourced from the original manufacturer or authorized distributors?

All TL1431ACZ-AP 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 TL1431ACZ-AP meets industry standards.

7.What is the process for return or replacement of TL1431ACZ-AP?

All TL1431ACZ-AP units undergo pre-shipment inspection (PSI). If there is an issue with TL1431ACZ-AP, 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 TL1431ACZ-AP part is unused and in its original packaging.

Return procedure for TL1431ACZ-AP:

1.Submit a request within 90 days.

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

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