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

STMicroelectronics TL431CZ

Name: TL431CZ
Brand: STMicroelectronics
SKU: TL431CZ
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TL431CZ

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

Package:: TO-226-3, TO-92-3 (TO-226AA)

Datasheet:: TL431CZ.pdf

Description:: IC VREF SHUNT ADJ 2.21% TO92-3

Quantity:: RFQ Add To RFQ list

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Inventory:4,604

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Product details

Overview

TL431CZ from STMicroelectronics is an AEC-Q100 qualified adjustable shunt voltage reference in TO-92 plastic 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 precision across 0 °C to +70 °C ambient range - used in automotive power supply feedback loops and industrial DC-DC regulation.

For engineers reviewing the TL431CZ datasheet, TL431CZ pinout, TL431CZ application, or TL431CZ equivalent, key selection considerations include its TO-92 thermal resistance (R_thJA = 200 °C/W), cathode-to-anode voltage rating (37 V), minimum regulation current (0.5 mA), and automotive-grade temperature stability compliance.

Technical Context

The TL431CZ operates as a three-terminal adjustable shunt regulator with internal 2.5 V reference, error amplifier, and NPN output stage. Its regulation relies on external resistor divider feedback to the REF pin, enabling precise voltage setting without trimming.

It maintains stable operation over 1–100 mA cathode current with low dynamic impedance (0.22 Ω) and exhibits predictable temperature drift (±17 mV over full operating range), making it suitable for closed-loop feedback in isolated flyback and buck-derived supplies.

Key Specifications

Parameter	Value and Actual Design Meaning
Reference Voltage	2.47–2.52 V at 25 °C; sets base accuracy for all output configurations.
Output Voltage Range	2.5–36 V; programmable via external R1/R2 divider - enables flexible supply rail generation.
Cathode Current Range	1–100 mA; defines usable load current range while maintaining regulation.
Dynamic Impedance	0.22 Ω typical; ensures minimal output voltage variation under transient load changes.
Voltage Precision	±2% over 0 °C to +70 °C; specifies maximum initial error before calibration or trimming.
Thermal Resistance	R_thJA = 200 °C/W (TO-92); determines junction temperature rise under power dissipation.
Max Cathode-Anode Voltage	37 V; sets absolute upper limit for safe operation in high-voltage feedback paths.

Pinout & Package

TL431CZ uses the TO-92 plastic package (3-pin, through-hole), with standardized pinout: Pin 1 = Anode, Pin 2 = Cathode, Pin 3 = Reference (REF). The package supports manual soldering and wave soldering, and provides adequate thermal performance for ≤300 mW dissipation in free-air conditions.

Pin/Terminal	Circuit Role	Design Meaning
Anode (Pin 1)	Current return path	Connected to system ground or low-side reference; completes shunt current loop.
Cathode (Pin 2)	Regulated output node	Sinks current to maintain set voltage; connects to feedback point of switching controller.
Reference (Pin 3)	Feedback input	High-impedance input sensing divider voltage; triggers regulation when ≥2.47 V applied.

Key Features

Feature	Design Value
Adjustable output voltage	2.5–36 V via two-resistor divider - eliminates need for multiple fixed-reference SKUs.
AEC-Q100 qualification	Validated for automotive applications including engine control and body electronics.
Low dynamic impedance	0.22 Ω typical - improves transient response and reduces output ripple in feedback networks.
Wide operating current	1–100 mA cathode range - accommodates both low-power sensors and high-current SMPS designs.
Stable over temperature	±17 mV reference deviation from 0 °C to +70 °C - ensures consistent regulation across commercial environments.

Applications

Automotive Power Supply Feedback

Industrial DC-DC Converter Regulation

Use Scenario: Closed-loop voltage feedback in 12 V/48 V automotive DC-DC converters supplying infotainment and ADAS subsystems.

IC Role / Device Role / Timing Role: Shunt reference providing precise 5 V or 3.3 V feedback to primary-side controller IC.

Use Value: Enables ±2% output regulation despite battery voltage fluctuations (9–16 V) and load transients up to 5 A.

Use Scenario: Output voltage stabilization in isolated flyback converters powering PLC I/O modules and sensor interfaces.

IC Role / Device Role / Timing Role: Secondary-side voltage reference feeding optocoupler feedback path to primary PWM controller.

Use Value: Maintains <1% output deviation across -25 °C to +70 °C ambient and 10–100% load steps.

Programmable Overvoltage Protection

Low-Cost Voltage Monitor Circuit

Use Scenario: Standalone overvoltage cutoff for 24 V industrial power rails protecting downstream FPGAs and microcontrollers.

IC Role / Device Role / Timing Role: Adjustable threshold detector triggering MOSFET gate shutdown via comparator interface.

Use Value: Configurable trip point (e.g., 26.5 V ±0.5 V) with <10 µs response time using external hysteresis network.

Use Scenario: Brown-out detection and reset generation in battery-powered instrumentation with 3.0 V nominal supply.

IC Role / Device Role / Timing Role: Precision reference input to comparator driving microcontroller reset pin.

Use Value: Accurate 2.95 V threshold detection with <±5 mV tolerance, eliminating need for external trimming.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431ACZ	±1% initial voltage precision vs. TL431CZ's ±2%; otherwise identical pinout, package, and specs.	Required where tighter output tolerance is mandated (e.g., medical power supplies).	Select TL431ACZ when system-level accuracy demands sub-1% reference error without redesign.
TL431BZ	±0.5% precision and extended -40 °C to +125 °C temp range; TO-92 package same footprint.	Suitable for under-hood automotive modules requiring higher accuracy and wider thermal margin.	Choose TL431BZ only if both enhanced precision and full automotive temperature range are required.

Compared with TL431CZ, TL431ACZ offers improved accuracy at no cost penalty or layout change, while TL431BZ adds both precision and extended temperature capability - making TL431CZ optimal for cost-sensitive commercial and light-industrial applications where ±2% tolerance suffices.

Availability

TL431CZ is available at Aetrix Electronics and suitable for automotive power supply feedback, industrial DC-DC converter regulation, and programmable overvoltage protection requiring stable component supply and long-term production continuity.

Supply support for TL431CZ 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, designing and manufacturing analog, MCU, power, and sensor solutions for automotive, industrial, and consumer markets.

The TL431 product line delivers precision, adjustable shunt references optimized for feedback, monitoring, and protection circuits in cost-constrained, high-reliability power systems.

FAQ

What is the maximum cathode-to-anode voltage for TL431CZ?

The absolute maximum cathode-to-anode voltage (V_KA) is 37 V. Exceeding this risks permanent damage. In normal operation, the device regulates with V_KA ≥ V_REF (≥2.47 V) and is commonly used with 5–36 V across cathode and anode in feedback applications.

Can TL431CZ be used in place of TL431ACZ?

Yes, TL431CZ is pin- and package-compatible with TL431ACZ and shares identical electrical behavior except for initial voltage precision (±2% vs. ±1%). System-level testing is recommended if the design relies on tighter reference tolerance for stability or accuracy.

What is the minimum cathode current needed for regulation?

The minimum cathode current (I_min) is 0.5 mA at 25 °C, rising to 1 mA over the full 0 °C to +70 °C range. Below this, the device exits regulation and V_KA rises toward the supply rail - critical for low-power standby modes.

Does TL431CZ require external compensation for stability?

No external compensation is required for basic shunt regulation. However, when driving capacitive loads >10 nF or used in optocoupler feedback loops, a series resistor (10–100 Ω) between cathode and opto-LED improves phase margin and prevents oscillation per ST application guidance.

TL431CZ Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Package/Case:: TO-226-3, TO-92-3 (TO-226AA)

Series:: -

Packaging:: Bulk

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:: 0°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

TL431CZ FAQ

1.How can I place an order for TL431CZ through Aetrix?

Please submit a Request for Quotation (RFQ) for TL431CZ 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 TL431CZ reliable?

The price and inventory of TL431CZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431CZ is usually 5 days.

3.What payment methods are accepted for TL431CZ?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431CZ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TL431CZ?

TL431CZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TL431CZ 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 TL431CZ?

For technical support, including TL431CZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431CZ requirements.

6.How does Aetrix verify that TL431CZ is sourced from the original manufacturer or authorized distributors?

All TL431CZ 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 TL431CZ meets industry standards.

7.What is the process for return or replacement of TL431CZ?

All TL431CZ units undergo pre-shipment inspection (PSI). If there is an issue with TL431CZ, 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 TL431CZ part is unused and in its original packaging.

Return procedure for TL431CZ:

1.Submit a request within 90 days.

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

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