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STMicroelectronics TL431ACZ
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- Part No.:
- TL431ACZ
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- TO-226-2, TO-92-2 (TO-226AC)
- Datasheet:
-
TL431ACZ.pdf
- Description:
- IC VREF SHUNT ADJ 1% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:1,981
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Product details
Overview
TL431ACZ from STMicroelectronics is an AEC-Q100 qualified adjustable shunt voltage reference in TO-92 plastic package, delivering 1% initial voltage precision (2.47–2.52 V at 25 °C), 2.5–36 V programmable output via two external resistors, and 1–100 mA sink current capability for automotive power supply feedback loops.
For engineers reviewing the TL431ACZ datasheet, TL431ACZ pinout, TL431ACZ application, or TL431ACZ equivalent, this device serves as a temperature-stable, low-impedance (0.22 Ω typical) voltage reference in automotive-grade linear regulators, battery management systems, and isolated flyback controller feedback networks where -40 °C to +125 °C operation and ±1% tolerance are required.
Technical Context
The TL431ACZ implements a precision 2.5 V bandgap reference with internal error amplifier and NPN transistor output stage, configured as a three-terminal shunt regulator. Its reference input (REF) senses external resistor divider voltage, while cathode (K) sinks current to maintain regulated output across the anode (A)–cathode (K) terminals.
It operates over 1–100 mA cathode current with guaranteed dynamic impedance ≤0.5 Ω up to 1 kHz, reference input current ≤4 µA (typ), and thermal stability maintained by AEC-Q100-compliant process and packaging-enabling stable closed-loop control in automotive DC-DC converters and industrial SMPS feedback paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.47–2.52 V at 25 °C (1% accuracy); sets precise feedback threshold for output regulation |
| Output Voltage Range | 2.5–36 V (programmable via R1/R2 divider); supports wide-range power rail monitoring and adjustment |
| Cathode Current Range | 1–100 mA; enables direct drive of optocoupler LEDs or error amplifier inputs without external buffering |
| Dynamic Impedance | 0.22 Ω typical (≤0.5 Ω max); ensures minimal output voltage perturbation under load transients |
| Temp. Range | -40 °C to +125 °C (automotive grade); guarantees stable reference performance in engine bay and ADAS modules |
| Ref Input Current | ≤4 µA typical at 25 °C; minimizes divider current loss and improves high-resistance programming flexibility |
| Voltage Deviation | ±15 mV over full temp range; translates to <0.6% total variation in 2.5 V reference, critical for tight-tolerance feedback |
Pinout & Package
TL431ACZ uses TO-92 plastic package (3-pin, through-hole), with standardized pinout per Figure 1: Pin 1 = Anode (A), Pin 2 = Cathode (K), Pin 3 = Reference (REF). Thermal resistance junction-to-ambient is 200 °C/W, supporting moderate-power dissipation in compact layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Reference ground return path | Connected to system ground or output rail common; completes shunt current loop with cathode |
| Cathode (Pin 2) | Current sink output terminal | Sinks regulated current to maintain REF voltage; drives optocoupler LED or error amp input directly |
| Reference (Pin 3) | Precision voltage sense input | Compares external resistor divider voltage against internal 2.5 V bandgap; triggers cathode conduction when exceeded |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualification | Validated for automotive applications including engine control units and body electronics requiring reliability at 125 °C junction |
| Adjustable 2.5–36 V output | Enables single BOM part to support multiple output rails (e.g., 3.3 V, 5 V, 12 V, 24 V) via resistor selection only |
| 0.22 Ω typical dynamic impedance | Provides fast transient response and low noise injection into feedback loop of switching regulators |
| 1–100 mA cathode sink range | Eliminates need for external transistor in most optocoupler-based isolated feedback designs |
| Low 4 µA reference input current | Permits use of high-value resistor dividers (>1 MΩ), reducing power loss and improving noise immunity |
Applications
| Automotive Power Supply | Industrial SMPS Feedback |
|---|---|
|
Use Scenario: Regulating 12 V battery-derived rail in engine control module with wide ambient temperature swing. IC Role / Device Role / Timing Role: Shunt reference providing precise feedback voltage to UC384x PWM controller via optocoupler. Use Value: Maintains ±1% output accuracy across -40 °C to +125 °C, ensuring ECU logic voltage stability despite thermal cycling. |
Use Scenario: Closed-loop voltage regulation in 48 V telecom rectifier with isolation barrier. IC Role / Device Role / Timing Role: Primary-side voltage reference driving PC817 optocoupler to transmit error signal across transformer barrier. Use Value: 0.22 Ω dynamic impedance suppresses feedback loop phase shift, enabling stable 500 kHz switching without compensation redesign. |
| Battery Management System | Programmable Linear Regulator |
|
Use Scenario: Cell voltage monitoring and balancing reference in 12S Li-ion pack for EV auxiliary systems. IC Role / Device Role / Timing Role: Precision threshold detector comparing cell voltage against programmable 3.6 V reference. Use Value: ±15 mV reference deviation over temperature ensures consistent cell overvoltage trip points across full vehicle operating range. |
Use Scenario: Adjustable 3.3–15 V linear regulator for FPGA I/O bank supply with fine-grained voltage tuning. IC Role / Device Role / Timing Role: Shunt reference setting output via external R1/R2 network; paired with pass transistor (e.g., BD139). Use Value: 1% initial tolerance and low 4 µA input current allow accurate, low-power voltage programming without 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 |
|---|---|---|---|
| TL431CZ | 2% initial voltage tolerance (2.44–2.55 V), commercial temp range (0 to +70 °C) | Not qualified for automotive or extended industrial environments; unsuitable for under-hood use | Select only for cost-sensitive, non-automotive applications with relaxed accuracy and temperature requirements |
| TL431BIZ | 0.5% initial tolerance (2.483–2.507 V), same -40 to +125 °C range, SOT-23-3 package | Surface-mount footprint; higher precision but lower power dissipation due to smaller package | Choose when board space is constrained and tighter voltage accuracy is mandatory, accepting reduced thermal margin |
Compared with TL431ACZ, TL431CZ trades automotive qualification and 1% accuracy for lower cost, while TL431BIZ upgrades precision to 0.5% and switches to SMT-but sacrifices TO-92's higher thermal mass and through-hole robustness in vibration-prone automotive assemblies.
Availability
TL431ACZ is available at Aetrix Electronics and suitable for automotive power supplies, industrial SMPS feedback circuits, and battery management systems requiring stable component supply with AEC-Q100 compliance and extended temperature operation.
Supply support for TL431ACZ 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 ICs, sensors, and analog components for automotive, industrial, and consumer markets.
The TL431 product line delivers precision programmable shunt references optimized for feedback control in power conversion systems-specifically engineered to meet automotive AEC-Q100 stress testing and long-term reliability requirements.
FAQ
What is the maximum cathode-to-anode voltage rating for TL431ACZ?
The absolute maximum cathode-to-anode voltage (VKA) is 37 V. Operation above this risks permanent damage. In practice, the device is rated for continuous operation up to 36 V across the cathode–anode terminals, making it suitable for 24 V and 36 V automotive and industrial bus applications.
Can TL431ACZ be used without an external resistor divider?
No-it requires an external resistor divider between cathode and anode to set the output voltage. The reference pin must sense a voltage derived from that divider; floating or directly tied REF will prevent regulation. Minimum cathode current (0.5 mA) must also be maintained for stable operation.
How does TL431ACZ differ from TL432 variants?
TL432 is functionally identical to TL431 but features a different pinout in SOT-23-3: REF and CATHODE are swapped versus TL431. TL431ACZ (TO-92) has no TL432 counterpart in that package-TL432 variants exist only in SOT-23-3 and SOT-23-5, and are marked separately (e.g., TL432ACL3T).
Is TL431ACZ pin-compatible with older TL431 versions from other manufacturers?
Yes-TL431ACZ maintains standard TO-92 pinout (Anode–Cathode–REF) and electrical specifications aligned with industry-standard TL431 behavior. However, its AEC-Q100 qualification, 1% tolerance, and -40 °C to +125 °C range exceed legacy commercial-grade parts, so validation in target thermal and reliability conditions remains essential.
TL431ACZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- TO-226-2, TO-92-2 (TO-226AC)
- 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:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 600 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL431ACZ FAQ
1.How can I place an order for TL431ACZ through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431ACZ 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 TL431ACZ reliable?
The price and inventory of TL431ACZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431ACZ is usually 5 days.
3.What payment methods are accepted for TL431ACZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431ACZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431ACZ?
TL431ACZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431ACZ 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 TL431ACZ?
For technical support, including TL431ACZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431ACZ requirements.
6.How does Aetrix verify that TL431ACZ is sourced from the original manufacturer or authorized distributors?
All TL431ACZ 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 TL431ACZ meets industry standards.
7.What is the process for return or replacement of TL431ACZ?
All TL431ACZ units undergo pre-shipment inspection (PSI). If there is an issue with TL431ACZ, 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 TL431ACZ part is unused and in its original packaging.
Return procedure for TL431ACZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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