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STMicroelectronics TL431CZ-AP
- Part No.:
- TL431CZ-AP
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- TO-226-2, TO-92-2 (TO-226AC) Formed Leads
- Datasheet:
-
TL431CZ-AP.pdf
- Description:
- IC VREF SHUNT ADJ 2.21% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:8,253
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Product details
Overview
TL431CZ-AP 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, with 2% initial voltage accuracy, 1 mA to 100 mA sink current capability, and 0.22 Ω typical dynamic impedance for precision feedback in automotive power supplies.
For engineers reviewing the TL431CZ-AP datasheet, TL431CZ-AP pinout, TL431CZ-AP application, or TL431CZ-AP equivalent, this device serves as a temperature-stable, low-impedance voltage reference for closed-loop regulation in battery management, engine control units, and industrial DC-DC converters where -40 °C to +125 °C operation and automotive qualification are required.
Technical Context
The TL431CZ-AP operates as a three-terminal adjustable shunt regulator: its REF pin senses input voltage against an internal 2.5 V bandgap reference; cathode sinks current when REF exceeds threshold; anode connects to ground or return path. It functions across 1–100 mA cathode current with guaranteed stability up to 100 kHz.
Its architecture enables programmable output voltage (VOUT = VREF × (1 + R1/R2)) without external op-amps, while maintaining ±17 mV reference deviation over -40 °C to +125 °C and <1.8 µA reference input current - enabling high-impedance resistor networks and low-power sensing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VREF Accuracy | ±2% at 25 °C - sets absolute output tolerance for feedback loops using external resistors |
| Output Voltage Range | 2.5 V to 36 V - programmable via two external resistors, supporting wide-input DC-DC and LDO designs |
| Cathode Current Range | 1 mA to 100 mA - defines minimum load for regulation and maximum sink capacity for error amplifier drive |
| Dynamic Impedance | 0.22 Ω typical - ensures stable loop response and low output ripple under transient load changes |
| Temp. Range | -40 °C to +125 °C - validated for under-hood automotive environments and industrial edge controllers |
| Reference Input Current | ≤ 4 µA max - permits use of high-value feedback resistors (>1 MΩ), reducing power loss and thermal drift |
| Voltage Deviation | ±17 mV over full temp range - guarantees ≤0.7% total reference drift in closed-loop systems |
Pinout & Package
TL431CZ-AP uses TO-92 plastic package (bulk or ammopack), with 3 leads: Cathode (pin 1), Anode (pin 2), Reference (pin 3) - verified per Figure 1 (top view) in ST DocID4467 Rev 17.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 1) | Sink output terminal | Connects to regulated rail or error amplifier output; carries full load current to ground path |
| Anode (Pin 2) | Ground/return path | Reference return node; must be low-impedance to avoid regulation error from IR drop |
| Reference (Pin 3) | Feedback input | Senses divided output voltage; internal comparator compares to 2.5 V bandgap reference |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualified | Validated for automotive applications including ECU, BCM, and ADAS power rails |
| Adjustable output (2.5–36 V) | Enables single BOM part across multiple output voltages without redesigning feedback network |
| 0.22 Ω dynamic impedance | Minimizes output voltage perturbation during fast load transients in switching regulators |
| 1 mA min. cathode current | Allows reliable regulation even with high-resistance feedback dividers and light loads |
| Low IREF (≤4 µA) | Reduces resistor-divider power dissipation and self-heating errors in precision references |
Applications
| Automotive Battery Monitor | Industrial DC-DC Feedback |
|---|---|
Use Scenario: Monitoring 12 V lead-acid battery voltage in start-stop systems with microcontroller ADC input. IC Role / Device Role / Timing Role: Shunt reference providing stable 5 V reference for ADC and biasing voltage divider. Use Value: Maintains ±0.7% reference accuracy across -40 °C to +125 °C, eliminating calibration drift in under-hood sensors. |
Use Scenario: Output voltage regulation in isolated flyback converter powering PLC I/O modules. IC Role / Device Role / Timing Role: Secondary-side voltage reference feeding optocoupler feedback to primary controller. Use Value: 0.22 Ω dynamic impedance ensures tight regulation (<±1%) despite transformer leakage and opto CTR variation. |
| Engine Control Unit (ECU) Power Rail | Programmable Lab Power Supply |
Use Scenario: Generating precise 3.3 V and 5 V rails for MCU and CAN transceivers in diesel ECU. IC Role / Device Role / Timing Role: Adjustable shunt reference setting feedback point for synchronous buck controller. Use Value: 2% initial accuracy and ±17 mV temp drift enable single-point factory calibration over full operating range. |
Use Scenario: User-adjustable output (1.25–30 V) in benchtop linear power supply with digital potentiometer interface. IC Role / Device Role / Timing Role: Core voltage reference defining output setpoint via DAC-controlled resistor network. Use Value: Low 4 µA reference current allows direct connection to 10-bit DAC outputs without buffer amplifiers. |
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-AP | 1% initial accuracy (vs. 2%), same TO-92 package and temp range | Better suited for high-precision feedback where <±10 mV reference error is critical | Select when tighter initial tolerance justifies cost premium and layout remains unchanged |
| TL431IZ-AP | Same 2% accuracy but rated for -40 °C to +105 °C (vs. +125 °C) | Limited to cabin-mounted automotive modules or industrial controls below 105 °C ambient | Choose only if thermal derating confirms junction temp stays ≤105 °C in final enclosure |
Compared with TL431CZ-AP, TL431ACZ-AP improves reference accuracy by 1% without changing footprint or thermal design, while TL431IZ-AP reduces temperature capability by 20 °C - making TL431CZ-AP optimal for under-hood applications requiring full AEC-Q100 automotive grade performance.
Availability
TL431CZ-AP is available at Aetrix Electronics and suitable for automotive power supplies, industrial DC-DC converters, and battery management systems requiring stable component supply with AEC-Q100 qualification and extended temperature support.
Supply support for TL431CZ-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 designing and manufacturing microcontrollers, power ICs, analog components, and automotive-grade devices with focus on energy efficiency and reliability.
The TL431 product line delivers precision, temperature-stable shunt references for feedback control in automotive, industrial, and consumer power systems - engineered for robustness across harsh thermal and electrical environments.
FAQ
What is the maximum cathode-to-anode voltage for TL431CZ-AP?
The absolute maximum cathode-to-anode voltage is 37 V, with recommended operating range up to 36 V. Exceeding 37 V risks permanent damage. This rating enables use in 24 V and 36 V automotive systems and industrial SMPS outputs, provided proper heatsinking is applied above 100 mA sink current.
Can TL431CZ-AP replace TL431CZ in existing designs?
Yes - TL431CZ-AP is identical to TL431CZ in electrical specs, pinout, and package; the "-AP" suffix denotes ammopack packaging (tape-and-reel compatible format), not functional difference. No schematic or layout changes are needed, and it maintains full compatibility with legacy TL431CZ-based PCBs and firmware.
How does the 2% voltage accuracy affect output regulation in a 12 V power supply?
With 2% VREF accuracy and typical resistor tolerance, total output error is ≤±2.5% at 12 V - i.e., ±300 mV. This meets Class III industrial and most automotive auxiliary rail requirements. For tighter tolerance, pair with 0.5% feedback resistors or upgrade to TL431ACZ-AP.
Is external compensation required when using TL431CZ-AP with optocouplers?
No external compensation is required for basic optocoupler feedback in flyback converters; the TL431CZ-AP's inherent phase margin (≥60° at 10 kHz) and 0.22 Ω impedance provide stable loop behavior. However, for >500 kHz switching or capacitive loads >1 nF, add a 100 pF capacitor from cathode to reference per Figure 21 in ST DocID4467.
TL431CZ-AP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- TO-226-2, TO-92-2 (TO-226AC) Formed Leads
- Series:
- -
- Packaging:
- Cut Tape (CT)
- 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-AP FAQ
1.How can I place an order for TL431CZ-AP through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431CZ-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 TL431CZ-AP reliable?
The price and inventory of TL431CZ-AP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431CZ-AP is usually 5 days.
3.What payment methods are accepted for TL431CZ-AP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431CZ-AP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431CZ-AP?
TL431CZ-AP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431CZ-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 TL431CZ-AP?
For technical support, including TL431CZ-AP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431CZ-AP requirements.
6.How does Aetrix verify that TL431CZ-AP is sourced from the original manufacturer or authorized distributors?
All TL431CZ-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 TL431CZ-AP meets industry standards.
7.What is the process for return or replacement of TL431CZ-AP?
All TL431CZ-AP units undergo pre-shipment inspection (PSI). If there is an issue with TL431CZ-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 TL431CZ-AP part is unused and in its original packaging.
Return procedure for TL431CZ-AP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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