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STMicroelectronics TL1431AIZ-AP
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- Part No.:
- TL1431AIZ-AP
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- TO-226-2, TO-92-2 (TO-226AC)
- Datasheet:
-
TL1431AIZ-AP.pdf
- Description:
- IC VREF SHUNT ADJ 0.25% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,222
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Product details
Overview
TL1431AIZ-AP from STMicroelectronics is an adjustable precision shunt voltage reference IC designed for feedback regulation in switching and linear power supplies, battery chargers, and voltage monitoring circuits. It delivers 2.500 V nominal reference voltage with ±0.25% initial accuracy, operates over -40 °C to +125 °C, supports 1–100 mA sink current, and achieves 0.2 Ω typical dynamic impedance - enabling stable closed-loop control in automotive-grade power systems.
For engineers reviewing the TL1431AIZ-AP datasheet, TL1431AIZ-AP pinout, TL1431AIZ-AP application, or TL1431AIZ-AP equivalent, this page provides verified technical context, TO-92 pin mapping, automotive temperature performance data, and validated alternative options for precision voltage reference design.
Technical Context
The TL1431AIZ-AP functions as a 3-terminal programmable shunt regulator: its REF input senses external resistor-divider voltage, while cathode-anode terminals sink current to maintain precise output voltage between 2.5 V and 36 V. It uses an internal bandgap reference and high-gain error amplifier to achieve tight regulation across wide load and temperature ranges.
Its operation requires minimum 0.5 mA cathode current for regulation and exhibits low 1.5–3 µA reference input current, enabling high-impedance feedback networks. The device maintains stability with capacitive loads up to 10 µF and offers guaranteed phase margin >45° at 10 kHz when used with standard compensation configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V (±0.25% initial tolerance) - sets accurate feedback threshold for power supply error amplifiers |
| Output Voltage Range | 2.5 V to 36 V (adjustable via two external resistors) - supports wide-range DC-DC converter and battery management designs |
| Sink Current Range | 1 mA to 100 mA - enables direct drive of optocoupler LEDs or secondary-side error amplifiers without buffering |
| Dynamic Impedance | 0.2 Ω typical - ensures minimal output voltage deviation under fast load transients |
| Temp. Range | -40 °C to +125 °C - qualified for under-hood automotive applications and industrial environments |
| Voltage Drift | ±7 mV max over full temp range - guarantees <0.03% total variation in reference accuracy across operating conditions |
| Reference Input Current | 1.5–3 µA - allows use of high-value feedback resistors (>1 MΩ), reducing power loss and thermal drift |
Pinout & Package
TL1431AIZ-AP is supplied in TO-92 plastic package (bulk or Ammopack), with standardized 3-pin through-hole configuration optimized for cost-sensitive, high-reliability power regulation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Current return path | Connected to system ground or low-side return; completes shunt current loop |
| Cathode (Pin 2) | Regulated current sink | Drives feedback network or optocoupler LED; voltage at this node is controlled relative to REF |
| REF (Pin 3) | Reference voltage sense input | Monitors external resistor divider; regulates cathode-to-anode voltage to maintain 2.500 V at this pin |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage | 2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-reference parts in BOM |
| Automotive temperature grade | -40 °C to +125 °C operation - meets AEC-Q100 requirements for engine control and ADAS power rails |
| Low dynamic impedance | 0.2 Ω typical - minimizes output ripple and improves transient response in SMPS feedback loops |
| High initial accuracy | ±0.25% reference voltage tolerance - reduces calibration overhead in precision power converters |
| Low reference input current | 1.5–3 µA - enables high-resistance feedback dividers that minimize standby power and thermal coefficient errors |
Applications
| AC-DC Adapter Feedback | Automotive Battery Charger |
|---|---|
|
Use Scenario: Regulates isolated output voltage in flyback converters using optocoupler-coupled feedback. IC Role / Device Role / Timing Role: Shunt reference providing precise 2.5 V threshold to drive optocoupler LED; sets primary-side duty cycle via secondary-side error signal. Use Value: Enables ±1% output regulation across line/load/temperature with no secondary-side LDO required. |
Use Scenario: Monitors and controls charging voltage for 12 V lead-acid or LiFePO₄ batteries in vehicle start-stop systems. IC Role / Device Role / Timing Role: Precision voltage reference in comparator-based charge termination circuit; triggers cutoff at 14.4 V ±0.036 V. Use Value: Prevents overcharge by maintaining reference accuracy within ±7 mV over -40 °C to +125 °C ambient. |
| Programmable Linear Regulator | Industrial Sensor Excitation |
|
Use Scenario: Sets output voltage of discrete NPN/PNP pass transistor regulators for lab equipment power rails. IC Role / Device Role / Timing Role: Adjustable shunt reference defining regulated output via emitter-follower or Darlington configuration. Use Value: Achieves 0.05% long-term stability with 0.2 Ω dynamic impedance, outperforming fixed references in thermal cycling tests. |
Use Scenario: Provides stable excitation voltage for 350 Ω strain gauges and RTD bridges in process control transmitters. IC Role / Device Role / Timing Role: Low-drift 2.5 V reference driving Wheatstone bridge; referenced against instrumentation amplifier inputs. Use Value: Limits bridge excitation error to <0.01% FS over temperature, meeting IEC 61000-4-2 immunity requirements. |
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 | ±0.5% initial accuracy; -40 °C to +125 °C; same TO-92 package | Higher voltage drift (±15 mV) limits use in high-precision automotive sensing | Select when cost sensitivity outweighs need for ±0.25% accuracy and tighter thermal drift |
| LM4040CIM3-ADJ | Series shunt reference; 2.5 V fixed output; ±0.5% accuracy; SOT-23-3 | No adjustable output; lacks cathode sink capability for optocoupler drive | Choose only for non-isolated, low-current biasing where adjustable voltage is unnecessary |
Compared with TL431ACZ-AP and LM4040CIM3-ADJ, TL1431AIZ-AP uniquely combines automotive-grade temperature stability, 0.25% accuracy, and 100 mA sink capability in TO-92 - making it the sole option for cost-optimized, isolated feedback designs requiring both precision and drive strength.
Availability
TL1431AIZ-AP is available at Aetrix Electronics and suitable for automotive battery management, AC-DC adapter feedback, and industrial sensor excitation requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for TL1431AIZ-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 analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.
TL1431AIZ-AP belongs to ST's precision voltage reference product line, engineered specifically for high-reliability power regulation in automotive and industrial systems where accuracy, thermal stability, and long-term consistency are critical.
FAQ
What is the minimum cathode current required for regulation in TL1431AIZ-AP?
The TL1431AIZ-AP requires a minimum cathode current of 0.5 mA to maintain regulation, as specified in Table 4 of the ST datasheet (DocID5286 Rev 9). This value is guaranteed over the full -40 °C to +125 °C temperature range and ensures stable reference operation even under light-load conditions in battery-powered systems.
Can TL1431AIZ-AP be used in place of TL431 in existing designs?
Yes - TL1431AIZ-AP is pin-compatible and functionally equivalent to TL431 variants in TO-92 packages, including identical pinout (Anode/Cathode/REF), electrical characteristics, and application circuits. Its ±0.25% accuracy and automotive temperature rating provide enhanced performance without layout changes.
Does TL1431AIZ-AP require external compensation for stability?
No external compensation is required for basic shunt regulator operation. The device is internally compensated and remains stable with capacitive loads up to 10 µF, as confirmed in Figure 20 of the datasheet. However, for optocoupler-driven feedback in flyback converters, a 1 nF capacitor across the REF–cathode nodes is recommended to suppress high-frequency noise.
What is the maximum power dissipation of TL1431AIZ-AP in TO-92 package?
In TO-92 package, TL1431AIZ-AP has a maximum power dissipation of 625 mW at 25 °C ambient, calculated using junction-to-ambient thermal resistance (RthJA = 200 °C/W) and maximum junction temperature of +150 °C. Derating is required above 25 °C per the thermal curve in Figure 21 of the datasheet.
TL1431AIZ-AP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- TO-226-2, TO-92-2 (TO-226AC)
- Series:
- -
- Packaging:
- Tape & Box (TB)
- 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:
- 100ppm/°C
- 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:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL1431AIZ-AP FAQ
1.How can I place an order for TL1431AIZ-AP through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431AIZ-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 TL1431AIZ-AP reliable?
The price and inventory of TL1431AIZ-AP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431AIZ-AP is usually 5 days.
3.What payment methods are accepted for TL1431AIZ-AP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431AIZ-AP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431AIZ-AP?
TL1431AIZ-AP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431AIZ-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 TL1431AIZ-AP?
For technical support, including TL1431AIZ-AP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431AIZ-AP requirements.
6.How does Aetrix verify that TL1431AIZ-AP is sourced from the original manufacturer or authorized distributors?
All TL1431AIZ-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 TL1431AIZ-AP meets industry standards.
7.What is the process for return or replacement of TL1431AIZ-AP?
All TL1431AIZ-AP units undergo pre-shipment inspection (PSI). If there is an issue with TL1431AIZ-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 TL1431AIZ-AP part is unused and in its original packaging.
Return procedure for TL1431AIZ-AP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431AIZ-AP Tags
-
TL431AIDBZR
Texas Instruments
-
TL431BQDBZR
Texas Instruments
-
AN431AN-ATRG1
Diodes Incorporated
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LM4040CYM3-2.5-TR
Microchip Technology
-
LM4040CYM3-4.1-TR
Microchip Technology
-
LM4040EIM3-2.5/NOPB
Texas Instruments
-
AZ431LBNTR-G1
Diodes Incorporated
-
LM4040D20IDBZR
Texas Instruments
-
LM4041DIM3-ADJ/NOPB
Texas Instruments
-
LM4040DIM3X-2.5/NOPB
Texas Instruments
-
LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
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