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STMicroelectronics TL1431ACCT
- Part No.:
- TL1431ACCT
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- 6-TSSOP, SC-88, SOT-363
- Datasheet:
-
TL1431ACCT.pdf
- Description:
- IC VREF SHNT ADJ 0.25% SOT323-6L
- Quantity:
- Payment:
- Shipping:
Inventory:3,230
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Product details
Overview
TL1431ACCT from STMicroelectronics is a precision adjustable shunt voltage reference IC with 0.25% initial voltage accuracy, 2.5 V reference input voltage, and guaranteed operation from −40 °C to +125 °C. It delivers 1–100 mA sink current capability, 0.2 Ω typical dynamic impedance, and supports output voltage programming from 2.5 V to 36 V using two external resistors - widely deployed in isolated flyback feedback loops and programmable power supply regulation.
For engineers reviewing the TL1431ACCT datasheet, TL1431ACCT pinout, TL1431ACCT application, or TL1431ACCT equivalent, this page provides verified electrical specifications, SOT323-6L package details, automotive-grade thermal performance data, and real-world use context for feedback path design, voltage monitoring, and precision biasing in industrial and automotive power systems.
Technical Context
The TL1431ACCT implements a bandgap-based shunt reference architecture with internal error amplifier and NPN pass transistor, enabling precise cathode-to-anode voltage regulation via external resistor divider feedback to the REF pin. Its low 0.25% initial tolerance and ±90 ppm/°C max temperature coefficient ensure stable reference voltage across wide ambient and load conditions.
It operates as a 3-terminal programmable zener: anode (A), cathode (K), and reference (REF) pins define its feedback-controlled shunt behavior. The device maintains regulation down to 0.5 mA minimum cathode current and exhibits <500 nA off-state leakage at 36 V, supporting high-impedance sensing and low-power standby modes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.493–2.507 V (0.25% initial accuracy at 25 °C, 10 mA cathode current) |
| Output Voltage Range | 2.5 V to 36 V (set externally via R1/R2 divider; enables flexible regulation without dedicated ICs) |
| Sink Current Range | 1–100 mA (supports direct drive of optocoupler LEDs or series-pass transistors in feedback paths) |
| Dynamic Impedance | 0.2–0.5 Ω (ensures minimal output voltage perturbation under fast load transients) |
| Temp. Coefficient | ±90 ppm/°C max (guaranteed over −40 °C to +125 °C; critical for automotive and industrial environments) |
| Voltage Deviation | ±7 mV over full temp range (−40 °C to +125 °C; enables tight closed-loop stability in SMPS designs) |
| Off-State Leakage | 180–500 nA at 36 V (minimizes quiescent current in always-on monitoring circuits) |
Pinout & Package
SOT323-6L plastic surface-mount package (3.2 mm × 1.35 mm × 0.95 mm), RoHS-compliant, ECOPACK®2 rated, optimized for high-density PCB layouts and automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Reference ground return | Low-impedance connection point for cathode current return path; tied to system GND or transformer secondary common in flyback designs |
| Cathode (Pin 2) | Regulated output node | Current-sinking terminal delivering precise voltage to optocoupler LED or base drive network; must be decoupled with ≥10 µF capacitor |
| REF (Pin 3) | Feedback input | High-impedance (2.5 µA typical) reference comparator input; connected to resistor divider midpoint for output voltage setting |
| NC (Pins 4–6) | No connect | Internally unconnected; left floating per datasheet - no routing or soldering required |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage | Programmable from 2.5 V to 36 V using only two external resistors - eliminates need for multiple fixed-voltage references |
| Automotive-grade temperature range | −40 °C to +125 °C operation with guaranteed specs - qualified per AEC-Q100 for engine control and ADAS power rails |
| Low dynamic impedance | 0.2 Ω typical ensures <1 mV output shift under 10 mA load step - critical for stable optocoupler bias in isolated converters |
| High ESD robustness | 2000 V HBM rating protects against handling damage during SMT assembly and field service |
| Low reference current | 1.5–3 µA input current minimizes divider power loss and improves efficiency in battery-backed or ultra-low-power applications |
Applications
| Isolated Flyback Power Supply | Programmable Bench Power Supply |
|---|---|
|
Use Scenario: Secondary-side voltage regulation in 5–48 V isolated DC-DC converters using optocoupler feedback. IC Role / Device Role / Timing Role: Shunt reference providing precise feedback voltage to optocoupler LED, closing the regulation loop across transformer barrier. Use Value: Enables ±1% output accuracy over line/load/temp with no primary-side controller compensation - reduces BOM count and layout complexity. |
Use Scenario: Digitally adjustable output voltage in lab-grade bench supplies with analog DAC interface. IC Role / Device Role / Timing Role: Precision voltage setpoint generator referenced to DAC output, driving series-pass transistor base via op-amp buffer. Use Value: Delivers 0.25% initial accuracy and <10 ppm/°C drift - ensures repeatable calibration and long-term stability without periodic recalibration. |
| Automotive Battery Monitor | Industrial Sensor Bias Reference |
|
Use Scenario: Monitoring 12 V vehicle battery voltage with over/under-voltage alarm thresholds. IC Role / Device Role / Timing Role: Stable 2.5 V reference for comparator inputs detecting battery state-of-charge deviations. Use Value: Maintains ±7 mV total deviation over −40 °C to +125 °C - prevents false alarms during cold cranking or under-hood thermal stress. |
Use Scenario: Providing excitation voltage to precision RTD or strain gauge bridges in factory automation sensors. IC Role / Device Role / Timing Role: Low-noise, low-drift reference source for Wheatstone bridge excitation, feeding instrumentation amplifier front-end. Use Value: 0.2 Ω dynamic impedance suppresses supply-induced ripple on bridge output - improves effective resolution by >12 bits in 24-bit ADC systems. |
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 accuracy, −40 °C to +125 °C, SO-8 package, 0.3 Ω dynamic impedance | Higher voltage deviation (±15 mV) and lower ESD rating (1500 V HBM); lacks AEC-Q100 qualification | Acceptable for non-automotive industrial supplies where cost is prioritized over precision and qualification |
| MAX6008AEUR+T | 0.2% initial accuracy, −40 °C to +125 °C, SOT23-3 package, 0.15 Ω dynamic impedance, but only 10 mA max sink current | Lower current capability limits use in optocoupler-driven feedback; no NC pins - smaller footprint but less layout flexibility | Preferred for ultra-low-power sensor nodes requiring sub-1 µA quiescent current and tighter initial tolerance |
Compared with TL431ACDR and MAX6008AEUR+T, TL1431ACCT uniquely balances automotive qualification, 100 mA sink capability, and 0.25% accuracy in a compact SOT323-6L package - making it optimal for space-constrained, safety-critical power feedback paths where both precision and robustness are mandatory.
Availability
TL1431ACCT is available at Aetrix Electronics and suitable for isolated power supplies, automotive battery monitors, programmable lab equipment, and industrial sensor signal chains requiring stable component supply with full traceability and lifecycle continuity.
Supply support for TL1431ACCT 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 components, and MEMS sensors for industrial, automotive, and consumer markets.
TL1431ACCT belongs to ST's precision analog reference product line, engineered specifically for high-reliability feedback control in isolated switching regulators and automotive-grade voltage monitoring systems.
FAQ
What is the minimum cathode current required for regulation in TL1431ACCT?
The TL1431ACCT requires a minimum cathode current of 0.5 mA to maintain regulation at 25 °C, increasing to 0.7 mA at +125 °C per datasheet Table 6. This ensures stable operation even in low-power standby modes when paired with high-value feedback resistors or low-current optocouplers.
Can TL1431ACCT replace TL431 in existing designs?
Yes - TL1431ACCT is pin-compatible with TL431 in SOT323-6L footprint and shares identical functional pinout (Anode, Cathode, REF). However, its 0.25% accuracy, lower dynamic impedance (0.2 Ω vs. 0.3 Ω), and AEC-Q100 qualification make it a direct upgrade for automotive and high-precision applications without circuit modification.
How does the SOT323-6L package affect thermal performance?
The SOT323-6L package has a junction-to-ambient thermal resistance (RthJA) of 221 °C/W. At 100 mA sink current and 36 V cathode-anode differential, power dissipation reaches 3.6 W - exceeding safe operating limits. Designers must limit VKA × Ik product to ≤0.5 W or add copper pour and thermal vias to maintain Tj < 125 °C.
What is the role of the NC pins in TL1431ACCT?
Pins 4–6 in the SOT323-6L package are internally unconnected (NC) and serve no electrical function. They must remain unconnected on the PCB - neither grounded nor routed - to avoid parasitic coupling or mechanical stress that could compromise package integrity or thermal performance.
TL1431ACCT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- 6-TSSOP, SC-88, SOT-363
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- 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:
- Surface Mount
- Supplier Device Package:
- SOT-323-6L
TL1431ACCT FAQ
1.How can I place an order for TL1431ACCT through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431ACCT 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 TL1431ACCT reliable?
The price and inventory of TL1431ACCT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431ACCT is usually 5 days.
3.What payment methods are accepted for TL1431ACCT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431ACCT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431ACCT?
TL1431ACCT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431ACCT 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 TL1431ACCT?
For technical support, including TL1431ACCT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431ACCT requirements.
6.How does Aetrix verify that TL1431ACCT is sourced from the original manufacturer or authorized distributors?
All TL1431ACCT 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 TL1431ACCT meets industry standards.
7.What is the process for return or replacement of TL1431ACCT?
All TL1431ACCT units undergo pre-shipment inspection (PSI). If there is an issue with TL1431ACCT, 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 TL1431ACCT part is unused and in its original packaging.
Return procedure for TL1431ACCT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431ACCT Tags
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