My Inquiry
My Account
STMicroelectronics TL1431IDT
- Part No.:
- TL1431IDT
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL1431IDT.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:32,303
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
TL1431IDT from STMicroelectronics is an adjustable shunt voltage reference IC with 0.4% initial voltage precision, guaranteed operation from −40 °C to +105 °C, 2.5 V to 36 V programmable output via two external resistors, and 1–100 mA sink current capability. It serves as a precision voltage setpoint in feedback loops of isolated DC-DC converters, linear regulators, and overvoltage protection circuits.
For engineers reviewing the TL1431IDT datasheet, TL1431IDT pinout, TL1431IDT application, or TL1431IDT equivalent, this page delivers verified electrical parameters, SO-8 package terminal mapping, automotive-grade thermal stability data, and real-world use cases in power supply regulation and voltage monitoring systems.
Technical Context
The TL1431IDT implements a bandgap-based reference core with internal error amplifier and NPN pass transistor, configured as a 3-terminal shunt regulator. Its reference input (REF) senses voltage at the cathode–anode junction through external resistor dividers, enabling precise closed-loop control independent of input voltage variation.
It operates across a wide cathode current range (1–100 mA) with typical dynamic impedance of 0.22 Ω and maintains ±7 mV reference deviation over its full −40 °C to +105 °C operating range - meeting industrial and extended-temperature system requirements without external compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V (typical), ±0.4% initial accuracy - sets precise feedback threshold for power supply regulation |
| Output Voltage Range | 2.5 V to 36 V - programmable via external R1/R2 divider, enabling flexible voltage monitoring and regulation |
| Sink Current Range | 1–100 mA - supports direct drive of optocoupler LEDs or error amplifier inputs in isolated topologies |
| Dynamic Impedance | 0.22 Ω (typical) - ensures stable regulation under fast load transients in feedback paths |
| Temp. Stability | ±7 mV max deviation from −40 °C to +105 °C - enables reliable operation in automotive engine-control modules |
| Reference Input Current | 1.5–3.0 µA - low bias current minimizes divider network power loss and voltage error |
| Min. Cathode Current | 0.5 mA - defines lowest usable current for stable regulation, critical for low-power standby modes |
Pinout & Package
TL1431IDT is supplied in SO-8 (batwing plastic micropackage), compliant with ECOPACK® environmental standards. The package features gull-wing leads, 1.27 mm pitch, and thermal resistance RthJA = 85 °C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Anode) | Anode connection | Common return node for cathode current; tied to system ground or negative rail in shunt configuration |
| 2 (Cathode) | Cathode output | Sinks regulated current; connects to feedback node or optocoupler LED anode in isolated PSUs |
| 3 (Ref) | Reference input | High-impedance sense input; connected to resistor divider midpoint to set output voltage |
| 4–8 (NC) | No-connect terminals | Internally unconnected; left floating per datasheet - no routing or grounding required |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage | 2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-reference SKUs |
| Automotive temperature range | −40 °C to +105 °C operation - qualified for under-hood and body-control module applications |
| Low dynamic impedance | 0.22 Ω typical - maintains tight regulation during rapid load changes in switching converter feedback |
| High sink current capability | 100 mA max cathode current - drives standard optocouplers (e.g., PC817) without external buffer |
| Low reference input current | 2.5 µA typical - reduces resistor-divider power dissipation and thermal drift in precision designs |
Applications
| Isolated Flyback Converter Feedback | Overvoltage Protection Circuit |
|---|---|
Use Scenario: Regulates output voltage in 12 V/5 V isolated flyback supplies using TL431-compatible optocoupler interface. IC Role / Device Role / Timing Role: Shunt reference provides precise 2.5 V threshold to control optocoupler LED current, closing feedback loop across isolation barrier. Use Value: Enables ±1% output regulation over line/load/temperature with minimal external components and no secondary-side controller. | Use Scenario: Monitors 24 V rail in industrial PLC I/O modules and triggers shutdown if voltage exceeds 27 V. IC Role / Device Role / Timing Role: Configured as comparator with hysteresis; REF pin biased to 2.5 V, cathode drives MOSFET gate via pull-up when overvoltage detected. Use Value: Provides sub-10 ms response time and eliminates need for dedicated voltage supervisor ICs. |
| Programmable Linear Regulator | Current Sink for LED Biasing |
Use Scenario: Sets output of LM317-based lab bench supply to user-selectable 3.3–15 V range via front-panel potentiometer. IC Role / Device Role / Timing Role: Replaces internal 1.25 V reference with externally adjustable 2.5 V baseline, extending LM317 output range and resolution. Use Value: Achieves 0.1% setting accuracy and improves load regulation by reducing reference dependency on ADJ pin current. | Use Scenario: Sinks constant 20 mA from high-brightness white LED string in automotive interior lighting. IC Role / Device Role / Timing Role: Acts as precision current sink: REF pin tied to fixed resistor, cathode connected to LED cathode, anode grounded. Use Value: Delivers ±3% current accuracy over −40 °C to +85 °C without sense resistor or op-amp, reducing BOM count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDT | 0.25% initial accuracy, −40 °C to +85 °C rating, same SO-8 footprint | Limited to commercial/industrial ambient; insufficient for extended-temperature automotive use | Select when tighter initial tolerance is prioritized over high-temp operation |
| TL1431CDT | 0.4% accuracy, −20 °C to +70 °C rating, identical electrical specs otherwise | Not qualified for automotive or industrial environments requiring >+70 °C operation | Choose for cost-sensitive consumer applications where ambient stays within 0–60 °C |
Compared with TL431ACDT and TL1431CDT, TL1431IDT uniquely combines 0.4% precision with −40 °C to +105 °C operation in SO-8, making it the only drop-in option for automotive power management and industrial control systems requiring extended thermal reliability.
Availability
TL1431IDT is available at Aetrix Electronics and suitable for isolated DC-DC converters, overvoltage protection circuits, and programmable linear regulators requiring stable component supply across automotive, industrial, and telecom power applications.
Supply support for TL1431IDT 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 devices, analog ICs, and MEMS sensors for industrial, automotive, and consumer markets.
The TL1431 product line delivers precision shunt references optimized for feedback control in power conversion systems, with variants engineered specifically for automotive AEC-Q100 compliance and extended-temperature industrial deployment.
FAQ
What is the minimum cathode current required for regulation in TL1431IDT?
The TL1431IDT requires a minimum cathode current of 0.5 mA to maintain regulation, as specified in Table 4 of the datasheet under "Imin Minimum cathode current for regulation." This value holds across its full −40 °C to +105 °C operating range and ensures stable reference behavior even in ultra-low-power standby modes of power supplies.
Can TL1431IDT replace TL431 in existing designs?
Yes - TL1431IDT is pin-compatible and electrically equivalent to TL431 in SO-8 packages, with identical pinout (Anode, Cathode, Ref) and matching 2.5 V reference, 1–100 mA sink capability, and 0.22 Ω dynamic impedance. Its −40 °C to +105 °C rating further extends operational margin beyond standard TL431 variants.
Does TL1431IDT require external capacitors for stability?
No external capacitor is required for basic shunt operation, but a 10 nF ceramic capacitor between REF and Anode is recommended when driving capacitive loads (>100 pF) or long PCB traces to prevent oscillation. Figure 20 in the datasheet confirms stable operation up to 100 nF with proper layout and decoupling.
How does the 0.4% voltage precision impact system-level accuracy?
The 0.4% initial reference voltage tolerance (±10 mV around 2.5 V) directly limits total output voltage error in feedback-based power supplies. When combined with resistor divider tolerance (e.g., 1% R1/R2), overall output accuracy remains within ±1.5%, sufficient for most industrial and automotive DC-DC applications without trimming.
TL1431IDT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- 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:
- ±0.4%
- Temperature Coefficient:
- 100ppm/°C
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TL1431IDT FAQ
1.How can I place an order for TL1431IDT through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431IDT 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 TL1431IDT reliable?
The price and inventory of TL1431IDT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431IDT is usually 5 days.
3.What payment methods are accepted for TL1431IDT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431IDT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431IDT?
TL1431IDT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431IDT 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 TL1431IDT?
For technical support, including TL1431IDT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431IDT requirements.
6.How does Aetrix verify that TL1431IDT is sourced from the original manufacturer or authorized distributors?
All TL1431IDT 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 TL1431IDT meets industry standards.
7.What is the process for return or replacement of TL1431IDT?
All TL1431IDT units undergo pre-shipment inspection (PSI). If there is an issue with TL1431IDT, 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 TL1431IDT part is unused and in its original packaging.
Return procedure for TL1431IDT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431IDT Tags
-
TL431AIDBZR
Texas Instruments
-
TL431BQDBZR
Texas Instruments
-
AN431AN-ATRG1
Diodes Incorporated
-
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
Tech Hub
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
