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Texas Instruments TL431AIDRE4
- Part No.:
- TL431AIDRE4
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431AIDRE4.pdf
- Description:
- IC VREF SHUNT ADJ 1% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,116
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Product details
Overview
TL431AIDRE4 from Texas Instruments is a precision programmable shunt voltage reference IC with 1% initial tolerance at 25°C, adjustable output from 2.495 V to 36 V via two external resistors, 0.2 Ω typical dynamic impedance, −40°C to 85°C operating range (I-grade), and sink-current capability from 1 mA to 100 mA - used in secondary-side regulation of flyback SMPSs.
For engineers reviewing the TL431AIDRE4 datasheet, TL431AIDRE4 pinout, TL431AIDRE4 application, or TL431AIDRE4 equivalent, this page delivers verified electrical specs, SOT-23-3 pin mapping, thermal performance data, real-world use cases in power supply feedback loops, and validated alternative parts for design flexibility and supply continuity.
Technical Context
The TL431AIDRE4 implements a three-terminal adjustable shunt regulator architecture with an internal 2.495 V reference and high-gain error amplifier driving an NPN output stage. Its sharp turn-on characteristic and low output impedance enable Zener diode replacement in closed-loop feedback paths.
It operates as a voltage-controlled current sink: when the REF pin voltage exceeds 2.495 V, cathode current increases to maintain regulation; minimum cathode current for stable regulation is 0.4 mA, and off-state cathode leakage remains ≤0.5 µA at 36 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VREF tolerance | ±1% at 25°C - ensures tight initial setpoint accuracy for feedback networks without trimming |
| Adjustable range | 2.495 V to 36 V - supports wide-output DC-DC converters using only two external resistors |
| Dynamic impedance | 0.2 Ω typical - minimizes output voltage variation under load transients in regulation loops |
| Operating temperature | −40°C to +85°C - qualified for industrial ambient conditions without derating |
| Cathode current | 1 mA to 100 mA sink capability - accommodates diverse feedback divider currents and optocoupler drive requirements |
| Reference input current | 2–4 µA - enables high-impedance resistor networks to minimize power loss in battery-sensitive designs |
| Temp drift (VI(dev)) | 14 mV max over full range - maintains <0.05% output stability across industrial temperature span |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm body), surface-mount, lead-free, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CATHODE) | Current sink output | Connects to SMPS transformer secondary or feedback node; sinks current to regulate voltage |
| 2 (REF) | Reference input | High-impedance threshold input; voltage >2.495 V triggers regulation; sets output via R1/R2 divider |
| 3 (ANODE) | Common return | Typically tied to system ground or power rail common; defines reference potential for REF and CATHODE |
Key Features
| Feature | Design Value |
|---|---|
| Sharp turn-on characteristic | Enables clean switching between regulation and cutoff states - critical for stable optocoupler-based feedback in isolated supplies |
| Low output noise | Reduces ripple injection into control loops - improves transient response and EMI performance in sensitive analog feedback paths |
| Zener diode replacement capability | Eliminates need for discrete Zener + series resistor - simplifies BOM, improves accuracy, and lowers temperature coefficient vs. standard Zeners |
| Stable operation down to 0.4 mA IK(min) | Allows ultra-low-power feedback networks - extends battery life in always-on monitoring circuits and energy-harvesting systems |
Applications
| Switch-Mode Power Supply Feedback | Voltage Monitoring & Protection |
|---|---|
Use Scenario: Secondary-side voltage sensing in isolated flyback converters with optocoupler-coupled feedback loop. IC Role / Device Role / Timing Role: Adjustable shunt reference providing precise 2.495 V threshold to control optocoupler LED current and thus primary-side PWM duty cycle. Use Value: Enables ±1% output regulation across line/load/temperature without secondary-side LDO - reduces component count and improves efficiency. | Use Scenario: Overvoltage detection circuit triggering shutdown when bus voltage exceeds safe limit. IC Role / Device Role / Timing Role: Precision voltage comparator with integrated reference - REF pin compares monitored voltage against internal 2.495 V, CATHODE sinks current to activate protection transistor. Use Value: Eliminates external reference IC and resistor divider - achieves <1% trip-point accuracy with single-component solution. |
| Adjustable Linear Regulator Reference | Programmable Current Sink |
Use Scenario: Setting output voltage of LM317-type adjustable linear regulators via external resistor network. IC Role / Device Role / Timing Role: High-stability reference replacing fixed 1.25 V bandgap - REF pin replaces ADJ input, enabling higher output voltages and tighter tolerance. Use Value: Improves output accuracy from ±2% to ±1% and reduces tempco drift by 3× versus standard LM317 internal reference. | Use Scenario: Constant-current source for LED biasing or sensor excitation where current must track reference voltage. IC Role / Device Role / Timing Role: Shunt regulator configured with REF tied to fixed voltage and CATHODE sinking current proportional to external sense resistor. Use Value: Delivers 1% accurate current regulation independent of supply voltage variations - ideal for precision analog front-ends. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDRE4 | 0.5% initial tolerance (B-grade), same SOT-23-3 package and electrical specs | Better accuracy required for high-end instrumentation or metrology-grade power supplies | Select when tighter initial setpoint is mandatory and cost premium is acceptable |
| TL431AILP | TO-92 through-hole package, identical I-grade specs, 1% tolerance, −40°C to 85°C | Prototyping, legacy board upgrades, or manual assembly where SMT is impractical | Choose for breadboarding, repair, or mixed-technology PCBs requiring through-hole compatibility |
Compared with TL431AIDRE4, TL431ACDRE4 offers higher accuracy but same thermal and dynamic performance, while TL431AILP provides identical electrical behavior in a through-hole form factor - enabling drop-in functional replacement where package constraints allow.
Availability
TL431AIDRE4 is available at Aetrix Electronics and suitable for industrial power supplies, isolated DC-DC converters, and voltage-monitoring circuits requiring stable component supply with guaranteed long-term sourcing.
Supply support for TL431AIDRE4 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
Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and power management technologies with over 90 years of innovation in precision analog ICs.
The TL431 product line was designed specifically for high-accuracy, low-drift voltage referencing in power supply feedback, battery management, and industrial monitoring systems - emphasizing stability, simplicity, and broad temperature operation.
FAQ
What is the reference voltage tolerance of TL431AIDRE4 at 25°C?
The TL431AIDRE4 has a reference voltage tolerance of ±1% at 25°C, corresponding to a nominal VREF of 2.495 V with a min/max range of 2.470 V to 2.520 V. This A-grade specification is confirmed in Section 7.8 of the TI SLVS543P datasheet and applies across all operating conditions within its recommended cathode current and voltage ranges. TL431AIDRE4 maintains this accuracy without external calibration.
Can TL431AIDRE4 replace a Zener diode in a power supply design?
Yes, TL431AIDRE4 is explicitly designed as a precision Zener diode replacement. Its sharp turn-on characteristic, 0.2 Ω dynamic impedance, and 1% initial tolerance provide superior regulation accuracy and stability compared to standard Zeners. In practice, TL431AIDRE4 replaces both the Zener and its series current-limiting resistor - reducing component count and improving temperature drift performance in feedback networks of flyback and forward converters.
What is the minimum cathode current required for regulation in TL431AIDRE4?
The minimum cathode current required for stable regulation in TL431AIDRE4 is 0.4 mA, as specified in Sections 7.8 and 7.9 of the TI datasheet under "Imin". This value holds across the full −40°C to +85°C operating range and enables low-power feedback configurations. Operating below this threshold may result in loss of regulation or increased output impedance, particularly at temperature extremes.
Does TL431AIDRE4 support operation above 85°C ambient temperature?
No, TL431AIDRE4 is rated for operation from −40°C to +85°C ambient (I-grade). It is not qualified for 125°C operation - that specification applies only to Q-grade variants like TL431BQDBZR. Exceeding +85°C ambient risks parametric shift beyond datasheet limits, reduced reliability, and potential thermal shutdown. For high-temp applications, TL431AIDRE4 must be thermally managed or replaced with a Q-grade part.
What package type does TL431AIDRE4 use, and is it RoHS-compliant?
TL431AIDRE4 uses the SOT-23-3 surface-mount package (2.90 mm × 1.30 mm body) with lead-free, RoHS-compliant terminations. The "E4" suffix in the part number denotes TI's green packaging standard. Pin configuration is CATHODE–REF–ANODE (left-to-right, top view), matching JEDEC MO-178AB mechanical specifications and compatible with standard SMT reflow profiles.
TL431AIDRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- 700 µA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TL431AIDRE4 FAQ
1.How can I place an order for TL431AIDRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431AIDRE4 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 TL431AIDRE4 reliable?
The price and inventory of TL431AIDRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431AIDRE4 is usually 5 days.
3.What payment methods are accepted for TL431AIDRE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431AIDRE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431AIDRE4?
TL431AIDRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431AIDRE4 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 TL431AIDRE4?
For technical support, including TL431AIDRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431AIDRE4 requirements.
6.How does Aetrix verify that TL431AIDRE4 is sourced from the original manufacturer or authorized distributors?
All TL431AIDRE4 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 TL431AIDRE4 meets industry standards.
7.What is the process for return or replacement of TL431AIDRE4?
All TL431AIDRE4 units undergo pre-shipment inspection (PSI). If there is an issue with TL431AIDRE4, 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 TL431AIDRE4 part is unused and in its original packaging.
Return procedure for TL431AIDRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431AIDRE4 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
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