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Texas Instruments TL431CDRE4
- Part No.:
- TL431CDRE4
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431CDRE4.pdf
- Description:
- IC VREF SHUNT ADJ 2.2% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,313
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Product details
Overview
TL431CDRE4 from Texas Instruments is a precision programmable shunt voltage reference IC with 1% initial tolerance (A grade), 2.495 V nominal reference voltage, 0.2 Ω typical dynamic impedance, −40°C to 85°C operating temperature range (I grade), and sink-current capability from 1 mA to 100 mA. It functions as an adjustable voltage regulator or Zener diode replacement in feedback loops of isolated DC-DC converters.
For engineers reviewing the TL431CDRE4 datasheet, TL431CDRE4 pinout, TL431CDRE4 application, or TL431CDRE4 equivalent, key selection criteria include reference accuracy over temperature, cathode current range, dynamic impedance, thermal drift specification, and compatibility with SOT-23-3 PCB layout constraints.
Technical Context
The TL431CDRE4 implements a three-terminal adjustable shunt regulator architecture with an internal precision op-amp and NPN transistor output stage. Its REF pin senses voltage relative to ANODE, triggering cathode current conduction when input exceeds Vref × (1 + R1/R2).
It operates in continuous shunt regulation mode with active output circuitry enabling sharp turn-on characteristics. The device requires no external compensation for stability in standard feedback configurations and maintains regulation down to 0.4 mA minimum cathode current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Vref | 2.495 V nominal; sets precise threshold for feedback loop activation at 25°C |
| Initial Accuracy | ±1% (A grade); ensures output voltage error ≤ ±36 mV across full 2.5–36 V adjustment range |
| Temp Range | −40°C to +85°C (I grade); validated for industrial ambient conditions without derating |
| IKA Range | 1–100 mA cathode sink current; supports direct drive of optocoupler LEDs in flyback SMPS designs |
| Dynamic Impedance | 0.2 Ω typical; minimizes output voltage perturbation under load transients |
| VKA Max | 36 V maximum cathode-to-anode voltage; enables use in 24 V and 32 V bus applications |
| VI(dev) | 14 mV max deviation over full temperature range; translates to <0.06% tempco in closed-loop systems |
Pinout & Package
TL431CDRE4 is housed in a 3-pin SOT-23-3 package (2.90 mm × 1.30 mm body), with gull-wing leads and tape-and-reel packaging for automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (CATHODE) | Current sink output | Connects to high-side of feedback resistor divider or optocoupler anode; carries full regulated current |
| Pin 2 (REF) | Reference input | Senses voltage relative to ANODE; triggers regulation when VREF ≥ 2.495 V |
| Pin 3 (ANODE) | Common return | Typically tied to system ground or power supply return; serves as voltage reference point for REF pin |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output Voltage | 2.5 V to 36 V via two external resistors; eliminates need for multiple fixed-voltage references |
| Low Output Noise | Enables stable feedback in sensitive analog control loops without added filtering |
| Sharp Turn-On Characteristic | Reduces hysteresis in comparator-based monitoring circuits and improves transient response |
| Zener Replacement Capability | Replaces discrete Zener diodes with superior accuracy, lower tempco, and higher current handling |
| Thermal Stability | Specified VI(dev) ≤14 mV over −40°C to +85°C ensures consistent regulation in varying environments |
Applications
| Secondary Side Regulation | Zener Diode Replacement |
|---|---|
|
Use Scenario: Isolated flyback converter with optocoupler feedback across primary-secondary barrier. IC Role / Device Role / Timing Role: Shunt reference providing precise voltage threshold to drive optocoupler LED on secondary side. Use Value: Enables tight output voltage regulation (<±1%) without direct primary-side sensing, meeting safety isolation requirements. |
Use Scenario: On-board 5 V or 12 V rail stabilization in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Adjustable shunt regulator replacing 3.3 V/5 V/12 V Zener diodes in voltage-clamp or reference circuits. Use Value: Delivers 1% accuracy and 0.2 Ω impedance versus typical 5% Zener tolerance and >10 Ω impedance. |
| Voltage Monitoring | Comparator with Integrated Reference |
|
Use Scenario: Brown-out detection for microcontroller reset assertion during AC-DC adapter undervoltage events. IC Role / Device Role / Timing Role: Precision threshold detector comparing supply rail against internal 2.495 V reference. Use Value: Provides repeatable 4.75 V trip point (using R1/R2) with <10 mV hysteresis, eliminating external reference ICs. |
Use Scenario: Battery charge termination circuit comparing cell voltage to 4.2 V cutoff threshold. IC Role / Device Role / Timing Role: Self-contained comparator where REF pin acts as non-inverting input and CATHODE sinks comparator output current. Use Value: Reduces BOM count by integrating reference and output stage-no external op-amp or reference required. |
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 accuracy (B grade), same SOT-23-3 package and I-grade temp range | Required where tighter regulation tolerance is needed, e.g., precision ADC reference buffers | Select TL431ACDRE4 when system-level voltage error budget demands <±18 mV at 25°C |
| TL431IDR | Same electrical specs but SOIC-8 package (4.90 mm × 3.90 mm); no SOT-23-3 footprint compatibility | Suitable for through-hole or larger-layout designs where thermal mass or hand-soldering is preferred | Choose TL431IDR only if board space allows SOIC-8 and thermal dissipation >100 mW is required |
Compared with TL431CDRE4, TL431ACDRE4 improves reference accuracy by 0.5% at 25°C but shares identical temperature drift and dynamic impedance; TL431IDR offers identical performance in a larger SOIC-8 package, trading compactness for easier thermal management and manual assembly.
Availability
TL431CDRE4 is available at Aetrix Electronics and suitable for industrial power supplies, isolated DC-DC converters, and embedded voltage monitoring systems requiring stable component supply and long-term production continuity.
Supply support for TL431CDRE4 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 and embedded processing technologies, with leadership in precision analog ICs and power management solutions.
The TL431 family was designed as a drop-in upgrade to discrete Zener references, targeting cost-sensitive yet accuracy-critical applications in power conversion, voltage supervision, and feedback control systems.
FAQ
What is the reference voltage tolerance of TL431CDRE4 at 25°C?
The TL431CDRE4 has a ±1% initial reference voltage tolerance at 25°C (A grade), corresponding to a 2.495 V nominal value with a range of 2.470 V to 2.520 V. This is confirmed in Section 7.8 of the SLVS543P datasheet under Electrical Characteristics for TL431AC devices, which applies to TL431CDRE4 as its A-grade, I-temp variant.
Does TL431CDRE4 support operation above 85°C?
No, TL431CDRE4 is rated for −40°C to +85°C operation (I grade). It is not qualified for 125°C operation - that requires the Q-grade variant (e.g., TL431BQDBVR). Exceeding 85°C ambient may cause VI(dev) to exceed 14 mV and increase risk of thermal runaway under high cathode current.
What is the minimum cathode current required for regulation in TL431CDRE4?
The TL431CDRE4 requires a minimum cathode current (Imin) of 0.4 mA to maintain regulation, as specified in Sections 7.8 and 7.9 of the datasheet. Below this level, the device exits active regulation and behaves as an open circuit between CATHODE and ANODE.
Can TL431CDRE4 replace a standard 3.3 V Zener diode directly?
Yes, TL431CDRE4 can directly replace a 3.3 V Zener diode using R1 = 1.0 kΩ and R2 = 3.9 kΩ to set VOUT = 3.3 V. Its 0.2 Ω dynamic impedance, 1% accuracy, and 14 mV tempco significantly outperform typical 5% tolerance, >10 Ω impedance Zeners - no circuit redesign is needed beyond resistor substitution.
Is TL431CDRE4 pin-compatible with TL431ACDRE4?
Yes, TL431CDRE4 and TL431ACDRE4 share identical SOT-23-3 pinout (CATHODE–REF–ANODE), same package dimensions, and compatible thermal characteristics. They differ only in initial accuracy (1% vs. 0.5%), making TL431ACDRE4 a direct accuracy-upgrade option without layout changes.
TL431CDRE4 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:
- ±2.2%
- 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:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TL431CDRE4 FAQ
1.How can I place an order for TL431CDRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431CDRE4 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 TL431CDRE4 reliable?
The price and inventory of TL431CDRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431CDRE4 is usually 5 days.
3.What payment methods are accepted for TL431CDRE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431CDRE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431CDRE4?
TL431CDRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431CDRE4 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 TL431CDRE4?
For technical support, including TL431CDRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431CDRE4 requirements.
6.How does Aetrix verify that TL431CDRE4 is sourced from the original manufacturer or authorized distributors?
All TL431CDRE4 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 TL431CDRE4 meets industry standards.
7.What is the process for return or replacement of TL431CDRE4?
All TL431CDRE4 units undergo pre-shipment inspection (PSI). If there is an issue with TL431CDRE4, 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 TL431CDRE4 part is unused and in its original packaging.
Return procedure for TL431CDRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431CDRE4 Tags
-
TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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AN431AN-ATRG1
Diodes Incorporated
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LM4040CYM3-2.5-TR
Microchip Technology
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LM4040CYM3-4.1-TR
Microchip Technology
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LM4040EIM3-2.5/NOPB
Texas Instruments
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AZ431LBNTR-G1
Diodes Incorporated
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LM4040D20IDBZR
Texas Instruments
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LM4041DIM3-ADJ/NOPB
Texas Instruments
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LM4040DIM3X-2.5/NOPB
Texas Instruments
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LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
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