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Texas Instruments TL431ACDR
- Part No.:
- TL431ACDR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431ACDR.pdf
- Description:
- IC VREF SHUNT ADJ 1% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:14,184
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Product details
Overview
TL431ACDR from Texas Instruments is a precision programmable shunt voltage reference IC with 1% initial tolerance at 25°C, adjustable output from 2.47V to 36V, and operation across −40°C to 85°C. It delivers 0.2Ω typical dynamic impedance, 1–100mA sink-current capability, and low 6mV temperature drift (I-grade), widely used in feedback loops of AC/DC adapters and industrial power supplies.
For engineers reviewing the TL431ACDR datasheet, TL431ACDR pinout, TL431ACDR application, or TL431ACDR equivalent, this page provides verified electrical specs, SOT-23-3 package details, thermal performance data, stability boundary conditions, and validated alternative parts for power supply regulation design.
Technical Context
The TL431ACDR implements an internal error amplifier and NPN transistor output stage configured as a three-terminal adjustable shunt regulator. Its REF pin senses voltage relative to ANODE, triggering cathode current modulation to maintain precise Vref = 2.495V ±25mV at 10mA.
It operates in closed-loop feedback configurations where external resistor dividers set output voltage, and its sharp turn-on characteristic enables stable regulation without external compensation in most switching and linear supply topologies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V ±25 mV at 25°C - sets accuracy baseline for feedback loop calibration |
| Initial Tolerance | ±1% (A grade) - ensures ≤25 mV deviation at room temperature for tight regulation |
| Temp Range | −40°C to +85°C (I grade) - supports industrial ambient conditions without derating |
| Dynamic Impedance | 0.2 Ω typical - minimizes output voltage variation under load transients |
| Sink Current Range | 1 mA to 100 mA - enables direct drive of optocoupler LEDs or error amplifier inputs |
| Temp Drift (VI(dev)) | 14 mV max over full range - guarantees <0.017%/°C effective TC for stable long-term output |
| Off-State Cathode Leakage | ≤0.5 µA at 36 V - prevents unintended conduction in high-impedance bias networks |
Pinout & Package
TL431ACDR is supplied in the SOT-23-3 (DBZ) package, measuring 2.90 mm × 1.30 mm, with gull-wing leads and exposed substrate connected internally to ANODE.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1: Cathode | Shunt current output node | Connects to primary-side feedback path; sinks regulated current into power rail or optocoupler anode |
| Pin 2: Reference | High-impedance voltage sense input | Monitors divided output voltage; triggers regulation when ≥2.495 V relative to ANODE |
| Pin 3: Anode | Common return/reference ground | Must be tied to system ground or power rail common point; substrate connection requires grounding or open-circuit |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output Range | 2.47 V to 36 V via two-resistor divider - eliminates need for multiple fixed-reference parts |
| Low Dynamic Impedance | 0.2 Ω typical - maintains regulation during fast load steps without external capacitor |
| Wide Operating Temperature | −40°C to +85°C - qualified for industrial power conversion environments |
| Low Reference Input Current | 2–4 µA - reduces divider power loss and improves high-voltage sensing accuracy |
| Stability Without Compensation | Validated stable with ≤100 nF capacitive loads - simplifies feedback network design |
Applications
| Rack Server Power | Industrial AC/DC Converter |
|---|---|
Use Scenario: Secondary-side voltage regulation in 1U server PSUs with digital PMBus control. IC Role / Device Role / Timing Role: Shunt reference in optocoupler-coupled feedback loop, setting 12 V and 3.3 V outputs. Use Value: ±1% tolerance and 14 mV temp drift ensure output stays within ±2% over full operating range without recalibration. |
Use Scenario: Isolated output regulation in DIN-rail mounted 24 V/10 A industrial power supplies. IC Role / Device Role / Timing Role: Precision reference for TL431-based feedback network driving PC817 optocoupler. Use Value: 0.2 Ω dynamic impedance suppresses ripple-induced output variation under 50% load step changes. |
| AC Inverter Drive | Notebook PC Adapter |
Use Scenario: DC bus voltage monitoring and overvoltage protection in 3-phase motor drives. IC Role / Device Role / Timing Role: Programmable threshold detector feeding comparator input for fault shutdown logic. Use Value: Adjustable 2.47–36 V range allows single BOM part to cover 400 V, 690 V, and 1 kV DC bus variants. |
Use Scenario: Constant-voltage regulation in 19.5 V/3.34 A laptop adapters with QR flyback topology. IC Role / Device Role / Timing Role: Primary-side referenced shunt regulator controlling UCC28704 controller via optocoupler. Use Value: Low 4 µA max Iref minimizes divider resistor heat and enables high-resistance scaling for 19.5 V setpoint. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431AIDR | SOIC-8 package; same A-grade tolerance and I-temp range but higher RθJA (97°C/W vs 206°C/W) | Better thermal margin in high-power PCB layouts; requires larger footprint and reflow profile adjustment | Choose for designs needing higher power dissipation headroom or legacy SOIC compatibility |
| TLVH431AQDBVR | Lower 1.24 V reference; 1% tolerance; Q-temp (−40°C to 125°C); SOT-23-3 | Enables sub-2 V output regulation; wider temp range suits automotive under-hood use | Choose when regulating ≤2 V rails or requiring extended temperature qualification |
Compared with TL431ACDR, TL431AIDR offers superior thermal performance in board-level power dissipation scenarios, while TLVH431AQDBVR enables lower-voltage regulation and extended temperature operation-neither is pin-compatible, but both serve adjacent functional roles in feedback design.
Availability
TL431ACDR is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and notebook PC adapter designs requiring stable component supply, consistent parametric performance, and long-term production continuity.
Supply support for TL431ACDR 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 leader specializing in analog, embedded processing, and power management technologies, with decades of heritage in precision reference design.
The TL431 family was engineered for high-accuracy, low-drift voltage regulation in isolated power supply feedback paths-targeting cost-sensitive yet thermally demanding industrial and computing applications.
FAQ
What is the reference voltage tolerance of TL431ACDR at 25°C?
The TL431ACDR has a guaranteed initial reference voltage tolerance of ±1% at 25°C, corresponding to a 2.470 V to 2.520 V range per the TL431AC datasheet section 6.8. This A-grade specification ensures predictable feedback loop accuracy without post-manufacturing trimming, and is validated across production lots at Texas Instruments test facilities.
Does TL431ACDR support operation at −40°C?
Yes, TL431ACDR is rated for operation from −40°C to +85°C (I-grade). Its VI(dev) parameter is specified at 14 mV maximum over this full range, confirming stable regulation in cold industrial environments. The device remains fully functional with no derating required below 0°C, unlike C-grade variants limited to 0°C minimum.
What package type is used for TL431ACDR?
TL431ACDR uses the SOT-23-3 (DBZ) package, a 3-pin surface-mount outline measuring 2.90 mm × 1.30 mm. Pin 1 is Cathode, Pin 2 is REF, and Pin 3 is ANODE-with the substrate electrically tied to ANODE and requiring connection to ground or left open per TI's DBZ mechanical drawing.
Can TL431ACDR replace a Zener diode in feedback circuits?
Yes, TL431ACDR is explicitly designed as a superior replacement for Zener diodes in voltage regulation feedback paths. Its 0.2 Ω dynamic impedance, sharp turn-on, and adjustable 2.47–36 V range provide tighter regulation, lower temperature drift, and greater design flexibility than discrete Zeners-especially in optocoupler-coupled SMPS designs.
What is the minimum cathode current needed for TL431ACDR regulation?
The TL431ACDR requires a minimum cathode current (Imin) of 0.4 mA to maintain regulation, per section 6.8 of the datasheet. This low threshold enables reliable startup and light-load operation in high-efficiency adapters, and allows use with large-value feedback resistors to minimize standby power consumption.
TL431ACDR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- 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):
- 2.495V
- 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:
- 600 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TL431ACDR FAQ
1.How can I place an order for TL431ACDR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431ACDR 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 TL431ACDR reliable?
The price and inventory of TL431ACDR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431ACDR is usually 5 days.
3.What payment methods are accepted for TL431ACDR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431ACDR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431ACDR?
TL431ACDR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431ACDR 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 TL431ACDR?
For technical support, including TL431ACDR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431ACDR requirements.
6.How does Aetrix verify that TL431ACDR is sourced from the original manufacturer or authorized distributors?
All TL431ACDR 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 TL431ACDR meets industry standards.
7.What is the process for return or replacement of TL431ACDR?
All TL431ACDR units undergo pre-shipment inspection (PSI). If there is an issue with TL431ACDR, 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 TL431ACDR part is unused and in its original packaging.
Return procedure for TL431ACDR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431ACDR Tags
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TL431AIDBZR
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LM4040DIM3X-2.5/NOPB
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AZ431LANTR-G1
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