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Texas Instruments TL431CPW
- Part No.:
- TL431CPW
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
TL431CPW.pdf
- Description:
- IC VREF SHUNT ADJ 2.2% 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,122
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Product details
Overview
TL431CPW from Texas Instruments is a precision programmable shunt voltage reference IC with 0.5% initial tolerance (B grade), 2.495 V nominal reference voltage, adjustable output from 2.5 V to 36 V, 0.2 Ω typical dynamic impedance, and operation across −40°C to 85°C (I-grade thermal range). It serves as a Zener diode replacement in secondary-side regulation of flyback SMPSs.
For engineers reviewing the TL431CPW datasheet, TL431CPW pinout, TL431CPW application, or TL431CPW equivalent, this page delivers verified electrical specs, TSSOP-8 package terminal mapping, real-world use cases in power supply feedback loops, and validated alternative parts for design flexibility and supply continuity.
Technical Context
The TL431CPW implements a three-terminal adjustable shunt regulator architecture with an internal precision reference and error amplifier driving an NPN output stage. Its sharp turn-on characteristic and low 0.2 Ω dynamic impedance enable stable closed-loop regulation when paired with external resistive dividers.
It operates as a sink device: cathode current (IKA) flows from external supply into the cathode pin, through the internal circuitry, and out the anode pin to ground or return path; reference voltage (Vref = 2.495 V) is sensed at the REF pin relative to anode potential.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Vref | 2.495 V nominal; sets precise threshold for feedback loop-enables accurate output voltage setting via R1/R2 divider |
| Initial tolerance | ±0.5% at 25°C (B grade); ensures tight output voltage accuracy without post-manufacturing trimming |
| Adjustable range | 2.5 V to 36 V; supports wide variety of regulated outputs using only two external resistors |
| Dynamic impedance | 0.2 Ω typical; minimizes output voltage variation under load transients in feedback networks |
| Operating temperature | −40°C to +85°C (I-grade); qualified for industrial environments including motor drives and PLCs |
| Cathode current | 1 mA to 100 mA sink capability; provides sufficient drive for optocoupler LEDs in isolated SMPS designs |
| Reference input current | 2–4 µA; ultra-low bias current reduces divider resistor power loss and improves high-impedance sensing |
Pinout & Package
TSSOP-8 (PW) package: 3.0 mm × 4.4 mm body, 0.65 mm pitch, exposed thermal pad (connected to ANODE internally).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CATHODE) | Sink current input | Primary current path-connects to SMPS transformer secondary or regulated rail; must handle up to 100 mA |
| 2 (NC) | No internal connection | Unused pin-leave unconnected; no routing or grounding required |
| 3 (NC) | No internal connection | Unused pin-leave unconnected; no routing or grounding required |
| 4 (REF) | Reference voltage sense | High-impedance input sensing 2.495 V threshold-ties to voltage divider midpoint in feedback network |
| 5 (ANODE) | Common return path | Internal connection to substrate and thermal pad-must be connected to system ground or return node |
| 6 (NC) | No internal connection | Unused pin-leave unconnected; no routing or grounding required |
| 7 (NC) | No internal connection | Unused pin-leave unconnected; no routing or grounding required |
| 8 (NC) | No internal connection | Unused pin-leave unconnected; no routing or grounding required |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% reference tolerance (B grade) | Enables ±1% system-level output voltage accuracy in well-designed feedback loops without calibration |
| 0.2 Ω dynamic impedance | Reduces sensitivity to cathode current ripple-critical for stable optocoupler-driven isolation in flyback converters |
| 2–4 µA reference input current | Allows use of high-value feedback resistors (e.g., 1 MΩ/2 MΩ), minimizing standby power in energy-sensitive applications |
| −40°C to +85°C operation | Supports deployment in industrial control cabinets, outdoor power supplies, and automotive auxiliary systems |
| Zener-replacement functionality | Eliminates need for multiple discrete Zener voltages-single part covers 2.5–36 V range with superior stability |
Applications
| Secondary-Side Regulation (Flyback SMPS) | Zener Diode Replacement |
|---|---|
Use Scenario: Isolated DC-DC converter where primary-side controller lacks direct output sensing. IC Role / Device Role / Timing Role: Shunt reference providing precise feedback voltage to optocoupler LED, closing regulation loop across isolation barrier. Use Value: Enables ±1% output voltage accuracy over line/load/temperature-unachievable with standard Zeners due to drift and impedance limitations. |
Use Scenario: Voltage clamping or threshold detection in analog monitoring circuits. IC Role / Device Role / Timing Role: Precision shunt element replacing discrete Zener diodes in voltage reference, overvoltage protection, or comparator hysteresis networks. Use Value: Delivers 0.5% initial accuracy and <15 mV full-range drift-reducing calibration burden and improving long-term reliability vs. 5% tolerance Zeners. |
| Voltage Monitoring System | Adjustable Power Supply Reference |
Use Scenario: Real-time rail supervision in telecom or server power modules. IC Role / Device Role / Timing Role: Reference input to comparator detecting undervoltage/overvoltage events on 3.3 V, 5 V, or 12 V rails. Use Value: Ultra-low 2–4 µA reference current avoids loading monitored rail-preserving measurement integrity in high-impedance sensing nodes. |
Use Scenario: Lab-grade bench power supply with user-adjustable output. IC Role / Device Role / Timing Role: Programmable reference core enabling continuous 1.25–30 V output via front-panel potentiometer and feedback divider. Use Value: 0.2 Ω dynamic impedance maintains regulation stability even during rapid load steps-critical for test equipment performance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431IPW | Same TSSOP-8 package and B-grade accuracy, but rated for −40°C to +85°C (I-grade) instead of C-grade (0°C to 70°C)-TL431CPW is C-grade per TI nomenclature | TL431IPW supports wider temperature range; TL431CPW optimized for cost-sensitive commercial applications within 0°C–70°C ambient | Select TL431CPW for cost-driven consumer electronics; choose TL431IPW for industrial deployments requiring extended temperature coverage. |
| TLVH431QDBVR | Lower 1.24 V reference voltage, 1% initial tolerance, SOT-23-5 package, 30 V max cathode voltage-different pinout and voltage range | Not drop-in compatible; requires PCB redesign and recalculated feedback divider; suited for low-voltage (<3 V) systems where 2.5 V reference is excessive | Use TLVH431QDBVR only when 1.24 V reference and lower operating voltage are mandatory; TL431CPW remains optimal for 2.5–36 V range with highest accuracy. |
Compared with TL431IPW, TL431CPW trades extended temperature range for lower unit cost in commercial-grade applications; versus TLVH431QDBVR, it offers higher reference voltage, tighter tolerance, and broader output adjustability-making TL431CPW the preferred choice for precision mid-to-high-voltage feedback loops.
Availability
TL431CPW is available at Aetrix Electronics and suitable for industrial power supplies, isolated DC-DC converters, and voltage monitoring systems requiring stable component supply with guaranteed long-term sourcing.
Supply support for TL431CPW 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 expertise in precision reference design.
The TL431 product line was engineered specifically for high-accuracy, low-drift shunt regulation in isolated and non-isolated power conversion-targeting cost-sensitive yet performance-critical applications across industrial, computing, and communications markets.
FAQ
What is the reference voltage tolerance of TL431CPW at 25°C?
The TL431CPW has a ±0.5% initial reference voltage tolerance at 25°C, corresponding to the B-grade specification. This means its Vref falls between 2.483 V and 2.507 V under nominal conditions, enabling high-accuracy feedback without external trimming. The value is confirmed in TI's SLVS543P datasheet Section 7.11 for TL431BC variants in TSSOP-8 packaging.
Does TL431CPW support operation beyond 85°C ambient temperature?
No-TL431CPW is a C-grade device characterized for 0°C to 70°C free-air temperature operation. While absolute maximum junction temperature is 150°C, sustained operation above 70°C ambient risks exceeding recommended conditions and degrading long-term stability. For −40°C to 85°C operation, select TL431IPW or TL431I variants instead.
What is the minimum cathode current required for TL431CPW regulation?
The TL431CPW requires a minimum cathode current (Imin) of 0.4 mA to maintain regulation, as specified in TI's datasheet Section 7.11. Below this threshold, the device exits active regulation and behaves like an open circuit. Designers must ensure feedback network and optocoupler LED current collectively meet or exceed this value across all operating conditions.
Can TL431CPW replace a standard 3.3 V Zener diode directly?
Yes-TL431CPW can replace a 3.3 V Zener by configuring external resistors R1 and R2 to set Vout = 3.3 V using the formula Vout = Vref × (1 + R1/R2). Its 0.2 Ω dynamic impedance and 0.5% tolerance deliver significantly better regulation accuracy and thermal stability than typical 5% tolerance Zeners, especially under varying load or temperature.
Is the thermal pad on TL431CPW's TSSOP-8 package electrically connected?
Yes-the exposed thermal pad on the TL431CPW (PW package) is internally connected to the ANODE pin (Pin 5). It must be soldered to a grounded copper pour or thermal plane to ensure proper heat dissipation and electrical reference integrity. Leaving it floating compromises thermal performance and may affect regulation stability under high-current conditions.
TL431CPW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Series:
- -
- Packaging:
- Tube
- 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-TSSOP
TL431CPW FAQ
1.How can I place an order for TL431CPW through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431CPW 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 TL431CPW reliable?
The price and inventory of TL431CPW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431CPW is usually 5 days.
3.What payment methods are accepted for TL431CPW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431CPW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431CPW?
TL431CPW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431CPW 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 TL431CPW?
For technical support, including TL431CPW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431CPW requirements.
6.How does Aetrix verify that TL431CPW is sourced from the original manufacturer or authorized distributors?
All TL431CPW 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 TL431CPW meets industry standards.
7.What is the process for return or replacement of TL431CPW?
All TL431CPW units undergo pre-shipment inspection (PSI). If there is an issue with TL431CPW, 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 TL431CPW part is unused and in its original packaging.
Return procedure for TL431CPW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431CPW Tags
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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
-
LM4040DIM3X-2.5/NOPB
Texas Instruments
-
LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
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