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Texas Instruments TL431BCPW
- Part No.:
- TL431BCPW
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
TL431BCPW.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,255
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Product details
Overview
TL431BCPW from Texas Instruments is a precision programmable shunt voltage reference IC in TSSOP-8 package, delivering 2.483–2.507 V reference voltage (0.5% initial tolerance at 25°C), 6 mV max temperature drift over 0°C to 70°C, 0.2 Ω typical dynamic impedance, and 1–100 mA sink-current capability. It serves as an adjustable voltage reference in secondary-side regulation of flyback SMPSs.
For engineers reviewing the TL431BCPW datasheet, TL431BCPW pinout, TL431BCPW application, or TL431BCPW equivalent, this page provides verified electrical specs, thermal behavior, real-world use cases, and validated alternative options for industrial power supply design and Zener replacement scenarios.
Technical Context
The TL431BCPW implements a three-terminal adjustable shunt regulator architecture with an internal error amplifier, reference, and output transistor. Its sharp turn-on characteristic and low 0.2 Ω dynamic impedance enable stable closed-loop feedback in isolated DC/DC converters.
It operates across 0°C to 70°C (C-grade), supports cathode voltages from 2.5 V to 36 V, and requires only two external resistors to set output voltage. Reference input current remains tightly bounded (2–4 µA typ) with ≤1.2 µA deviation over temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (Vref) | 2.483–2.507 V at 25°C - enables precise 2.5 V-based feedback without calibration |
| Initial Tolerance | ±0.5% - meets tight regulation requirements in telecom and industrial SMPS |
| Temp Drift (VI(dev)) | ≤6 mV (0°C to 70°C) - ensures <0.01% output variation across commercial temp range |
| Dynamic Impedance | 0.2 Ω typical - maintains loop stability under fast load transients |
| Cathode Current Range | 1–100 mA - supports direct drive of optocoupler LEDs in isolated feedback paths |
| Reference Input Current | 2–4 µA - minimizes resistor-divider loading error in high-impedance setpoints |
| Max Cathode Voltage | 36 V - allows use in 24 V and 32 V bus applications with margin |
Pinout & Package
TSSOP-8 (PW) package: 3.0 mm × 4.4 mm body, 0.65 mm pitch, exposed thermal pad (not electrically connected), RoHS-compliant, moisture sensitivity level 2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CATHODE) | Shunt current output node | Connects to primary-side controller via optocoupler; sinks regulated current to maintain REF voltage |
| 2 (NC) | No internal connection | Unused pin; must be left floating or tied to ground per layout best practice |
| 3 (NC) | No internal connection | Unused pin; no internal bond wire; electrically isolated |
| 4 (REF) | Reference threshold input | Sense point for feedback divider; triggers regulation when voltage reaches ~2.495 V |
| 5 (ANODE) | Common return path | Typically connected to system ground or negative rail; defines voltage reference baseline |
| 6 (NC) | No internal connection | Unused pin; no function; avoid routing signals nearby to prevent coupling |
| 7 (NC) | No internal connection | Unused pin; no internal connection; leave unconnected |
| 8 (NC) | No internal connection | Unused pin; not bonded; no electrical role in operation |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% reference accuracy | Reduces need for post-manufacturing trimming in power supply feedback networks |
| 0.2 Ω dynamic impedance | Enables stable loop gain in optocoupler-coupled feedback without added compensation |
| 1–100 mA sink capability | Directly drives PC817/PC817x-series optocouplers without external transistor buffering |
| 6 mV max temp drift (0°C–70°C) | Ensures ±0.024% output variation across full commercial temperature range |
| Zener diode replacement | Eliminates wide-tolerance, high-noise, high-drift discrete Zeners in voltage monitoring circuits |
Applications
| Secondary-Side Regulation | Zener Diode Replacement |
|---|---|
|
Use Scenario: Isolated flyback converter with optocoupler feedback to primary-side PWM controller. IC Role / Device Role / Timing Role: Adjustable shunt reference setting feedback voltage threshold for error amplifier. Use Value: Enables accurate 5 V or 12 V output regulation despite transformer leakage and cross-regulation effects. |
Use Scenario: Precision voltage clamp in battery protection circuit or LDO enable threshold. IC Role / Device Role / Timing Role: Programmable voltage reference replacing fixed 2.5 V Zener diode. Use Value: Improves trip-point accuracy from ±5% (Zener) to ±0.5%, reducing false overvoltage shutdowns. |
| Voltage Monitoring | Adjustable Current Reference |
|
Use Scenario: Undervoltage lockout (UVLO) detection on 3.3 V microcontroller supply rail. IC Role / Device Role / Timing Role: Threshold comparator reference with integrated precision bandgap. Use Value: Triggers reset at exactly 3.0 V (via resistor divider), independent of supply ripple or temperature drift. |
Use Scenario: Constant-current LED driver with programmable brightness via analog dimming. IC Role / Device Role / Timing Role: Shunt reference defining current-sense voltage for op-amp-controlled MOSFET. Use Value: Delivers ±0.5% current accuracy across 10–100 mA range without calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDR | SOIC-8 package, same 0.5% tolerance and C-temp grade, but higher RθJA (97°C/W vs. 149°C/W) | Better board-level thermal dissipation in non-ventilated enclosures; less suitable for high-density TSSOP layouts | Select TL431BIDR when PCB space allows SOIC and thermal management prioritizes junction-to-ambient conduction |
| TLVH431BQDBVR | Lower 1.24 V reference, 0.5% tolerance, SOT-23-5, 6 mV drift (−40°C to 125°C), 1.5 µA Iref | Enables sub-2.5 V regulation (e.g., 1.8 V rails); wider temp range but incompatible pinout and voltage range | Choose TLVH431BQDBVR only when designing for 1.2–2.0 V outputs or extended industrial temperature operation |
Compared with TL431BCPW, TL431BIDR offers identical electrical performance in a thermally robust SOIC package, while TLVH431BQDBVR shifts the reference baseline downward and extends temperature coverage-neither is pin-compatible, requiring layout revision for substitution.
Availability
TL431BCPW is available at Aetrix Electronics and suitable for industrial power supplies, telecom DC/DC modules, and embedded voltage monitoring systems requiring stable component supply and long-term manufacturability.
Supply support for TL431BCPW 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 experience in precision reference design.
The TL431 product line delivers cost-effective, high-accuracy shunt references for power supply feedback, voltage supervision, and programmable thresholding in industrial, automotive, and consumer systems.
FAQ
What is the maximum cathode voltage rating for TL431BCPW?
The absolute maximum cathode-to-anode voltage (VKA) for TL431BCPW is 37 V, with recommended operating range from 2.5 V to 36 V. Exceeding 36 V during normal operation risks exceeding safe power dissipation limits and may degrade long-term reliability. The device maintains regulation integrity up to 36 V when paired with appropriate external resistors and thermal management.
Does TL431BCPW require external capacitors for stability?
TL431BCPW does not require external compensation capacitors for basic shunt regulation, but a 1 nF ceramic capacitor between REF and ANODE is recommended when driving long traces or optocouplers to suppress high-frequency oscillation. This improves phase margin in feedback loops where parasitic inductance exceeds 10 nH.
Can TL431BCPW replace a standard 2.5 V Zener diode directly?
Yes, TL431BCPW can directly replace a 2.5 V Zener diode in most applications, provided the anode is grounded and the cathode connects to the supply rail through a current-limiting resistor. Unlike Zeners, TL431BCPW delivers tighter tolerance (±0.5% vs. ±5%), lower dynamic impedance (0.2 Ω vs. 10–100 Ω), and minimal temperature drift-no circuit redesign is needed beyond verifying minimum cathode current (≥0.4 mA).
What is the reference input current (Iref) specification for TL431BCPW?
TL431BCPW exhibits a reference input current (Iref) of 2–4 µA typical at 25°C, with ≤1.2 µA deviation over 0°C to 70°C. This low, stable input current minimizes loading error in high-impedance resistor dividers-enabling use of >1 MΩ top resistors without significant setpoint inaccuracy.
Is TL431BCPW pin-compatible with other TL431 variants in TSSOP-8?
Yes, TL431BCPW shares identical TSSOP-8 (PW) pinout with all TL431x and TL432x variants in that package-including TL431ACPW, TL431AI PW, and TL432BCPW. Pin 1 is CATHODE, Pin 4 is REF, Pin 5 is ANODE, and Pins 2,3,6,7,8 are NC. No PCB layout change is required when upgrading between grades or temperature versions in the same package.
TL431BCPW 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:
- ±0.5%
- 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-TSSOP
TL431BCPW FAQ
1.How can I place an order for TL431BCPW through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BCPW 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 TL431BCPW reliable?
The price and inventory of TL431BCPW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BCPW is usually 5 days.
3.What payment methods are accepted for TL431BCPW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BCPW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BCPW?
TL431BCPW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BCPW 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 TL431BCPW?
For technical support, including TL431BCPW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BCPW requirements.
6.How does Aetrix verify that TL431BCPW is sourced from the original manufacturer or authorized distributors?
All TL431BCPW 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 TL431BCPW meets industry standards.
7.What is the process for return or replacement of TL431BCPW?
All TL431BCPW units undergo pre-shipment inspection (PSI). If there is an issue with TL431BCPW, 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 TL431BCPW part is unused and in its original packaging.
Return procedure for TL431BCPW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BCPW 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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