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Texas Instruments TL1431CPWR
- Part No.:
- TL1431CPWR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
TL1431CPWR.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,315
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Product details
Overview
TL1431CPWR from Texas Instruments is a precision programmable shunt voltage reference IC with 0.4% initial voltage tolerance, 0.2Ω typical output impedance, and 500ns fast turnon. It operates as an adjustable 2.5V–36V reference using two external resistors and serves as a Zener diode replacement in secondary-side regulation of flyback SMPSs.
For engineers reviewing the TL1431CPWR datasheet, TL1431CPWR pinout, TL1431CPWR application, or TL1431CPWR equivalent, this page delivers verified electrical parameters, validated TSSOP-8 pin functions, confirmed thermal and stability behavior, and real-world implementation guidance for voltage monitoring, error amplification, and programmable regulation circuits.
Technical Context
The TL1431CPWR integrates a 2.5V bandgap reference and high-gain transconductance amplifier in a single die, enabling closed-loop regulation via resistive feedback between CATHODE and REF pins. Its internal Darlington output stage supports sink currents from 1mA to 100mA while maintaining sharp turnon and low dynamic impedance.
It operates in two primary functional modes: open-loop comparator (with integrated reference) and closed-loop shunt regulator. Stability is internally compensated-no external capacitor required-but load capacitance up to 1µF remains within safe operating boundaries per Figure 5-12, provided cathode current exceeds 1mA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500V ±10mV at 25°C; enables precise 2.5V–36V programmable output via resistor divider |
| Initial Tolerance | ±0.4% at 25°C; ensures ≤10mV absolute error in reference setting without calibration |
| Output Impedance | 0.2Ω typical (≤0.4Ω max); minimizes output voltage shift under 1–100mA cathode load variation |
| Turnon Time | 500ns; supports fast transient response in clamp and protection circuits |
| Operating Temperature | 0°C to 70°C (commercial grade); validated for stable regulation across full range |
| Cathode Voltage Range | 2.5V to 36V; allows direct use in 5V, 12V, 24V, and 36V power rails without level-shifting |
| Reference Input Current | 1.5–2.5µA typical at 25°C; enables high-impedance feedback networks with minimal loading error |
Pinout & Package
TSSOP-8 package (4.40mm × 3.00mm body), moisture-sensitive level 1, lead-free and RoHS compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Current sink output | Primary regulated node; connects to supply rail or feedback point; sinks 1–100mA |
| ANODE (Pins 2, 3, 6, 7) | Common reference ground | Internally tied together; must be connected to system ground or return path |
| REF (Pin 8) | Feedback input | Senses voltage divider midpoint; forces CATHODE to maintain 2.5V relative to ANODE |
| NC (Pins 4, 5) | No internal connection | Not bonded; must remain unconnected or grounded per layout best practice |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage | Programmable 2.5V–36V via two external resistors-no trimming required for most applications |
| Low output impedance | 0.2Ω typical ensures <1mV output shift per 5mA load change-critical for tight-regulation SMPS feedback |
| Fast turnon | 500ns propagation enables real-time overvoltage clamping and fast comparator response |
| Zener replacement capability | Replaces discrete Zeners with superior accuracy, temperature stability, and sink-current headroom |
| Internal compensation | Stable operation with zero external capacitor-reduces BOM count and PCB area in space-constrained designs |
Applications
| Secondary-Side Regulation | Voltage Monitoring |
|---|---|
Use Scenario: Isolated flyback converter with optocoupler feedback loop. IC Role / Device Role / Timing Role: Shunt reference and error amplifier on secondary side, comparing output voltage against 2.5V reference to drive optocoupler LED. Use Value: Enables ±1% output regulation across line/load/temperature without primary-side sensing or complex compensation. |
Use Scenario: Overvoltage detection circuit protecting microcontroller I/O or battery charging path. IC Role / Device Role / Timing Role: Precision comparator with integrated 2.5V reference; triggers shutdown when sensed voltage exceeds threshold. Use Value: Eliminates external reference and reduces component count by 3–4 parts versus discrete op-amp + Zener solution. |
| Adjustable Power Supply | Comparator With Integrated Reference |
Use Scenario: Lab-grade bench power supply with digitally controlled output voltage. IC Role / Device Role / Timing Role: Programmable shunt reference in feedback network of linear or switching regulator. Use Value: Supports 0.1V resolution down to 2.5V and up to 36V with <0.5% total error including resistor drift. |
Use Scenario: Threshold detection in industrial sensor interface (e.g., 4–20mA loop monitor). IC Role / Device Role / Timing Role: Open-loop comparator comparing analog signal to built-in 2.5V reference. Use Value: Removes need for external reference IC and biasing network-reducing cost and board space by >30%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBVR | Same 2.5V reference, 0.5% initial tolerance (vs. TL1431CPWR's 0.4%), SO-8 package | Lower accuracy; slightly higher output impedance (0.3Ω typ); identical functional block diagram | Select when 0.5% tolerance suffices and SO-8 footprint is preferred over TSSOP-8 |
| LM431ACM/NOPB | 2.5V reference, 1% initial tolerance, TO-92 or SO-8; no guaranteed 500ns turnon spec | Higher temperature coefficient (92ppm/°C vs. ~50ppm/°C for TL1431C); limited sink current (100mA max but derated above 70°C) | Choose for cost-sensitive, non-critical applications where 1% tolerance and slower response are acceptable |
Compared with TL431CDBVR and LM431ACM/NOPB, the TL1431CPWR delivers tighter initial accuracy, lower output impedance, and faster turnon-making it optimal for high-performance flyback regulation and precision monitoring where stability and speed are design-critical.
Availability
TL1431CPWR is available at Aetrix Electronics and suitable for secondary-side regulation in flyback SMPSs, voltage monitoring in industrial control systems, and adjustable power supplies requiring stable component supply across production lifecycles.
Supply support for TL1431CPWR 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 TL1431 product line was designed for high-accuracy, low-drift shunt reference applications in power conversion, industrial automation, and telecom infrastructure-emphasizing robustness, wide voltage range, and ease of integration.
FAQ
What is the maximum cathode voltage rating for TL1431CPWR?
The TL1431CPWR has an absolute maximum cathode voltage (VKA) of 37V, with recommended operation up to 36V. Exceeding 37V risks permanent damage. This rating applies with respect to the ANODE pin, which serves as the common reference node-ensuring safe use in 24V and 36V industrial power rails when properly biased.
Can TL1431CPWR replace a Zener diode directly in existing designs?
Yes, TL1431CPWR can directly replace Zener diodes in most shunt regulation applications. Unlike Zeners, it offers 0.4% initial tolerance, 0.2Ω output impedance, and programmable 2.5V–36V output via two resistors. No layout changes are needed if ANODE is grounded and CATHODE/REF connections match the Zener's anode/cathode orientation-but verify minimum cathode current (≥1mA) is met.
Does TL1431CPWR require an external capacitor for stability?
No, TL1431CPWR is internally compensated and stable with zero external capacitor between CATHODE and ANODE. However, if downstream circuitry presents capacitive load (e.g., optocoupler input), consult Figure 5-12 in the datasheet: stability is maintained for CL ≤ 1µF when IKA ≥ 1mA and VKA ≤ 15V-no additional compensation components required.
What is the minimum cathode current needed for regulation in TL1431CPWR?
The TL1431CPWR requires a minimum cathode current (Imin) of 0.45mA to 1mA (typical 0.6mA) to enter and maintain regulation. Below this threshold, the internal amplifier cannot sustain sufficient gain, causing reference voltage collapse. Ensure external biasing (e.g., via RSUP) delivers ≥1mA under worst-case conditions-including lowest input voltage and highest temperature.
How does TL1431CPWR behave in open-loop comparator mode?
In open-loop mode, TL1431CPWR functions as a high-gain comparator with integrated 2.5V reference: when REF voltage exceeds 2.5V, CATHODE sinks current; below 2.5V, it remains off. This enables simple overvoltage detection without external references. The 500ns turnon ensures sub-microsecond response-ideal for fast fault signaling in power systems using TL1431CPWR.
TL1431CPWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±0.4%
- 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
TL1431CPWR FAQ
1.How can I place an order for TL1431CPWR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431CPWR 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 TL1431CPWR reliable?
The price and inventory of TL1431CPWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431CPWR is usually 5 days.
3.What payment methods are accepted for TL1431CPWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431CPWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431CPWR?
TL1431CPWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431CPWR 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 TL1431CPWR?
For technical support, including TL1431CPWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431CPWR requirements.
6.How does Aetrix verify that TL1431CPWR is sourced from the original manufacturer or authorized distributors?
All TL1431CPWR 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 TL1431CPWR meets industry standards.
7.What is the process for return or replacement of TL1431CPWR?
All TL1431CPWR units undergo pre-shipment inspection (PSI). If there is an issue with TL1431CPWR, 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 TL1431CPWR part is unused and in its original packaging.
Return procedure for TL1431CPWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431CPWR 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
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LM4040DIM3X-2.5/NOPB
Texas Instruments
-
LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
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