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Texas Instruments TL1431CDR
- Part No.:
- TL1431CDR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL1431CDR.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:11,227
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Product details
Overview
TL1431CDR from Texas Instruments is a precision programmable shunt voltage reference IC with 0.4% initial voltage tolerance, 0.2Ω typical output impedance, and adjustable output voltage from 2.5V to 36V via two external resistors. It operates as a Zener replacement or error amplifier in secondary-side regulation of flyback SMPSs, voltage monitoring, and adjustable power supplies.
For engineers reviewing the TL1431CDR datasheet, TL1431CDR pinout, TL1431CDR application, or TL1431CDR equivalent, this page delivers verified electrical characteristics, SOIC-8 package mapping, thermal performance data, functional mode distinctions (open-loop comparator vs. closed-loop regulator), and real-world design constraints including minimum cathode current (0.45mA), reference input current (≤2.5µA), and stability boundary conditions for capacitive loading.
Technical Context
The TL1431CDR integrates a 2.5V bandgap reference and high-gain transconductance amplifier driving an internal Darlington sink stage, enabling precise voltage clamping and error amplification without external compensation. Its open-loop operation supports comparator use with integrated reference; closed-loop configuration enables adjustable shunt regulation via resistive feedback between CATHODE and REF pins.
It functions across 0°C to 70°C (commercial grade), requires ≥1mA cathode current for regulation, and maintains <20mV reference voltage deviation over temperature. The device achieves fast turnon (500ns) and low dynamic impedance (0.2Ω at 1–100mA) due to active output circuitry and internal compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500V ±10mV at 25°C; sets regulated output point in feedback networks |
| Initial Tolerance | ±0.4% at 25°C; enables high-accuracy voltage setting without trimming |
| Output Impedance | 0.2Ω typical (≤0.4Ω max); ensures minimal load-induced voltage droop |
| Cathode Current Range | 1mA to 100mA sink capability; supports wide output power scaling in shunt regulators |
| Reference Input Current | ≤2.5µA at 25°C; minimizes resistor-divider loading error in precision feedback |
| Turnon Time | 500ns; suitable for fast transient response in clamp and protection circuits |
| Operating Temperature | 0°C to 70°C; validated for commercial-grade industrial and telecom power systems |
| Absolute Max Cathode Voltage | 37V; defines safe operating margin above 36V adjustable output limit |
Pinout & Package
TL1431CDR is packaged in an 8-pin SOIC (D package), 3.90mm × 4.90mm body size, with internally connected ANODE pins (pins 2, 3, 6, 7) for low-inductance ground return.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current output / voltage sensing node | Sinks regulated current; connects to output rail in shunt regulator topology |
| ANODE (Pins 2, 3, 6, 7) | Common reference/ground terminal | Internally bonded; must be tied to system ground or return path for stable biasing |
| REF (Pin 8) | Reference input threshold node | Senses voltage divider midpoint; forces CATHODE to maintain 2.5V relative to ANODE |
| NC (Pins 4, 5) | No internal connection | Unbonded; must remain unconnected to avoid parasitic coupling or ESD risk |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output Voltage | 2.5V to 36V via external R1/R2 divider; eliminates need for multiple fixed-voltage references |
| Low Reference Input Current | ≤2.5µA at 25°C; reduces resistor-divider power loss and ratio error in high-impedance feedback |
| Fast Turnon Response | 500ns; enables rapid clamping during overvoltage transients in power supply protection |
| Thermally Stable Reference | ≤20mV VI(dev) over 0°C–70°C; ensures consistent regulation across commercial ambient range |
| Zener Replacement Capability | Programmable knee voltage with sharp turnon; replaces discrete Zeners while improving accuracy and tempco |
| Internal Compensation | Stable without output capacitor; simplifies layout and avoids instability from stray capacitance |
Applications
| Secondary-Side Regulation | Zener Diode Replacement |
|---|---|
|
Use Scenario: Isolated flyback converter with optocoupler feedback loop on secondary side. IC Role / Device Role / Timing Role: Precision shunt reference generating error signal for optocoupler LED drive. Use Value: Enables ±1% output voltage regulation across line/load/temperature by replacing less accurate TL431 variants with tighter 0.4% initial tolerance. |
Use Scenario: Overvoltage clamp in DC-DC converter output stage. IC Role / Device Role / Timing Role: Adjustable voltage clamp referenced to 2.5V internal bandgap. Use Value: Provides sharp turnon (500ns) and low dynamic impedance (0.2Ω) for faster, lower-droop clamping than 5.1V Zener diodes. |
| Voltage Monitoring | Comparator with Integrated Reference |
|
Use Scenario: System-level brownout detection in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Threshold detector comparing supply rail against programmable reference voltage. Use Value: Eliminates external reference IC and reduces BOM count; 0.4% tolerance ensures reliable trip point across temperature. |
Use Scenario: Signal-level window comparator in battery management analog front-end. IC Role / Device Role / Timing Role: Open-loop comparator using internal 2.5V reference and high open-loop gain. Use Value: Reduces component count and PCB area versus op-amp + external reference solution; no external biasing required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDR | 1% initial tolerance (vs. TL1431CDR's 0.4%), same SOIC-8 package and pinout | Lower accuracy requirement; acceptable where ±1% output regulation suffices | Select TL431ACDR for cost-sensitive designs where tighter tolerance is unnecessary |
| TL1431IDR | Industrial temperature range (–40°C to 105°C) vs. commercial (0°C to 70°C); identical electrical specs | Required for extended ambient operation in outdoor or automotive-adjacent equipment | Choose TL1431IDR when operating beyond 70°C ambient or requiring wider thermal margin |
Compared with TL431ACDR, TL1431CDR delivers 2.5× tighter initial tolerance for higher-precision regulation; compared with TL1431IDR, it trades extended temperature capability for lower cost and qualification scope in commercial-grade systems.
Availability
TL1431CDR is available at Aetrix Electronics and suitable for secondary-side regulation in flyback SMPSs, voltage monitoring in industrial control systems, and Zener replacement in DC-DC output clamping requiring stable component supply and traceable sourcing.
Supply support for TL1431CDR 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.
TL1431CDR belongs to TI's precision shunt reference product line, designed specifically for high-accuracy voltage regulation, error amplification, and programmable clamping in isolated and non-isolated power converters.
FAQ
What is the maximum cathode voltage rating for TL1431CDR?
The absolute maximum cathode voltage (VKA) for TL1431CDR is 37V, with recommended operation up to 36V. This rating ensures safe operation when used as an adjustable shunt reference across a wide output voltage range. Exceeding 37V risks permanent damage. The TL1431CDR datasheet specifies this limit under Absolute Maximum Ratings section 5.1, and all voltage values are referenced to the ANODE pin.
Does TL1431CDR require an external output capacitor for stability?
No, TL1431CDR is internally compensated and remains stable without an external capacitor between CATHODE and ANODE. This simplifies layout and avoids instability from stray capacitance. However, if a capacitive load is present downstream (e.g., from connected circuitry), designers must consult Figure 5-12 (Stability Boundary Conditions) to ensure the combined load stays outside oscillation regions. The TL1431CDR datasheet confirms this in Section 7.3 and Figure 5-12.
What is the minimum cathode current needed for regulation in TL1431CDR?
The minimum cathode current (Imin) required for regulation in TL1431CDR is 0.45mA at 25°C, with a maximum of 1mA across the full 0°C to 70°C operating range. Supplying less than this prevents the internal amplifier from entering linear region, causing loss of regulation. This value is specified in Section 5.5 Electrical Characteristics – TL1431C and directly impacts feedback resistor sizing in shunt regulator designs using TL1431CDR.
How does TL1431CDR differ from TL431 in terms of accuracy and temperature range?
TL1431CDR offers 0.4% initial voltage tolerance at 25°C versus TL431ACDR's 1%, and is characterized for 0°C to 70°C operation - matching TL431C but with tighter spec. Both share SOIC-8 packaging and pin compatibility, but TL1431CDR's improved tolerance enables higher-precision regulation in commercial-grade power supplies. The TL1431CDR datasheet explicitly lists these parameters in Sections 1 (Features) and 5.5.
Can TL1431CDR be used as a comparator, and what configuration is required?
Yes, TL1431CDR can operate as a comparator in open-loop mode: connect the signal to be monitored to the REF pin, tie ANODE to ground, and monitor CATHODE output state. When REF voltage exceeds 2.5V, CATHODE sinks current; below 2.5V, it remains high-impedance. This configuration leverages the internal reference and high open-loop gain without feedback, as described in Section 7.4.1 and Figure 8-1 of the TL1431CDR datasheet.
TL1431CDR 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):
- 2.5V
- 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-SOIC
TL1431CDR FAQ
1.How can I place an order for TL1431CDR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431CDR 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 TL1431CDR reliable?
The price and inventory of TL1431CDR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431CDR is usually 5 days.
3.What payment methods are accepted for TL1431CDR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431CDR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431CDR?
TL1431CDR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431CDR 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 TL1431CDR?
For technical support, including TL1431CDR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431CDR requirements.
6.How does Aetrix verify that TL1431CDR is sourced from the original manufacturer or authorized distributors?
All TL1431CDR 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 TL1431CDR meets industry standards.
7.What is the process for return or replacement of TL1431CDR?
All TL1431CDR units undergo pre-shipment inspection (PSI). If there is an issue with TL1431CDR, 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 TL1431CDR part is unused and in its original packaging.
Return procedure for TL1431CDR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431CDR Tags
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