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Texas Instruments TL1431CDE4
- Part No.:
- TL1431CDE4
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL1431CDE4.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,051
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Product details
Overview
TL1431CDE4 from Texas Instruments is a precision programmable shunt voltage reference IC with 0.4% initial voltage tolerance at 25°C, 2.500 V nominal reference voltage (±10 mV), 0.2 Ω typical output impedance, and sink current capability from 1 mA to 100 mA. It operates as an adjustable 2.5 V–36 V reference in secondary-side regulation of flyback SMPSs, replacing Zener diodes in onboard voltage monitoring and error amplifier circuits.
For engineers reviewing the TL1431CDE4 datasheet, TL1431CDE4 pinout, TL1431CDE4 application, or TL1431CDE4 equivalent, this page delivers verified electrical specs, SOIC-8 package mapping, thermal resistance data (RθJA = 114.7 °C/W), functional mode distinctions (open-loop comparator vs. closed-loop regulator), and validated alternative parts for commercial-temperature power management designs.
Technical Context
The TL1431CDE4 integrates a 2.5 V bandgap reference and high-gain transconductance amplifier driving a Darlington sink output stage. Its internal architecture enables precise feedback control via external resistor dividers connected between cathode and reference pins, with the anode serving as common ground reference.
It supports two primary functional modes: open-loop operation as a comparator with integrated reference (requiring ≥1 mA cathode bias), and closed-loop operation as a shunt regulator or error amplifier (requiring ≥0.45 mA minimum cathode current for regulation). Thermal stability is specified over 0°C to 70°C, with ±20 mV max reference voltage deviation across that range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V ±10 mV at 25°C; enables accurate 2.5 V–36 V programmable output via R1/R2 divider |
| Initial Tolerance | 0.4% at 25°C; ensures ≤±10 mV absolute error before temperature or load effects |
| Output Impedance | 0.2 Ω typical at 1 kHz; maintains <±2 mV regulation error under 10 mA cathode current step |
| Cathode Current Range | 1 mA to 100 mA sink capability; supports direct drive of optocoupler LEDs or error amp inputs |
| Min Regulation Current | 0.45 mA at 25°C; defines lowest bias needed to enter linear regulation region |
| Temp Range | 0°C to 70°C (commercial); guarantees full spec compliance without derating in office/industrial environments |
| Turn-on Time | 500 ns; allows fast response in overvoltage clamp or dynamic reference switching applications |
Pinout & Package
TL1431CDE4 is housed in an 8-pin SOIC (D) package measuring 3.90 mm × 4.90 mm, with exposed pad not present and RoHS-compliant lead finish. Pin 1 is cathode (I/O), pins 2–3–6–7 are internally bonded anode terminals (O, grounded common), pin 8 is reference input (I), and pins 4–5 are no-connect.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | I/O current sink node | Primary output path for regulated shunt current; connects to SMPS feedback loop or optocoupler anode |
| ANODE (Pins 2, 3, 6, 7) | Common ground reference | Internally tied together; must be connected to system ground or return path for stable reference bias |
| REF (Pin 8) | Feedback input | Senses divided cathode voltage; forces cathode to 2.5 V when divider ratio matches target output |
| NC (Pins 4, 5) | No internal connection | Must remain unconnected; no routing or grounding required on PCB |
Key Features
| Feature | Design Value |
|---|---|
| Programmable Output Range | 2.5 V to 36 V via external resistors - eliminates need for multiple fixed-voltage references |
| Low Reference Current | 2.5 µA typical at 25°C - minimizes divider network power loss and improves accuracy at high R-values |
| Internal Compensation | Stable without external capacitor - simplifies layout and avoids instability from parasitic capacitance |
| Zener Replacement Capability | Sharp turn-on (500 ns) and low dynamic impedance - matches or exceeds Zener performance with tighter tolerance |
| Thermal Stability | ±20 mV max VI(ref) deviation over 0°C–70°C - enables reliable operation in non-temperature-controlled enclosures |
Applications
| Secondary-Side Flyback Regulation | Zener Diode Replacement |
|---|---|
Use Scenario: Isolated DC-DC converter where TL1431CDE4 senses output voltage on secondary side and drives optocoupler LED to regulate primary-side controller. IC Role / Device Role / Timing Role: Precision shunt reference and error amplifier providing feedback signal to isolated communication interface. Use Value: Enables ±1% output voltage regulation across line/load/temperature without secondary-side LDO, reducing BOM count and cost. |
Use Scenario: Replacing discrete 2.4 V–36 V Zener diodes in voltage clamping, overvoltage protection, or reference generation circuits. IC Role / Device Role / Timing Role: Active shunt regulator with programmable threshold and lower dynamic impedance than passive Zeners. Use Value: Delivers 0.4% initial accuracy and 0.2 Ω impedance versus typical 5% Zener tolerance and >10 Ω impedance, improving system precision. |
| Voltage Monitoring System | Comparator with Integrated Reference |
Use Scenario: Monitoring battery or rail voltage in industrial controllers, triggering alerts or shutdown when voltage falls outside 2.5 V–36 V window. IC Role / Device Role / Timing Role: Adjustable threshold detector using REF pin as comparator input and CATHODE as output driver. Use Value: Eliminates need for external reference IC and op-amp; single-component solution reduces footprint and component count. |
Use Scenario: Level detection in analog signal chains where a stable, known reference is required to compare against variable input signals. IC Role / Device Role / Timing Role: Open-loop comparator with built-in 2.5 V reference, sinking current when input exceeds threshold. Use Value: Reduces design complexity by integrating reference and comparator functions - no external voltage source or trimming needed. |
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 2.5 V reference, 0.4% tolerance, SO-8 package; higher ESD rating (HBM ±2 kV vs. TL1431CDE4's ±2 kV), identical RθJA (114.7 °C/W) | Identical functional scope; used interchangeably in commercial-temp flyback feedback and voltage monitor designs | Select TL431CDBVR if requiring TI's newer-generation process with enhanced latch-up immunity and same thermal profile |
| LM431ACM/NOPB | 2.5 V reference, 1% initial tolerance (vs. 0.4%), TO-92 and SO-8 options; RθJA = 157 °C/W in TO-92 but 114.7 °C/W in SO-8; wider temp range (−25°C to 85°C) | Lower accuracy limits use in tight-regulation SMPS; suitable for cost-sensitive voltage clamp or basic monitoring where ±1% is acceptable | Choose LM431ACM/NOPB only when budget constraints outweigh need for 0.4% tolerance and full 0°C–70°C spec compliance |
Compared with TL1431CDE4, TL431CDBVR offers identical precision and thermal behavior with updated process reliability, while LM431ACM/NOPB trades 2.5× worse initial tolerance and narrower temperature coverage for lower unit cost in non-critical applications.
Availability
TL1431CDE4 is available at Aetrix Electronics and suitable for secondary-side SMPS regulation, Zener replacement, voltage monitoring, and comparator-based level detection requiring stable component supply across industrial control, telecom power, and embedded computing programs.
Supply support for TL1431CDE4 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 delivering analog and embedded processing solutions, with leadership in power management, signal chain, and microcontrollers.
The TL1431 product line was designed specifically for precision shunt reference applications in isolated power supplies and analog monitoring systems, emphasizing low output impedance, wide output programming range, and robust thermal stability in commercial environments.
FAQ
What is the maximum cathode voltage supported by TL1431CDE4?
The TL1431CDE4 supports a maximum cathode voltage (VKA) of 36 V under recommended operating conditions. Absolute maximum rating is 37 V, but sustained operation above 36 V risks exceeding thermal limits or violating regulation accuracy specs. This 36 V ceiling enables safe use in 24 V and 32 V industrial rails, telecom -48 V derived outputs, and automotive 12 V/24 V systems with margin.
Can TL1431CDE4 operate without an external capacitor?
Yes, TL1431CDE4 is internally compensated and remains stable without any external capacitor between cathode and anode. This eliminates capacitor-related instability risks and simplifies layout. However, if downstream circuitry presents capacitive loading (e.g., optocoupler input capacitance), designers must verify operation against the stability boundary chart in Figure 5-12 of the TL1431CDE4 datasheet to avoid oscillation.
How does TL1431CDE4 differ from TL431 in practical design?
TL1431CDE4 and TL431 share identical electrical specs (0.4% tolerance, 2.5 V reference, 0.2 Ω impedance, SOIC-8 package), but TL1431CDE4 is characterized for 0°C–70°C commercial operation, while TL431 variants may offer extended temp grades. In practice, TL1431CDE4 is drop-in compatible with TL431 in commercial designs, with identical pinout, biasing, and feedback configuration - no schematic or layout changes required.
What is the minimum cathode current needed for regulation in TL1431CDE4?
The TL1431CDE4 requires a minimum cathode current (Imin) of 0.45 mA at 25°C to maintain regulation. Below this threshold, the internal amplifier exits linear region and reference accuracy degrades. Designers must ensure external bias networks (e.g., pull-up resistor from cathode to VOUT) deliver ≥0.45 mA even under worst-case conditions (min VOUT, max temperature) to guarantee stable 2.5 V reference at the REF pin.
Is TL1431CDE4 suitable for automotive applications?
No, TL1431CDE4 is rated only for the commercial temperature range (0°C to 70°C) and is not qualified for automotive use. For automotive applications requiring −40°C to 125°C operation, TI specifies the TL1431Q variant (e.g., TL1431QDBVR). Using TL1431CDE4 in automotive environments risks parametric drift, reduced reliability, and failure to meet AEC-Q100 stress test requirements.
TL1431CDE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tube
- 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-SOIC
TL1431CDE4 FAQ
1.How can I place an order for TL1431CDE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431CDE4 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 TL1431CDE4 reliable?
The price and inventory of TL1431CDE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431CDE4 is usually 5 days.
3.What payment methods are accepted for TL1431CDE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431CDE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431CDE4?
TL1431CDE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431CDE4 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 TL1431CDE4?
For technical support, including TL1431CDE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431CDE4 requirements.
6.How does Aetrix verify that TL1431CDE4 is sourced from the original manufacturer or authorized distributors?
All TL1431CDE4 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 TL1431CDE4 meets industry standards.
7.What is the process for return or replacement of TL1431CDE4?
All TL1431CDE4 units undergo pre-shipment inspection (PSI). If there is an issue with TL1431CDE4, 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 TL1431CDE4 part is unused and in its original packaging.
Return procedure for TL1431CDE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431CDE4 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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