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Texas Instruments TL1431MFKB
- Part No.:
- TL1431MFKB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 20-CLCC
- Datasheet:
-
TL1431MFKB.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% 20CLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,718
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Product details
Overview
TL1431MFKB 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 across –55°C to 125°C, sinks 1–100mA cathode current, and serves as a Zener diode replacement in secondary-side regulation of flyback SMPSs.
For engineers reviewing the TL1431MFKB datasheet, TL1431MFKB pinout, TL1431MFKB application, or TL1431MFKB equivalent, this page delivers verified thermal stability data, military-grade operating range confirmation, cathode-to-reference functional relationship, and real-world design constraints for shunt regulator layout and stability boundary compliance.
Technical Context
The TL1431MFKB integrates an internal 2.5V bandgap reference and high-gain transconductance amplifier driving a Darlington sink output stage. Its closed-loop operation relies on feedback from cathode to REF to force the reference pin to ~2.5V, enabling precise voltage or current regulation without external compensation.
It supports both open-loop comparator mode (with integrated reference) and closed-loop error amplifier mode. Stability is maintained up to 10µF load capacitance per Figure 5-12, with cathode voltage sensitivity to supply variation quantified as –1.1 to –2 mV/V over –55°C to 125°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V ±15 mV at 25°C; ±25 mV over full –55°C to 125°C range - sets base accuracy for all regulated outputs |
| Initial Tolerance | 0.4% at 25°C - enables ≤10 mV absolute error in 2.5V reference configuration |
| Output Impedance | 0.2 Ω typical at 1–100 mA, ≤1 kHz - ensures <20 mV droop under 100 mA load step |
| Cathode Voltage Range | 2.5 V to 36 V - supports wide-range adjustable shunt regulation without external series pass element |
| Operating Temperature | –55°C to 125°C - qualified for military/aerospace systems requiring extended thermal robustness |
| Sink Current Range | 1 mA to 100 mA - defines minimum bias and maximum regulation capability in shunt topology |
| Reference Input Current | 1.5–2.5 µA at 25°C; ≤5 µA over full temperature range - determines R1/R2 resistor sizing impact on output accuracy |
Pinout & Package
LCCC (20-pin) ceramic package, 8.89 mm × 8.89 mm body size, hermetically sealed for high-reliability military applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 2) | Current sink output | Main regulated node; connects to power rail being controlled; carries full load/sink current |
| REF (Pin 20) | Reference input | Sense point for feedback divider; must receive ≥5 µA bias current to enable regulation |
| ANODE (Pin 15) | Common return | Typically connected to system ground or low-side return path; forms reference potential for REF and VKA |
| NC (Pins 1,3–14,16–19) | No internal connection | Unbonded; must remain unconnected and unstubbed to avoid parasitic coupling or EMI |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable 2.5–36V output | Enables single BOM part to support multiple output rails using only two precision resistors |
| 0.2Ω dynamic impedance | Minimizes load-induced voltage shift in precision current-sensing and voltage-clamp circuits |
| Fast 500ns turn-on | Supports transient-responsive overvoltage protection and fast-switching clamp applications |
| Military temperature rating | Validates performance continuity in avionics, defense electronics, and downhole instrumentation |
| Internal bandgap reference | Eliminates need for external reference IC in comparator or error amplifier configurations |
Applications
| Secondary-Side Flyback Regulation | Zener Diode Replacement |
|---|---|
Use Scenario: Isolated DC-DC converter where primary-side controller lacks direct output sensing. IC Role / Device Role / Timing Role: Shunt regulator providing feedback signal to optocoupler, closing voltage loop across isolation barrier. Use Value: Enables ±1% output regulation without transformer auxiliary winding or secondary-side controller IC. | Use Scenario: Voltage clamping or reference generation in high-temperature analog front-ends. IC Role / Device Role / Timing Role: Precision programmable shunt element replacing discrete Zener diodes with poor tempcos and tolerance. Use Value: Reduces drift to <50 ppm/°C and improves initial accuracy from ±5% to ±0.4%. |
| Voltage Monitoring System | Comparator with Integrated Reference |
Use Scenario: Power-rail supervision in aerospace power management units. IC Role / Device Role / Timing Role: Threshold detector comparing monitored rail against programmable trip point derived from REF feedback. Use Value: Eliminates external reference and reduces component count while maintaining –55°C to 125°C operational integrity. | Use Scenario: Overvoltage lockout circuit in MIL-STD-1275 compliant 28V systems. IC Role / Device Role / Timing Role: Open-loop comparator using internal 2.5V reference to trigger shutdown when input exceeds set threshold. Use Value: Achieves sub-microsecond response with no external reference sourcing or trimming components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL1431MFK | Same die, identical electrical specs, but non-burn-in screened LCCC package | Not qualified for Class B or Class S military screening; lower reliability assurance | Select TL1431MFKB when MIL-PRF-38535 Class B or S compliance is required |
| TL431MJB | Same architecture, but older process; 1% initial tolerance, wider VI(dev) (±50 mV), higher II(ref) (≤10 µA) | Lacks 0.4% grade and tighter thermal drift; limited to less demanding military subsystems | Choose TL1431MFKB for designs requiring guaranteed 0.4% accuracy and <25 mV total reference deviation over temperature |
Compared with TL1431MFK and TL431MJB, the TL1431MFKB provides superior initial accuracy, tighter thermal drift control, and full MIL-PRF-38535 Class B qualification-making it the only option for precision-regulated, high-reliability military power systems where reference stability directly impacts mission-critical functionality.
Availability
TL1431MFKB is available at Aetrix Electronics and suitable for aerospace power supplies, defense avionics, and downhole instrumentation requiring stable component supply under extended temperature stress and long-term reliability validation.
Supply support for TL1431MFKB 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 high-reliability analog ICs.
The TL1431 product line was designed specifically for precision voltage referencing and error amplification in harsh-environment power systems, emphasizing military-grade thermal stability, low-output-impedance regulation, and Zener-replacement versatility.
FAQ
What is the maximum cathode voltage rating for TL1431MFKB?
The TL1431MFKB has an absolute maximum cathode voltage (VKA) of 37 V, with recommended operating range up to 36 V referenced to ANODE. Exceeding 37 V risks permanent damage. This rating is validated across the full –55°C to 125°C operating range and applies to the LCCC package's internal structure and junction design.
Does TL1431MFKB require an external output capacitor for stability?
No, the TL1431MFKB is internally compensated and remains stable without any output capacitor between CATHODE and ANODE. However, capacitive loads up to 10 µF are supported per Figure 5-12 in the datasheet, provided they fall within the stable region defined by cathode current and voltage conditions.
What is the minimum cathode current needed for regulation in TL1431MFKB?
The TL1431MFKB requires a minimum cathode current (Imin) of 0.45 mA at 25°C to enter and maintain regulation. At –55°C or 125°C, design margin should allow ≥1 mA to ensure reliable startup and closed-loop operation across the full military temperature range.
How does the REF pin function in TL1431MFKB closed-loop operation?
In closed-loop operation, the REF pin serves as the high-impedance sense input that the internal amplifier forces to 2.5 V by adjusting cathode current. It must be biased with ≥5 µA (per TL1431M specs) via the feedback resistor network; floating or unterminated REF will disable regulation.
Can TL1431MFKB be used as a standalone comparator?
Yes, the TL1431MFKB functions as a comparator with integrated 2.5 V reference in open-loop mode. When cathode current ≥1 mA is supplied and no feedback is applied to REF, the device saturates based on whether the voltage at REF exceeds 2.5 V - enabling simple overvoltage or undervoltage detection without external reference components.
TL1431MFKB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 20-CLCC
- Series:
- -
- Packaging:
- Tube
- 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:
- 37V
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-LCCC (8.89x8.89)
TL1431MFKB FAQ
1.How can I place an order for TL1431MFKB through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431MFKB 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 TL1431MFKB reliable?
The price and inventory of TL1431MFKB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431MFKB is usually 5 days.
3.What payment methods are accepted for TL1431MFKB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431MFKB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431MFKB?
TL1431MFKB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431MFKB 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 TL1431MFKB?
For technical support, including TL1431MFKB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431MFKB requirements.
6.How does Aetrix verify that TL1431MFKB is sourced from the original manufacturer or authorized distributors?
All TL1431MFKB 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 TL1431MFKB meets industry standards.
7.What is the process for return or replacement of TL1431MFKB?
All TL1431MFKB units undergo pre-shipment inspection (PSI). If there is an issue with TL1431MFKB, 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 TL1431MFKB part is unused and in its original packaging.
Return procedure for TL1431MFKB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL1431MFKB Tags
-
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
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LM4040DIM3-2.5/NOPB
Texas Instruments
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AZ431LANTR-G1
Diodes Incorporated
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