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Texas Instruments TL1431CLPM
- Part No.:
- TL1431CLPM
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
TL1431CLPM.pdf
- Description:
- VOLTAGE REFERENCE
- Quantity:
- Payment:
- Shipping:
Inventory:506,000
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Product details
Overview
TL1431CLPM from Texas Instruments is a precision programmable shunt voltage reference IC with 0.4% initial voltage tolerance, 0.2Ω typical output impedance, and fast 500ns turn-on time. It operates as an adjustable 2.5V–36V reference or error amplifier in secondary-side regulation of flyback SMPSs, replacing discrete Zener diodes in onboard regulation and voltage monitoring circuits.
For engineers reviewing the TL1431CLPM datasheet, TL1431CLPM pinout, TL1431CLPM application, or TL1431CLPM equivalent, this page delivers verified electrical specs, TO-92 package details, thermal metrics, functional modes (open/closed loop), and real-world implementation guidance for stable shunt regulation and comparator use.
Technical Context
The TL1431CLPM integrates a 2.5V bandgap reference and high-gain transconductance amplifier driving an internal Darlington sink stage. Its closed-loop operation relies on resistive feedback between CATHODE and REF pins to regulate output voltage per VOUT = VREF(1 + R1/R2) + IREF·R1, with IREF ≤ 3µA over 0°C–70°C.
In open-loop mode, it functions as a comparator with integrated reference: REF pin serves as threshold input, CATHODE as active-low output. Minimum cathode current (Imin = 0.45–1mA) ensures proper biasing across the commercial temperature range (0°C to 70°C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VREF (initial) | 2.500 V ±0.4% at 25°C - sets baseline accuracy for programmable output voltage calculation |
| VREF temp drift | ±20 mV over 0°C to 70°C - defines worst-case reference deviation in commercial applications |
| Output impedance | 0.2 Ω typical at 1kHz - enables low-impedance regulation with minimal load-induced voltage shift |
| Cathode current range | 1 mA to 100 mA - supports robust sink capability for error amplification and shunt regulation |
| Turn-on time | 500 ns - ensures rapid response in dynamic clamp and protection circuits |
| Reference input current | ≤3 µA max over 0°C–70°C - minimizes resistor-divider loading error in precision feedback networks |
| Absolute max VK A | 37 V - defines safe operating ceiling above maximum 36V programmable output |
Pinout & Package
TL1431CLPM uses the TO-92 (LP) package: 4.83mm × 3.68mm body, through-hole mounting, 3-pin configuration with ANODE (pin 2), CATHODE (pin 1), and REF (pin 3). No NC pins; all terminals are electrically active.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (pin 1) | Shunt current output / regulated voltage node | Sinks up to 100mA; voltage at this pin is controlled by REF feedback; connects to output rail in shunt regulator topology |
| ANODE (pin 2) | Common return / ground reference | Internally tied to all ANODE terminals; serves as voltage reference point for VK A and VREF; typically connected to system ground or negative rail |
| REF (pin 3) | Threshold input / feedback sense node | Compares external voltage to internal 2.5V reference; requires ≥5µA bias current; connects to resistor divider midpoint in adjustable configurations |
Key Features
| Feature | Design Value |
|---|---|
| 0.4% initial VREF tolerance | Enables ±1% total output accuracy in 2.5V–36V programmable supplies without trimming |
| 0.2Ω output impedance | Reduces load regulation error to <2mV per 10mA load change at 5V output |
| 500ns turn-on time | Supports fast transient response in overvoltage clamping and power-good detection |
| 1mA–100mA sink current | Permits direct interface with optocoupler LEDs in isolated SMPS feedback loops without external drivers |
| Internal compensation | Eliminates need for external compensation capacitor in most shunt regulator designs |
Applications
| Secondary-Side Regulation | Zener Diode Replacement |
|---|---|
Use Scenario: Isolated flyback converter with optocoupler feedback for AC/DC adapters and industrial PSUs. IC Role / Device Role / Timing Role: Shunt regulator and error amplifier on secondary side; compares output voltage to 2.5V reference and drives optocoupler LED current. Use Value: Enables precise ±1% output regulation across line/load/temperature while reducing component count vs. discrete Zener+transistor solutions. |
Use Scenario: Overvoltage protection clamp in DC-DC converter output stage or microcontroller supply rail. IC Role / Device Role / Timing Role: Adjustable shunt reference providing sharp turn-on knee and low dynamic impedance at clamping threshold. Use Value: Replaces 2.5V–36V Zener diodes with superior thermal stability, lower leakage (<0.5µA off-state), and tighter initial tolerance. |
| Voltage Monitoring | Comparator with Integrated Reference |
Use Scenario: Power-rail supervision in telecom line cards and FPGA power sequencing. IC Role / Device Role / Timing Role: Precision threshold detector comparing monitored rail to user-set voltage via resistor divider on REF pin. Use Value: Eliminates need for external reference IC; achieves <10mV trip-point accuracy over 0°C–70°C with minimal BOM impact. |
Use Scenario: Window comparator input stage or battery voltage alert circuit in portable instrumentation. IC Role / Device Role / Timing Role: Open-loop comparator using internal 2.5V reference and high-gain amplifier; CATHODE outputs active-low signal. Use Value: Provides rail-to-rail compatible comparison with built-in reference, avoiding mismatch errors from dual external references. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar programmable shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBVR | SOIC-8 package; 2% initial tolerance; higher 2.5V ±2% VREF spec; 0.3Ω typical zKA | Lower cost, less precision; suited for non-critical regulation where 2% output tolerance is acceptable | Select TL431CDBVR only when board space allows SOIC-8 and ±2% output accuracy suffices. |
| TL1431ILP | Same TO-92 package; extended industrial temp range (–40°C to 105°C); identical 0.4% VREF tolerance | Required for operation beyond 70°C ambient, e.g., under-hood automotive modules or high-power industrial enclosures | Choose TL1431ILP when thermal environment exceeds 70°C but TO-92 form factor must be retained. |
Compared with TL1431CLPM, TL431CDBVR trades precision for cost and package flexibility, while TL1431ILP maintains identical accuracy and footprint but extends thermal capability-making TL1431CLPM optimal for cost-sensitive commercial designs within 0°C–70°C.
Availability
TL1431CLPM is available at Aetrix Electronics and suitable for secondary-side regulation in flyback SMPSs, Zener diode replacement in voltage clamps, and precision voltage monitoring requiring stable component supply across industrial, telecom, and computing applications.
Supply support for TL1431CLPM 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 family was designed as a drop-in upgrade to discrete Zener-based references, delivering programmable 2.5V–36V shunt regulation with improved thermal stability, lower output impedance, and integrated error amplification for isolated power supplies.
FAQ
What is the maximum cathode voltage rating for TL1431CLPM?
The absolute maximum cathode-to-anode voltage (VK A) for TL1431CLPM is 37 V, with recommended operation up to 36 V. Exceeding 37 V risks permanent damage. This rating is defined with respect to the ANODE pin, which serves as the common reference point in all TL1431CLPM configurations.
How does TL1431CLPM achieve adjustable output voltage?
TL1431CLPM achieves adjustable output voltage (2.5V to 36V) using two external resistors forming a voltage divider between CATHODE and ANODE, with the midpoint connected to the REF pin. The output follows VOUT = VREF(1 + R1/R2) + IREF·R1, where VREF = 2.5V and IREF ≤ 3 µA over 0°C–70°C. TL1431CLPM's internal amplifier forces REF to 2.5V, regulating the CATHODE voltage accordingly.
Can TL1431CLPM operate without an output capacitor?
Yes, TL1431CLPM is internally compensated and remains stable without an output capacitor between CATHODE and ANODE. This eliminates mandatory external capacitance in basic shunt regulator designs. However, if the downstream load presents significant capacitance (e.g., >1nF), stability must be verified against Figure 5-12 in the TL1431CLPM datasheet to avoid oscillation.
What is the minimum cathode current required for regulation in TL1431CLPM?
The minimum cathode current (Imin) required for TL1431CLPM to maintain regulation is 0.45 mA at 25°C and up to 1 mA across the full 0°C–70°C operating range. Below this threshold, the device exits its linear region and cannot sustain accurate reference tracking-critical for reliable startup and light-load performance in TL1431CLPM-based circuits.
Is TL1431CLPM pin-compatible with other TL1431 variants?
TL1431CLPM shares the same TO-92 (LP) 3-pin pinout (CATHODE–ANODE–REF) with TL1431ILP and TL1431MLP, making them mechanically and electrically interchangeable on PCBs. However, temperature ratings differ: TL1431CLPM is rated for 0°C–70°C, while TL1431ILP covers –40°C–105°C and TL1431MLP –55°C–125°C-so thermal validation is required when substituting.
TL1431CLPM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- Series:
- -
- Packaging:
- Bulk
- 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:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL1431CLPM FAQ
1.How can I place an order for TL1431CLPM through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431CLPM 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 TL1431CLPM reliable?
The price and inventory of TL1431CLPM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431CLPM is usually 5 days.
3.What payment methods are accepted for TL1431CLPM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431CLPM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431CLPM?
TL1431CLPM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431CLPM 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 TL1431CLPM?
For technical support, including TL1431CLPM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431CLPM requirements.
6.How does Aetrix verify that TL1431CLPM is sourced from the original manufacturer or authorized distributors?
All TL1431CLPM 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 TL1431CLPM meets industry standards.
7.What is the process for return or replacement of TL1431CLPM?
All TL1431CLPM units undergo pre-shipment inspection (PSI). If there is an issue with TL1431CLPM, 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 TL1431CLPM part is unused and in its original packaging.
Return procedure for TL1431CLPM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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