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STMicroelectronics TL1431ACL5T
- Part No.:
- TL1431ACL5T
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
TL1431ACL5T.pdf
- Description:
- IC VREF SHUNT ADJ 0.25% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,333
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Product details
Overview
TL1431ACL5T from STMicroelectronics is an adjustable precision shunt voltage reference IC designed for feedback regulation in switching and linear power supplies. It delivers 2.500 V nominal reference voltage with ±0.25% initial accuracy, operates over 1–100 mA cathode current, maintains 0.22 Ω typical dynamic impedance, and supports automotive-grade temperature range (−40 °C to +125 °C) in SOT23-5L package.
For engineers reviewing the TL1431ACL5T datasheet, TL1431ACL5T pinout, TL1431ACL5T application, or TL1431ACL5T equivalent, this page provides verified electrical parameters, validated pin functions, confirmed thermal performance, and real-world use cases in isolated DC-DC converters, battery management references, and programmable current sources.
Technical Context
The TL1431ACL5T implements a bandgap-based reference core with internal error amplifier and NPN output stage, configured as a 3-terminal adjustable shunt regulator. Its reference input (REF) senses external resistor divider voltage, while cathode (K) sinks current to maintain precise output voltage across anode (A) and cathode terminals.
It operates in closed-loop feedback by comparing REF voltage to internal 2.5 V bandgap; deviation drives cathode current to stabilize VKA. The device requires no external compensation for stable operation with capacitive loads up to 10 µF and exhibits guaranteed phase margin >45° at 1 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V (typical), ±0.25% initial tolerance - enables accurate 2.5–36 V output programming via two external resistors |
| Cathode Current Range | 1–100 mA - supports direct regulation of medium-power supplies without external pass transistor |
| Dynamic Impedance | 0.22 Ω (typical) - ensures minimal output voltage variation under load transients (e.g., <22 mV ΔV at 100 mA step) |
| Temp. Coefficient | ±13 ppm/°C (max) - guarantees ≤0.75 mV drift over −40 °C to +125 °C for high-stability feedback loops |
| Ref Input Current | 2.5 µA (typical) - allows high-value resistor dividers (e.g., 1 MΩ total) minimizing quiescent power loss |
| Voltage Deviation | ±3 mV over full temp. range - meets tight regulation requirements in automotive body control modules |
| ESD Rating | 2000 V HBM - withstands handling in standard assembly environments without additional protection |
Pinout & Package
SOT23-5L plastic surface-mount package (5-pin, 1.9 mm × 1.3 mm footprint, 1.1 mm height), RoHS-compliant, ECOPACK®2 rated.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (A) | Reference ground return path | Connected to system ground or power supply return; forms cathode-to-anode voltage (VKA) measurement point |
| Cathode (K) | Current sink output terminal | Sinks regulated current to maintain programmed VKA; connects to primary-side switch node in flyback converters |
| Reference (REF) | Feedback input | High-impedance input sensing resistor divider voltage; triggers regulation when ≥2.5 V |
| NC (Pin 4) | No connect | Internally unconnected; must be left floating or tied to ground per layout best practice |
| NC (Pin 5) | No connect | Internally unconnected; no electrical function; avoid routing signals or traces to this pad |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output Range | 2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-reference parts in BOM |
| Automotive Temperature Range | −40 °C to +125 °C operation - qualified per AEC-Q100 for engine bay and ADAS power rail monitoring |
| Low Dynamic Impedance | 0.22 Ω typical - sustains regulation during fast load steps in telecom DC-DC modules without added capacitance |
| High Initial Accuracy | ±0.25% VREF tolerance - reduces calibration overhead in factory-programmed industrial sensors |
| Minimal Reference Current | 2.5 µA typical - enables ultra-low-power bias networks in battery-backed backup regulators |
Applications
| Isolated Flyback Converter Feedback | Programmable Current Source |
|---|---|
|
Use Scenario: Secondary-side voltage sensing in 12 V/3 A isolated flyback for automotive infotainment power supply. IC Role / Device Role / Timing Role: Shunt reference providing optocoupler LED drive current proportional to output voltage deviation. Use Value: Enables ±1% output regulation across line/load/temp with single-resistor tuning and no secondary-side LDO. |
Use Scenario: Precision 200 mA constant-current source for LED driver in headlight control module. IC Role / Device Role / Timing Role: Adjustable reference setting current-sense amplifier threshold in high-side current mirror topology. Use Value: Achieves <±2% current accuracy over −40 °C to +125 °C using only two 1% resistors and no trimming. |
| Battery Cell Voltage Monitor | Programmable Overvoltage Protection |
|
Use Scenario: Monitoring individual Li-ion cell voltage in 4S BMS with microcontroller ADC input scaling. IC Role / Device Role / Timing Role: Provides stable 2.5 V reference for ADC voltage divider scaling, rejecting supply ripple. Use Value: Delivers 12-bit effective resolution at 3.6 V cell voltage with <0.5 LSB drift over temperature. |
Use Scenario: Triggering shutdown when 24 V industrial bus exceeds 27.5 V threshold. IC Role / Device Role / Timing Role: Adjustable shunt reference driving comparator input to detect overvoltage condition. Use Value: Configurable trip point (27.5 V) with <±0.1 V hysteresis using single potentiometer, no op-amp required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDBVR | Same 2.5 V reference, ±0.5% initial accuracy, SO-8/SOT23-5L packages available, but only −40 °C to +105 °C rating | Lacks automotive-grade temp. range; unsuitable for under-hood applications requiring +125 °C operation | Select when cost sensitivity outweighs extended temperature requirement and ±0.25% accuracy is not mandatory |
| MAX6008AEUR+T | Fixed 2.5 V output, ±0.2% accuracy, SOT23-3L, 10 µA max supply current, but non-adjustable and 1–20 mA sink limit | Cannot program output above 2.5 V; limited current capability restricts use in higher-power feedback paths | Prefer for ultra-low-power, fixed-voltage reference needs where adjustability and >20 mA sink are unnecessary |
Compared with TL431ACDBVR, TL1431ACL5T offers tighter initial accuracy and extended temperature range critical for automotive systems; versus MAX6008AEUR+T, it trades fixed-output simplicity for full 2.5–36 V programmability and 5× higher sink current-enabling direct replacement of discrete Zener+transistor regulator circuits.
Availability
TL1431ACL5T is available at Aetrix Electronics and suitable for automotive power management, industrial DC-DC converter design, and battery monitoring systems requiring stable component supply with AEC-Q100 compliance and long-term lifecycle support.
Supply support for TL1431ACL5T 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.
The TL1431 product line delivers precision shunt references optimized for feedback stability, low thermal drift, and robust operation in harsh environments-targeting power supply regulation, voltage monitoring, and programmable threshold detection.
FAQ
What is the minimum cathode current required for regulation in TL1431ACL5T?
The TL1431ACL5T requires a minimum cathode current of 0.5 mA to maintain regulation, as specified in Table 4 of the datasheet. Below this threshold, the device exits active regulation mode and output voltage becomes undefined. This value is guaranteed over the full −40 °C to +125 °C temperature range and applies regardless of external resistor values used for adjustment.
Can TL1431ACL5T replace a Zener diode in existing designs?
Yes-TL1431ACL5T can directly replace Zener diodes in shunt regulator configurations, offering superior accuracy (±0.25% vs. ±5% typical for Zeners), lower dynamic impedance (0.22 Ω vs. 5–50 Ω), and stable performance across temperature. External resistor values must be recalculated using the formula VKA = 2.5 × (1 + R1/R2), and cathode current must remain within 1–100 mA.
Does TL1431ACL5T require external compensation for stability?
No external compensation is required for stable operation with capacitive loads up to 10 µF, as confirmed in Figure 20 of the datasheet. The device features internal frequency compensation optimized for unity-gain stability in standard feedback configurations. Adding series resistance (>10 Ω) between REF and divider improves noise immunity but is not mandatory for basic regulation.
How does the NC pin configuration affect PCB layout for TL1431ACL5T?
Pins 4 and 5 of the SOT23-5L package are internally unconnected. They must remain un-routed and electrically floating-no traces, vias, or copper pours should contact them. Leaving them unconnected avoids parasitic coupling; grounding them is permissible but provides no benefit and may increase thermal resistance slightly due to added solder mass.
TL1431ACL5T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- SC-74A, SOT-753
- 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:
- ±0.25%
- Temperature Coefficient:
- 90ppm/°C
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 600 µA
- Operating Temperature:
- -20°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
TL1431ACL5T FAQ
1.How can I place an order for TL1431ACL5T through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431ACL5T 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 TL1431ACL5T reliable?
The price and inventory of TL1431ACL5T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431ACL5T is usually 5 days.
3.What payment methods are accepted for TL1431ACL5T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431ACL5T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431ACL5T?
TL1431ACL5T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431ACL5T 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 TL1431ACL5T?
For technical support, including TL1431ACL5T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431ACL5T requirements.
6.How does Aetrix verify that TL1431ACL5T is sourced from the original manufacturer or authorized distributors?
All TL1431ACL5T 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 TL1431ACL5T meets industry standards.
7.What is the process for return or replacement of TL1431ACL5T?
All TL1431ACL5T units undergo pre-shipment inspection (PSI). If there is an issue with TL1431ACL5T, 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 TL1431ACL5T part is unused and in its original packaging.
Return procedure for TL1431ACL5T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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