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Texas Instruments TL431ACLPME3
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- Part No.:
- TL431ACLPME3
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
TL431ACLPME3.pdf
- Description:
- IC VREF SHUNT ADJ 1% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:20,388
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Product details
Overview
TL431ACLPME3 from Texas Instruments is a precision programmable shunt voltage reference IC with 1% initial tolerance at 25°C, adjustable output voltage from 2.47V to 36V, and operation across −40°C to 85°C. It delivers 0.2Ω typical dynamic impedance, 1–100mA sink-current capability, and low 6mV temperature drift (C-grade), widely used in feedback loops of isolated DC/DC converters and AC/DC power supplies.
For engineers reviewing the TL431ACLPME3 datasheet, TL431ACLPME3 pinout, TL431ACLPME3 application, or TL431ACLPME3 equivalent, key selection criteria include reference accuracy over temperature, cathode current range, dynamic impedance stability under load transients, and compatibility with standard optocoupler-based feedback topologies in industrial and computing power systems.
Technical Context
The TL431ACLPME3 implements a three-terminal adjustable shunt regulator architecture with an internal 2.495V bandgap reference, error amplifier, and NPN output stage. Its sharp turn-on characteristic and active output circuitry enable Zener diode replacement in closed-loop regulation without external compensation in many configurations.
It operates as a voltage-controlled current sink: the REF pin senses voltage relative to ANODE; when VREF exceeds 2.495V, the cathode sinks current to maintain regulation. The device requires ≥0.4mA minimum cathode current for stable operation and exhibits <0.5µA off-state leakage at 36V cathode voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.47–2.52V at 25°C (1% A-grade tolerance); sets precise feedback threshold in SMPS error amplifiers |
| Temp Range | −40°C to +85°C (I-grade); supports industrial ambient conditions without derating |
| Dynamic Impedance | 0.2Ω typical (≤0.5Ω max); ensures minimal output voltage shift during 1–100mA load steps |
| Cathode Current | 1–100mA continuous sink range; compatible with standard optocoupler LED drive requirements |
| Ref Input Current | 2–4µA typical; enables high-impedance resistor-divider networks (e.g., 10kΩ/10kΩ) with <0.1% error contribution |
| Temp Drift | ≤14mV over full −40°C to +85°C range; guarantees ≤0.05% output variation in critical feedback paths |
| Off-State Leakage | ≤0.5µA at 36V cathode; prevents unintended conduction in standby or fault modes |
Pinout & Package
SOT-23-3 (DBZ) package: 2.90mm × 1.30mm body, surface-mount, lead-free, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1: Cathode | Current sink output | Connects to primary-side optocoupler anode or regulation node; carries full error amplifier output current |
| Pin 2: Ref | Reference input | Senses voltage divider output; threshold is 2.495V ±1%; must be referenced to ANODE |
| Pin 3: Anode | Common return | Typically tied to system ground or negative rail; serves as voltage reference point for REF and Cathode |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable regulation | Output set from 2.47V to 36V using two external resistors-enables single BOM for multiple output voltages |
| Low dynamic impedance | 0.2Ω typical ensures <1mV output shift under 10mA transient loads-critical for tight-regulation SMPS |
| Sharp turn-on | Active output stage provides fast, clean regulation onset-eliminates Zener soft-start ambiguity in feedback loops |
| Low input bias current | 2–4µA REF pin current minimizes divider resistor self-heating and enables >1MΩ networks for ultra-low quiescent designs |
| High temp stability | 14mV max deviation over −40°C to +85°C-meets industrial-grade feedback accuracy requirements without calibration |
Applications
| Rack Server Power | Industrial AC/DC |
|---|---|
Use Scenario: Secondary-side voltage sensing in 48V-to-12V isolated buck converters for server VRMs. IC Role / Device Role / Timing Role: Shunt reference in optocoupler-coupled feedback loop; regulates output by modulating opto-LED current. Use Value: 1% initial accuracy and 14mV temp drift ensure ±1.5% total output tolerance across operating range-meets ATX12VO spec. | Use Scenario: Output voltage regulation in DIN-rail mounted 24V/48V AC/DC modules for PLC I/O power. IC Role / Device Role / Timing Role: Precision shunt reference driving PC817 optocoupler; closes control loop with <50µs response to line/load transients. Use Value: 0.2Ω dynamic impedance maintains regulation during 5A step-load events-reduces need for bulk capacitance by 30%. |
| AC Inverter Drives | Notebook PC Adapter |
Use Scenario: DC bus voltage monitoring and overvoltage protection in 3-phase motor drives. IC Role / Device Role / Timing Role: High-side shunt reference with resistor divider; triggers crowbar or shutdown when bus exceeds 400V. Use Value: 36V max cathode rating and 37V absolute max allow direct scaling to 400V bus via 100:1 divider-no level-shifting required. | Use Scenario: Constant-voltage regulation in 19V/3.42A GaN-based notebook adapters. IC Role / Device Role / Timing Role: Feedback reference for UCC28780 QR flyback controller; interfaces with TLVH431-level optocoupler. Use Value: 1–100mA sink range matches TL431-specific optocoupler CTR curves-ensures stable loop gain across production variance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431AILPME3 | Same SOT-23-3 package and pinout; tighter 0.5% initial tolerance (B-grade) | Required where ±0.5% output accuracy is mandated (e.g., medical power supplies) | Select when higher initial accuracy justifies cost premium and thermal drift budget allows |
| TL431ACDCKR | Same A-grade spec but in SC-70-3 (DCK) package; 2.20mm × 1.35mm footprint | Better suited for space-constrained portable designs where SOT-23-3 layout is unavailable | Choose for PCB area reduction without sacrificing electrical performance or thermal derating |
Compared with TL431AILPME3 and TL431ACDCKR, TL431ACLPME3 offers optimal balance of cost, accuracy, and manufacturability for industrial and computing power supplies-delivering 1% tolerance with proven SOT-23-3 reliability and thermal performance up to 85°C ambient.
Availability
TL431ACLPME3 is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC, and notebook PC adapter designs requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production lots.
Supply support for TL431ACLPME3 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 leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in precision reference and power control ICs.
The TL431 product line was designed specifically for high-reliability voltage regulation in isolated switching power supplies, offering programmable, Zener-replacement functionality with superior thermal stability and noise performance.
FAQ
What is the reference voltage tolerance of TL431ACLPME3 at 25°C?
The TL431ACLPME3 has a reference voltage tolerance of ±1% at 25°C, corresponding to a 2.47V–2.52V range. This A-grade specification is confirmed in Section 6.8 of the TI datasheet (SLVS543S) and applies specifically to the TL431AC variant in SOT-23-3 packaging. The TL431ACLPME3 maintains this tolerance across its rated operating temperature range.
What is the maximum cathode voltage rating for TL431ACLPME3?
The TL431ACLPME3 has an absolute maximum cathode voltage (VK A) rating of 37V, with recommended operation up to 36V. This value is specified in Section 6.1 (Absolute Maximum Ratings) of the TI datasheet and defines the upper limit for safe operation when the device is used as a shunt regulator. Exceeding 37V risks permanent damage.
Does TL431ACLPME3 require an external capacitor for stability?
The TL431ACLPME3 does not require an external capacitor for basic regulation stability, but capacitive loading on the cathode affects phase margin. Per Figure 6-16 and 6-18 in the datasheet, stability boundaries depend on cathode voltage and load capacitance-up to 1µF is generally safe at 10mA, while >10nF may require series resistance for robustness in high-gain feedback loops.
What is the minimum cathode current needed for regulation in TL431ACLPME3?
The TL431ACLPME3 requires a minimum cathode current (Imin) of 0.4mA to maintain regulation, with a typical value of 0.6mA at 25°C (Section 6.8). Below this threshold, the device exits regulation and cathode voltage rises uncontrollably. This parameter directly impacts optocoupler CTR selection and divider resistor sizing in feedback networks.
How does the temperature coefficient of TL431ACLPME3 compare to the B-grade version?
The TL431ACLPME3 (A-grade, I-temp) exhibits ≤14mV total deviation over −40°C to +85°C, whereas the B-grade TL431BILPME3 shows ≤34mV over the same range. Both share identical 2.495V nominal reference, but the A-grade's tighter initial tolerance improves overall accuracy-making TL431ACLPME3 preferable when drift budget is constrained but B-grade cost is unjustified.
TL431ACLPME3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Series:
- -
- Packaging:
- Cut Tape (CT)
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.495V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 600 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL431ACLPME3 FAQ
1.How can I place an order for TL431ACLPME3 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431ACLPME3 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 TL431ACLPME3 reliable?
The price and inventory of TL431ACLPME3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431ACLPME3 is usually 5 days.
3.What payment methods are accepted for TL431ACLPME3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431ACLPME3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431ACLPME3?
TL431ACLPME3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431ACLPME3 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 TL431ACLPME3?
For technical support, including TL431ACLPME3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431ACLPME3 requirements.
6.How does Aetrix verify that TL431ACLPME3 is sourced from the original manufacturer or authorized distributors?
All TL431ACLPME3 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 TL431ACLPME3 meets industry standards.
7.What is the process for return or replacement of TL431ACLPME3?
All TL431ACLPME3 units undergo pre-shipment inspection (PSI). If there is an issue with TL431ACLPME3, 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 TL431ACLPME3 part is unused and in its original packaging.
Return procedure for TL431ACLPME3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431ACLPME3 Tags
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TL431AIDBZR
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TL431BQDBZR
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LM4040CYM3-2.5-TR
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LM4040CYM3-4.1-TR
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LM4040EIM3-2.5/NOPB
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AZ431LBNTR-G1
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LM4040D20IDBZR
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LM4041DIM3-ADJ/NOPB
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LM4040DIM3X-2.5/NOPB
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LM4040DIM3-2.5/NOPB
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AZ431LANTR-G1
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