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Texas Instruments TL431ACLP-Z
- Part No.:
- TL431ACLP-Z
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
TL431ACLP-Z.pdf
- Description:
- IC REG LINEAR ADJ PREC SHUNT REG
- Quantity:
- Payment:
- Shipping:
Inventory:4,000
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Product details
Overview
TL431ACLP-Z from onsemi is a three-terminal programmable shunt voltage reference IC operating as a precision zener replacement with 2.495 V nominal reference voltage, ±1.0% initial tolerance, 50 ppm/°C typical temperature coefficient, 0.22 Ω typical dynamic impedance, and 1.0–100 mA sink current capability. It enables stable 2.5 V reference generation from 5 V logic supplies and serves as positive/negative voltage reference in power supply feedback loops.
For engineers reviewing the TL431ACLP-Z datasheet, TL431ACLP-Z pinout, TL431ACLP-Z application, or TL431ACLP-Z equivalent, this page delivers verified electrical specs, TO-92 LP package details, real-world use cases in crowbar protection and constant-current sinks, and validated alternative parts for design continuity.
Technical Context
The TL431ACLP-Z implements an internal 1.78 V bandgap reference with high-gain error amplifier and NPN output stage, configured as a shunt regulator where cathode current is controlled by the reference pin voltage relative to the internal threshold. Its operation requires only two external resistors to program output voltage from 2.5 V to 36 V.
Stability depends critically on load capacitance and cathode current: Figure 15 of the datasheet defines boundary conditions where ≥10 nF may cause instability at 7.5 mA cathode current, while <1 nF ensures stability across 1–100 mA range. The device exhibits low 20 pF input capacitance and 7.96 kHz dominant pole per its internal model.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V nominal; sets precise trip point for overvoltage detection or feedback loop setpoint |
| Initial Tolerance | ±1.0% at 25°C; determines absolute accuracy of programmed output without trimming |
| Temp Coefficient | 50 ppm/°C typical; contributes ≤3.5 mV drift over 0–70°C ambient range |
| Dynamic Impedance | 0.22 Ω typical; maintains regulation under fast load transients up to 100 mA |
| Sink Current Range | 1.0–100 mA continuous; supports direct drive of optocoupler LEDs or series-pass transistor bases |
| Max Cathode-Anode Voltage | 37 V; enables use in 24 V industrial systems with margin for surge events |
| Off-State Cathode Current | 20 nA max at 36 V; minimizes quiescent loss in battery-powered monitoring circuits |
Pinout & Package
TL431ACLP-Z is housed in a Pb-free TO-92 (Case 29) plastic package with 3 leads, optimized for through-hole mounting and thermal dissipation up to 0.70 W at 25°C ambient. Pin 1 is Reference, Pin 2 is Anode, Pin 3 is Cathode - no unused pins.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Reference) | High-impedance input sensing node | Compares external divider voltage to internal 2.495 V reference; draws ≤4 µA |
| 2 (Anode) | Current return path and ground reference | Connected to system ground or negative rail; completes shunt current path |
| 3 (Cathode) | Regulated output terminal | Sinks adjustable current to maintain Vref at pin 1; drives optocouplers or pass devices |
Key Features
| Feature | Design Value |
|---|---|
| Programmable output voltage | 2.5 V to 36 V via two-resistor divider; eliminates need for multiple fixed references |
| Low dynamic impedance | 0.22 Ω typical ensures <10 mV regulation error during 50 mA step loads |
| Wide operating current range | 1.0–100 mA sink capability supports both low-power monitoring and high-current feedback |
| Temperature-compensated reference | 50 ppm/°C TC enables stable performance across 0–70°C commercial temperature range |
| Low output noise | Sub-10 µVRMS noise in 10 Hz–10 kHz band preserves signal integrity in precision ADC references |
Applications
| Overvoltage Crowbar Protection | Optocoupler Feedback in SMPS |
|---|---|
Use Scenario: Detects DC bus overvoltage in industrial motor drives and triggers SCR-based shutdown. IC Role / Device Role / Timing Role: Precision voltage comparator with hysteresis-free trip point set by R1/R2 divider. Use Value: Enables ±1% overvoltage threshold accuracy at 24 V bus, reducing false trips vs. discrete zener solutions. | Use Scenario: Provides isolated feedback signal from secondary side to primary-side PWM controller in offline AC/DC converters. IC Role / Device Role / Timing Role: Shunt regulator driving PC817 optocoupler LED with 5–10 mA bias current. Use Value: Maintains ±1% output voltage regulation across line/load variations due to tight reference tolerance and low dynamic impedance. |
| Constant-Current Sink | Voltage Monitor with LED Indicator |
Use Scenario: Supplies stable 20 mA bias to laser diodes or sensor bridges in test equipment. IC Role / Device Role / Timing Role: Two-resistor configuration fixes cathode current independent of supply voltage fluctuations. Use Value: Delivers <±2% current accuracy from 5 V to 30 V input, eliminating need for op-amp-based current sources. | Use Scenario: Monitors 12 V automotive battery voltage and illuminates LED when within 11.8–12.6 V window. IC Role / Device Role / Timing Role: Dual-threshold comparator using separate upper/lower resistor dividers tied to same reference. Use Value: Achieves ±0.1 V window accuracy without trimming, leveraging matched resistor ratios and low TC reference. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BCLP | ±0.4% initial tolerance (vs. ±1.0%), same TO-92 LP package and 0–70°C rating | Higher accuracy required in precision power supply feedback or calibration circuits | Select TL431BCLP when reference accuracy dominates cost sensitivity |
| TL431ACLPG | Same ±1.0% tolerance but PDIP-8 package (Case 626), higher 1.10 W power dissipation | Through-hole designs requiring higher thermal margin or legacy board compatibility | Choose TL431ACLPG for prototyping or high-reliability industrial PCBs needing robust leadframe |
Compared with TL431BCLP and TL431ACLPG, TL431ACLP-Z offers optimal balance of cost, accuracy, and compact TO-92 footprint for volume consumer and industrial power supplies-where ±1% tolerance suffices and board space is constrained.
Availability
TL431ACLP-Z is available at Aetrix Electronics and suitable for power supply feedback, overvoltage protection, and constant-current source applications requiring stable component supply across automotive, industrial control, and consumer electronics programs.
Supply support for TL431ACLP-Z 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
onsemi (Nasdaq: ON) is a global semiconductor leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The TL431A/B Series was designed as a drop-in replacement for discrete zener diodes in shunt regulation, offering programmable voltage, tighter tolerance, and superior temperature stability for cost-sensitive power management systems.
FAQ
What is the reference voltage tolerance of TL431ACLP-Z at 25°C?
The TL431ACLP-Z has a ±1.0% initial reference voltage tolerance at 25°C, meaning its Vref falls between 2.470 V and 2.520 V under standard test conditions (VKA = Vref, IK = 10 mA). This specification is guaranteed per the TL431/D datasheet Rev. 38, Table on page 4, and applies specifically to the TL431ACLP-Z variant with LP (TO-92) packaging and C-grade temperature range (0°C to +70°C).
Can TL431ACLP-Z be used as a negative voltage reference?
Yes, TL431ACLP-Z can function as a negative voltage reference by connecting its anode to the negative rail and cathode to the circuit node being regulated. In this configuration, the reference pin remains at a potential 2.495 V above the anode, enabling stable negative output generation. The TL431ACLP-Z datasheet explicitly states it "can be used as either a positive or negative voltage reference," and Figure 21 shows a series-pass regulator implementation confirming bidirectional capability.
What is the minimum cathode current required for regulation in TL431ACLP-Z?
The TL431ACLP-Z requires a minimum cathode current of 0.5 mA to maintain regulation, with a typical value of 0.75 mA and maximum of 1.0 mA across its operating temperature range (0°C to +70°C). This parameter, labeled Imin in the Electrical Characteristics table on page 3 of the TL431/D datasheet, ensures the internal amplifier remains active and the output remains stable under light-load conditions.
How does the dynamic impedance of TL431ACLP-Z affect power supply ripple rejection?
The TL431ACLP-Z's typical dynamic impedance of 0.22 Ω directly determines its ability to suppress ripple on the cathode node: for every 10 mA of ripple current injected, output voltage variation is limited to 2.2 mV. This low ZKA enables effective ripple attenuation in optocoupler feedback paths of switching power supplies, contributing to tight output regulation as demonstrated in Figure 30's 50 mVpp ripple measurement at 1 A load.
Is TL431ACLP-Z RoHS compliant and lead-free?
Yes, TL431ACLP-Z is RoHS compliant and lead-free, as confirmed in the "Features" section of the TL431/D datasheet (Rev. 38, page 1): "These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS Compliant." The "-Z" suffix in TL431ACLP-Z explicitly denotes the Pb-free version per onsemi's ordering nomenclature defined on page 13, and the LP package (TO-92) uses matte tin lead finish.
TL431ACLP-Z Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- 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 ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL431ACLP-Z FAQ
1.How can I place an order for TL431ACLP-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431ACLP-Z 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 TL431ACLP-Z reliable?
The price and inventory of TL431ACLP-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431ACLP-Z is usually 5 days.
3.What payment methods are accepted for TL431ACLP-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431ACLP-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431ACLP-Z?
TL431ACLP-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431ACLP-Z 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 TL431ACLP-Z?
For technical support, including TL431ACLP-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431ACLP-Z requirements.
6.How does Aetrix verify that TL431ACLP-Z is sourced from the original manufacturer or authorized distributors?
All TL431ACLP-Z 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 TL431ACLP-Z meets industry standards.
7.What is the process for return or replacement of TL431ACLP-Z?
All TL431ACLP-Z units undergo pre-shipment inspection (PSI). If there is an issue with TL431ACLP-Z, 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 TL431ACLP-Z part is unused and in its original packaging.
Return procedure for TL431ACLP-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431ACLP-Z Tags
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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
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LM4040CYM3-4.1-TR
Microchip Technology
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LM4040EIM3-2.5/NOPB
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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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