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Diodes Incorporated AS431AKTR-E1
- Part No.:
- AS431AKTR-E1
- Manufacturer:
- Diodes Incorporated
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
AS431AKTR-E1.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,447
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Product details
Overview
AS431AKTR-E1 from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 0.5% reference voltage tolerance, 2.5V to 36V programmable output range, and guaranteed thermal stability from –40°C to +125°C. It replaces Zener diodes in switching power supplies, battery chargers, and precision voltage references, delivering low 0.15Ω dynamic impedance and 4.5mV typical reference voltage deviation over full temperature range.
For engineers reviewing the AS431AKTR-E1 datasheet, AS431AKTR-E1 pinout, AS431AKTR-E1 application, or AS431AKTR-E1 equivalent, key selection criteria include cathode current capability (1–100mA), low temperature coefficient (20ppm/°C typical), stable operation under capacitive loads, and SOT25 package compatibility with high-density PCB layouts.
Technical Context
The AS431AKTR-E1 implements a bandgap-based precision reference core with sharp turn-on characteristics and low output impedance, enabling accurate voltage regulation across wide load and temperature variations. Its internal architecture supports stable feedback in both shunt regulator and current-source configurations without external compensation.
It operates as a two-input, one-output active device: the REF pin senses voltage against an internal 2.5V基准, while the CATHODE sinks adjustable current to maintain regulation. The ANODE serves as the common return path, and the device requires no minimum load-only ≥0.4mA cathode current for regulation onset.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V ±0.5% - sets precise regulation threshold; enables accurate 5V, 12V, or custom output via external resistor divider |
| Cathode Current Range | 1 mA to 100 mA - supports direct regulation of medium-power rails or driving optocoupler LEDs in isolated SMPS feedback loops |
| Dynamic Impedance | 0.15 Ω typical - ensures minimal output voltage shift under fast load transients; critical for ripple-sensitive analog references |
| Tempco (ΔVREF) | 20 ppm/°C typical - guarantees ≤16 mV total drift from –40°C to +125°C; suitable for automotive under-hood applications |
| Operating Temperature | –40°C to +125°C - validated junction temperature range; enables use in industrial power supplies and embedded controllers |
| Max Cathode Voltage | 36 V - defines upper limit for regulated output setting; compatible with 24V system rails and flyback secondary-side designs |
| Off-State Cathode Current | 0.05 µA typical at 36V - ensures negligible quiescent loss when disabled; improves efficiency in standby-mode circuits |
Pinout & Package
SOT25 package: 5-pin surface-mount outline with exposed thermal pad; pin 2 internally connected to substrate and must be tied to ANODE or left floating per design requirements.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (REF) | Reference Input | Senses divided output voltage; connects to resistor divider midpoint to enable programmable regulation point |
| Pin 2 (NC) | No-Connect / Substrate Tie | Internally bonded to die substrate; must connect to ANODE node or remain unconnected-never driven high or low |
| Pin 3 (CATHODE) | Current Sink Output | Drains regulated current to ground or return rail; determines power dissipation and thermal design margin |
| Pin 4 (ANODE) | Common Return | Provides low-impedance return path for cathode current; ties to system ground or negative rail |
| Pin 5 (NC) | No-Connect | Unused terminal; electrically isolated; no connection required |
Key Features
| Feature | Design Value |
|---|---|
| Programmable Output Voltage | 2.5V to 36V via two-resistor divider-enables single BOM for multiple output voltages in multi-rail systems |
| Capacitive Load Stability | Stable with ≥100µF output capacitance-eliminates need for series damping resistors in bulk-capacitor filtering stages |
| Low Reference Current | 0.7 µA typical-reduces divider resistor power loss and improves accuracy in high-impedance sensing networks |
| High Sink Current Capacity | 100 mA continuous-supports direct drive of optocouplers, TL431 replacement, or error amplifier biasing |
| RoHS/Green Compliance | Fully lead-free and halogen/antimony-free-meets IPC-1752A Class 3 material declarations for automotive and industrial end equipment |
Applications
| Switching Power Supply Feedback | Battery Charger Voltage Regulation |
|---|---|
|
Use Scenario: Secondary-side voltage sensing in isolated flyback or forward converters using optocoupler-coupled feedback loop. IC Role / Device Role / Timing Role: Adjustable shunt reference providing precise error signal to optocoupler LED, enabling tight output voltage regulation. Use Value: 0.5% initial tolerance and 20ppm/°C tempco ensure ±1.5% total output variation over temperature-meeting USB PD and telecom power spec limits. |
Use Scenario: Constant-voltage stage control in Li-ion or lead-acid battery chargers with microcontroller supervision. IC Role / Device Role / Timing Role: Precision voltage clamp replacing Zener diode to set charge termination threshold with minimal drift. Use Value: 4.5mV typical ΔVREF over –40°C to +125°C prevents premature or delayed charge cutoff-extending battery cycle life. |
| Voltage Adapter Reference | Graphics Card VRM Monitoring |
|
Use Scenario: Low-cost AC/DC adapter with fixed 5V or 12V output requiring high-accuracy regulation without dedicated controller IC. IC Role / Device Role / Timing Role: Shunt regulator establishing stable reference for linear pass transistor or discrete PWM comparator. Use Value: 0.15Ω dynamic impedance maintains <10mV output deviation during 500mA load steps-improving adapter line/load regulation. |
Use Scenario: GPU voltage rail monitoring and fine-tuning in desktop graphics cards using analog feedback paths. IC Role / Device Role / Timing Role: Precision reference for ADC input scaling or DAC-controlled voltage trimming circuitry. Use Value: Low 0.05µA off-state current avoids loading sensitive sense nodes-preserving measurement accuracy in multi-rail telemetry systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDR | 2.5V reference, 2% tolerance, SOIC-8 package, higher 0.3Ω dynamic impedance | Larger footprint, lower accuracy, less stable under capacitive loads | Select when cost sensitivity outweighs precision and board space constraints |
| KA431AZTA | 2.5V reference, 2% tolerance, TO-92 package, 100°C max operating temperature | Through-hole mounting, limited thermal performance, no SMT compatibility | Select only for legacy through-hole designs where rework or thermal derating is acceptable |
Compared with TL431ACDR and KA431AZTA, AS431AKTR-E1 delivers tighter 0.5% tolerance, superior thermal stability to +125°C, lower dynamic impedance, and SOT25 packaging-making it optimal for high-density, high-reliability power management in modern industrial and computing platforms.
Availability
AS431AKTR-E1 is available at Aetrix Electronics and suitable for switching power supply feedback, battery charger voltage regulation, and voltage adapter reference applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for AS431AKTR-E1 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-performance power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.
The AS431 belongs to Diodes' precision reference product line, engineered for high-accuracy, thermally stable voltage regulation in power supply feedback, battery management, and instrumentation applications where Zener diodes fall short.
FAQ
What is the minimum cathode current required for AS431AKTR-E1 to regulate?
The AS431AKTR-E1 requires a minimum cathode current of 0.4 mA to initiate regulation, as specified in the Electrical Characteristics table under IKA(Min). This low startup threshold allows reliable operation even with high-value feedback resistors or low-power optocouplers, reducing overall system quiescent current.
Can AS431AKTR-E1 replace TL431 in existing designs?
Yes, AS431AKTR-E1 is functionally compatible with TL431 in most shunt regulator configurations, but requires verification of pin mapping (SOT25 vs SOIC-8) and thermal layout due to its lower dynamic impedance (0.15Ω vs ~0.3Ω) and tighter tolerance. No circuit redesign is needed if the SOT25 footprint is accommodated.
Does AS431AKTR-E1 require an external capacitor for stability?
No external capacitor is required for stability-the AS431AKTR-E1 remains stable with output capacitances up to 100µF, as confirmed in the Performance Characteristics section. Its internal compensation eliminates the need for series resistance or bypass caps typically used with TL431 derivatives.
What does the "E1" suffix indicate in AS431AKTR-E1?
The "E1" suffix denotes RoHS-compliant, lead-free construction with standard green molding compound, per Diodes Incorporated's packaging nomenclature. It corresponds to tape-and-reel packaging (3,000 units per reel), SOT25 package, and 0.5% reference voltage tolerance-confirmed in the Ordering Information table.
AS431AKTR-E1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- SC-74A, SOT-753
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±0.5%
- Temperature Coefficient:
- 20ppm/°C Typical
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
AS431AKTR-E1 FAQ
1.How can I place an order for AS431AKTR-E1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AS431AKTR-E1 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 AS431AKTR-E1 reliable?
The price and inventory of AS431AKTR-E1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AS431AKTR-E1 is usually 5 days.
3.What payment methods are accepted for AS431AKTR-E1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AS431AKTR-E1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AS431AKTR-E1?
AS431AKTR-E1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AS431AKTR-E1 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 AS431AKTR-E1?
For technical support, including AS431AKTR-E1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AS431AKTR-E1 requirements.
6.How does Aetrix verify that AS431AKTR-E1 is sourced from the original manufacturer or authorized distributors?
All AS431AKTR-E1 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 AS431AKTR-E1 meets industry standards.
7.What is the process for return or replacement of AS431AKTR-E1?
All AS431AKTR-E1 units undergo pre-shipment inspection (PSI). If there is an issue with AS431AKTR-E1, 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 AS431AKTR-E1 part is unused and in its original packaging.
Return procedure for AS431AKTR-E1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AS431AKTR-E1 Tags
-
TL431AIDBZR
Texas Instruments
-
TL431BQDBZR
Texas Instruments
-
AN431AN-ATRG1
Diodes Incorporated
-
LM4040CYM3-2.5-TR
Microchip Technology
-
LM4040CYM3-4.1-TR
Microchip Technology
-
LM4040EIM3-2.5/NOPB
Texas Instruments
-
AZ431LBNTR-G1
Diodes Incorporated
-
LM4040D20IDBZR
Texas Instruments
-
LM4041DIM3-ADJ/NOPB
Texas Instruments
-
LM4040DIM3X-2.5/NOPB
Texas Instruments
-
LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
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