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Diodes Incorporated AS431ARTR-E1
- Part No.:
- AS431ARTR-E1
- Manufacturer:
- Diodes Incorporated
- Category:
- Voltage Reference
- Package:
- TO-243AA
- Datasheet:
-
AS431ARTR-E1.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT89-3
- Quantity:
- Payment:
- Shipping:
Inventory:846
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Product details
Overview
AS431ARTR-E1 from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 0.5% reference voltage tolerance, 2.5V to 36V programmable output, 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 deviation over full temperature range.
For engineers reviewing the AS431ARTR-E1 datasheet, AS431ARTR-E1 pinout, AS431ARTR-E1 application, or AS431ARTR-E1 equivalent, key selection criteria include cathode current capability (1–100mA), low temperature coefficient (20ppm/°C typical), high capacitive load stability, and SOT89 package thermal resistance (29.8°C/W).
Technical Context
The AS431ARTR-E1 operates as a two-input, one-output shunt reference: REF pin senses internal 2.5V bandgap, while cathode-anode path sinks adjustable current to maintain regulated voltage across an external resistor divider. Its sharp turn-on and low output impedance enable stable feedback in isolated DC-DC converters and PWM controllers.
It functions without external compensation under ≤100µF capacitive loads and maintains regulation with cathode voltages up to 36V. The device's low 0.7µA typical reference current and <1.2µA temperature drift minimize bias network error in high-impedance voltage-setting configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500V ±0.5% - sets precise regulation point for external resistor divider networks |
| Output Voltage Range | 2.5V to 36V - programmable via external resistive divider without additional components |
| Cathode Current Range | 1mA to 100mA - supports both low-power biasing and high-current shunt regulation |
| Temp Coefficient | 20ppm/°C typical - ensures <±16mV total drift over –40°C to +125°C operating range |
| Dynamic Impedance | 0.15Ω typical - provides stiff reference node against load transients in feedback loops |
| Thermal Resistance θJC | 29.8°C/W (SOT89) - enables 1W+ power dissipation with moderate heatsinking |
| Operating Temp | –40°C to +125°C - qualified for industrial and automotive under-hood environments |
Pinout & Package
AS431ARTR-E1 is packaged in RoHS-compliant, lead-free SOT89 (Option 1) with exposed thermal pad. Pin 1 = REF, Pin 2 = CATHODE, Pin 3 = ANODE. Pin 2 connects directly to the die substrate and must be electrically tied to the cathode node for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (REF) | Reference Input | Senses internal 2.5V bandgap; connected to voltage divider midpoint for output programming |
| Pin 2 (CATHODE) | Current Sink Output | Carries regulated shunt current; bonded to thermal pad for heat dissipation |
| Pin 3 (ANODE) | Return Path | Completes current path to ground or negative rail; ties to system common |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Reference | 2.5V to 36V set by two external resistors - eliminates need for multiple fixed-voltage references |
| Capacitive Load Stability | Stable with ≥100µF output capacitance - simplifies EMI filtering in switcher feedback paths |
| Low Reference Current | 0.7µA typical at 25°C - reduces divider power loss and improves high-impedance setting accuracy |
| High Temp Stability | 4.5mV max deviation over –40°C to +125°C - enables single-part qualification across extended industrial range |
| Green Packaging | SOT89 with halogen/antimony-free molding compound - meets IPC-1752A Class 3 environmental compliance |
Applications
| Switching Power Supply | Battery Charger |
|---|---|
Use Scenario: Secondary-side voltage sensing in isolated flyback or forward converters. IC Role / Device Role / Timing Role: Precision shunt reference in optocoupler feedback loop to regulate output voltage within ±1%. Use Value: 20ppm/°C tempco and 0.15Ω impedance ensure tight cross-regulation and minimal load/line transient deviation. |
Use Scenario: Constant-voltage stage control in multi-cell Li-ion charger ICs. IC Role / Device Role / Timing Role: External reference for charger controller ADC or error amplifier input. Use Value: Low 0.7µA reference current avoids loading high-resistance divider networks used in portable designs. |
| Voltage Adapter | Graphic Card VRM |
Use Scenario: Step-down DC adapter for legacy 5V/3.3V peripherals powered from 12V rails. IC Role / Device Role / Timing Role: Shunt regulator in linear post-regulator stage for noise-sensitive analog circuitry. Use Value: Low output noise and sharp turn-on prevent audible switching artifacts in audio subsystems. |
Use Scenario: Remote sensing reference for GPU core voltage (VDDC) tracking in high-current VRMs. IC Role / Device Role / Timing Role: Precision feedback node for multiphase buck controller reference input. Use Value: SOT89 thermal performance (29.8°C/W) sustains 1.5W dissipation during VRM transient overload events. |
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 ±0.5%, 36V max cathode voltage, but higher 25ppm/°C tempco and 0.22Ω impedance | Less stable under wide-temp industrial operation; requires larger compensation capacitor | Prefer TL431ACDR only when legacy footprint compatibility with SOIC-8 is required |
| KA431AZTA | 2.5V ±2.2%, 36V max, TO92 package, 100ppm/°C tempco, no green/RoHS compliance | Not suitable for automotive or high-reliability industrial use due to wider tolerance and Pb content | Select KA431AZTA only for cost-sensitive consumer applications with relaxed accuracy requirements |
Compared with TL431ACDR and KA431AZTA, AS431ARTR-E1 delivers tighter initial tolerance, lower thermal drift, superior dynamic impedance, and full RoHS/Green compliance - making it optimal for next-generation power management where precision, reliability, and regulatory alignment are critical.
Availability
AS431ARTR-E1 is available at Aetrix Electronics and suitable for switching power supply design, battery charging systems, and precision voltage reference circuits requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for AS431ARTR-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, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and the Americas.
The AS431 belongs to Diodes' precision reference product line, engineered specifically for high-stability shunt regulation in power conversion, battery management, and industrial control systems where Zener replacement with improved accuracy and thermal behavior is required.
FAQ
What is the minimum cathode current required for regulation in AS431ARTR-E1?
The AS431ARTR-E1 requires a minimum cathode current of 0.4mA to maintain regulation, verified per datasheet Test Circuit 4 at VKA = VREF. This low threshold enables reliable startup and regulation even with high-value resistor dividers or light-load conditions in battery-powered systems.
Can AS431ARTR-E1 replace a standard Zener diode directly in existing designs?
Yes - AS431ARTR-E1 is a functional drop-in replacement for Zener diodes rated 2.5V–36V, using identical three-terminal topology (anode/cathode/ref). Unlike Zeners, it requires no minimum current for stable voltage and exhibits far lower dynamic impedance and temperature drift, improving overall system accuracy.
Does AS431ARTR-E1 require external compensation for stability?
No external compensation is needed. The AS431ARTR-E1 remains stable with output capacitances up to 100µF, as confirmed in datasheet Figure 10 (Stability Boundary Conditions vs. Load Capacitance). This eliminates compensation networks in most SMPS feedback implementations.
What is the maximum power dissipation for AS431ARTR-E1 in SOT89 package?
In SOT89 package, AS431ARTR-E1 has a junction-to-case thermal resistance of 29.8°C/W and absolute maximum junction temperature of +150°C. At +85°C ambient, maximum continuous power dissipation is approximately 2.18W - validated by derating curves in DS36599 Rev. 4-2, page 4.
AS431ARTR-E1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- TO-243AA
- 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:
- ±0.5%
- 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-89-3
AS431ARTR-E1 FAQ
1.How can I place an order for AS431ARTR-E1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AS431ARTR-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 AS431ARTR-E1 reliable?
The price and inventory of AS431ARTR-E1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AS431ARTR-E1 is usually 5 days.
3.What payment methods are accepted for AS431ARTR-E1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AS431ARTR-E1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AS431ARTR-E1?
AS431ARTR-E1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AS431ARTR-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 AS431ARTR-E1?
For technical support, including AS431ARTR-E1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AS431ARTR-E1 requirements.
6.How does Aetrix verify that AS431ARTR-E1 is sourced from the original manufacturer or authorized distributors?
All AS431ARTR-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 AS431ARTR-E1 meets industry standards.
7.What is the process for return or replacement of AS431ARTR-E1?
All AS431ARTR-E1 units undergo pre-shipment inspection (PSI). If there is an issue with AS431ARTR-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 AS431ARTR-E1 part is unused and in its original packaging.
Return procedure for AS431ARTR-E1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AS431ARTR-E1 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
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LM4040EIM3-2.5/NOPB
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AZ431LBNTR-G1
Diodes Incorporated
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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
Diodes Incorporated
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