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Diodes Incorporated AS431BKTR-E1
- Part No.:
- AS431BKTR-E1
- Manufacturer:
- Diodes Incorporated
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
AS431BKTR-E1.pdf
- Description:
- IC VREF SHUNT ADJ 1% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,125
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Product details
Overview
AS431BKTR-E1 from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 1.0% reference voltage tolerance, 2.5V to 36V programmable output, 0.15Ω typical dynamic impedance, and -40°C to +125°C operating range-used as a Zener diode replacement in switching power supplies, battery chargers, and precision voltage references.
For engineers reviewing the AS431BKTR-E1 datasheet, AS431BKTR-E1 pinout, AS431BKTR-E1 application, or AS431BKTR-E1 equivalent, this page delivers verified electrical specs, SOT25 package terminal mapping, thermal resistance (135.9°C/W), cathode current regulation range (1–100mA), and real-world use cases including PWM converter reference and high-current shunt regulation.
Technical Context
The AS431BKTR-E1 implements a bandgap-based reference core with sharp turn-on characteristics and low temperature coefficient (20 ppm/°C typical), enabling stable regulation across wide ambient and load variations. Its internal architecture supports direct feedback via external resistor dividers without requiring additional compensation components.
It operates as a two-quadrant device: sinking cathode current from 1mA to 100mA while maintaining reference voltage accuracy under capacitive loads up to 100µF, with no oscillation observed at VKA = 5V, 10V, or 15V per stability boundary testing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VREF) | 2.500 V ±1.0% - sets precise regulation threshold for external resistor divider networks |
| Output Voltage Range | 2.5V to 36V - programmable via external resistors, supporting wide-range DC-DC feedback |
| Dynamic Impedance (ZKA) | 0.15 Ω typical - ensures minimal output voltage deviation under fast load transients |
| Cathode Current Range | 1 mA to 100 mA - defines usable sink current window for stable regulation and thermal management |
| Temperature Coefficient | 20 ppm/°C typical - guarantees <±16 mV total drift over -40°C to +125°C operating range |
| Junction-to-Case Thermal Resistance | 135.9 °C/W - enables thermal design for SOT25 package at up to 370 mW power dissipation |
| Operating Ambient Temperature | -40°C to +125°C - qualified for industrial and automotive under-hood applications |
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 open per datasheet Note 4.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | REF | Reference input node - connects to resistor divider midpoint to set output voltage |
| 2 | ANODE | Anode terminal - electrically tied to substrate; must be connected to system ground or left floating |
| 3 | CATHODE | Cathode output - sinks regulated current into external load or feedback network |
| 4 | NC | No-connect - internal die bond wire stub; no electrical function |
| 5 | ANODE | Second anode terminal - redundant connection to same internal node as Pin 2 |
Key Features
| Feature | Design Value |
|---|---|
| Programmable output voltage | 2.5V–36V via two-resistor divider - eliminates need for multiple fixed-voltage references |
| Low temperature drift | 4.5 mV typical full-range deviation - reduces calibration burden in precision analog systems |
| Capacitive load stability | Stable with ≥100 µF output capacitance - simplifies EMI filtering and transient response design |
| High sink current capability | 100 mA max cathode current - supports direct drive of optocouplers or error amplifiers in isolated SMPS |
| Lead-free & Green compliance | RoHS 3 and halogen/antimony-free - meets IPC-1752A material declaration requirements |
Applications
| Charger Feedback Reference | Switching Power Supply Shunt Regulator |
|---|---|
Use Scenario: Used in constant-voltage/constant-current lithium-ion charger IC feedback loop to maintain ±1% output accuracy across temperature. IC Role / Device Role / Timing Role: Precision shunt reference providing stable 2.5V threshold for error amplifier comparison. Use Value: Enables tight output regulation without trimming, reducing BOM count and production test time. |
Use Scenario: Implements secondary-side voltage regulation in flyback converters with optocoupler isolation. IC Role / Device Role / Timing Role: Adjustable shunt regulator setting feedback voltage for TL431-compatible control ICs. Use Value: Delivers 0.15Ω dynamic impedance to suppress noise coupling into primary-side controller. |
| Precision 5V 1A Regulator | PWM Converter Reference |
Use Scenario: Configured as 5.0V reference in linear post-regulator stage for FPGA core supply. IC Role / Device Role / Timing Role: Programmable shunt element defining output voltage via R1/R2 divider (R1=10kΩ, R2=10kΩ). Use Value: Achieves <±10 mV output variation over -40°C to +85°C, eliminating need for external trim pot. |
Use Scenario: Provides stable reference for UC384x-series PWM controllers in AC-DC adapters. IC Role / Device Role / Timing Role: Cathode-connected to COMP pin; REF tied to feedback divider to set duty cycle threshold. Use Value: 20 ppm/°C tempco ensures consistent PWM frequency and duty cycle across thermal cycling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBVR | 0.5% VREF tolerance, 2.495V nominal, SOT23-3 package, higher 0.22Ω ZKA | Requires PCB redesign for 3-pin vs. 5-pin layout; lower tempco but reduced sink current (100mA vs. 100mA same) | Select when tighter initial accuracy is prioritized over thermal robustness in compact layouts |
| AS431AKTR-G1 | Same die, 0.5% VREF tolerance, SOT25 package, green/halogen-free molding compound | Identical pinout and thermal performance; differs only in marking ID and RoHS compliance level | Choose for new designs requiring halogen-free qualification and full RoHS 3 compliance |
Compared with TL431BIDBVR, AS431BKTR-E1 trades 0.5% initial accuracy for superior thermal stability margin and identical SOT25 footprint compatibility; versus AS431AKTR-G1, it offers cost-optimized lead-free compliance without halogen-free constraints.
Availability
AS431BKTR-E1 is available at Aetrix Electronics and suitable for switching power supplies, battery chargers, and precision voltage reference circuits requiring stable component supply across industrial temperature ranges and long-lifecycle programs.
Supply support for AS431BKTR-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-reliability power management, signal integrity, and protection solutions for industrial and consumer markets.
The AS431 belongs to Diodes' precision reference product line, engineered for high-stability shunt regulation in space-constrained, thermally demanding power conversion systems where Zener diode limitations necessitate active reference alternatives.
FAQ
What is the minimum cathode current required for regulation in AS431BKTR-E1?
The AS431BKTR-E1 requires a minimum cathode current of 0.4 mA to maintain regulation, with typical operation starting at 1.0 mA per datasheet Section "Electrical Characteristics." This low turn-on threshold allows reliable startup in high-impedance feedback networks and low-power standby modes.
Can AS431BKTR-E1 replace TL431 in existing designs?
Yes, AS431BKTR-E1 is functionally compatible with TL431 in most applications, but pinout differs: TL431 uses 3-pin SOT23 while AS431BKTR-E1 uses 5-pin SOT25. Direct replacement requires PCB layout revision; however, its identical electrical behavior and improved thermal resistance make it a drop-in functional upgrade where board space permits.
What is the maximum cathode voltage rating for AS431BKTR-E1?
The absolute maximum cathode-to-anode voltage (VKA) is 40 V, with recommended operating limit at 36 V. Exceeding 36 V risks exceeding safe operating area limits and may trigger thermal runaway under high sink current conditions, especially above 85°C ambient.
Does AS431BKTR-E1 require external compensation for stability?
No external compensation is required. The AS431BKTR-E1 remains stable with output capacitance up to 100 µF, as confirmed by stability boundary testing in the datasheet. Its internal compensation supports direct use with ceramic or electrolytic bulk capacitors in SMPS feedback loops without added RC networks.
AS431BKTR-E1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- SC-74A, SOT-753
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Not For New Designs
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±1%
- 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
AS431BKTR-E1 FAQ
1.How can I place an order for AS431BKTR-E1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AS431BKTR-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 AS431BKTR-E1 reliable?
The price and inventory of AS431BKTR-E1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AS431BKTR-E1 is usually 5 days.
3.What payment methods are accepted for AS431BKTR-E1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AS431BKTR-E1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AS431BKTR-E1?
AS431BKTR-E1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AS431BKTR-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 AS431BKTR-E1?
For technical support, including AS431BKTR-E1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AS431BKTR-E1 requirements.
6.How does Aetrix verify that AS431BKTR-E1 is sourced from the original manufacturer or authorized distributors?
All AS431BKTR-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 AS431BKTR-E1 meets industry standards.
7.What is the process for return or replacement of AS431BKTR-E1?
All AS431BKTR-E1 units undergo pre-shipment inspection (PSI). If there is an issue with AS431BKTR-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 AS431BKTR-E1 part is unused and in its original packaging.
Return procedure for AS431BKTR-E1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AS431BKTR-E1 Tags
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TL431AIDBZR
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TL431BQDBZR
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AN431AN-ATRG1
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LM4040EIM3-2.5/NOPB
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AZ431LBNTR-G1
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LM4040DIM3X-2.5/NOPB
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AZ431LANTR-G1
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