My Inquiry
My Account
Diodes Incorporated AS431BRTR-E1
- Part No.:
- AS431BRTR-E1
- Manufacturer:
- Diodes Incorporated
- Category:
- Voltage Reference
- Package:
- TO-243AA
- Datasheet:
-
AS431BRTR-E1.pdf
- Description:
- IC VREF SHUNT ADJ 1% SOT89-3
- Quantity:
- Payment:
- Shipping:
Inventory:1,000
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
AS431BRTR-E1 from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 1.0% reference voltage tolerance, 2.5V to 36V programmable output, 1mA–100mA sink current capability, and thermal stability across –40°C to +125°C. It replaces Zener diodes in switching power supplies, battery chargers, and precision voltage references where low temperature coefficient (20 ppm/°C typical) and sharp turn-on are required.
For engineers reviewing the AS431BRTR-E1 datasheet, AS431BRTR-E1 pinout, AS431BRTR-E1 application, or AS431BRTR-E1 equivalent, key selection criteria include cathode voltage range (up to 36V), dynamic impedance (0.15Ω typical), reference current (0.7–4 µA), off-state cathode leakage (<1.0 µA), and SOT89 package thermal resistance (29.8°C/W).
Technical Context
The AS431BRTR-E1 implements a bandgap-based reference core with internal error amplifier and output stage optimized for shunt regulation. Its functional block includes a precision 2.5V reference, high-gain transconductance amplifier, and cathode driver capable of sinking up to 100mA while maintaining <0.5Ω dynamic impedance.
It operates in closed-loop configuration with external resistive divider between cathode and reference pin, enabling precise output voltage setting. Stability is maintained under capacitive loads up to 100µF without oscillation, verified across cathode voltages from 3.5V to 15V at 25°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V ±1.0% - sets base accuracy for all output configurations |
| Output Voltage Range | 2.5 V to 36 V - programmable via external resistor divider, not internally fixed |
| Cathode Current Range | 1 mA to 100 mA - defines minimum regulation threshold and maximum sink capacity |
| Temperature Coefficient | 20 ppm/°C typical - ensures ≤16 mV drift over –40°C to +125°C full range |
| Dynamic Impedance | 0.15 Ω typical - maintains tight regulation under fast load transients |
| Off-State Cathode Current | 0.05–1.0 µA at 36V - enables ultra-low quiescent loss in standby mode |
| Operating Temperature | –40°C to +125°C - supports industrial and automotive under-hood environments |
Pinout & Package
SOT89-3 package with exposed thermal pad (Option 1 layout); 3-pin surface-mount outline measuring 4.40×2.60×1.60 mm; thermal resistance θJC = 29.8°C/W enables 1W+ dissipation with proper PCB copper area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Anode) | Current return path | Connected to system ground or low-side return; must be tied to GND for stable operation |
| 2 (Cathode) | Regulated output node | Sinks current to maintain set voltage; connects to feedback point of DC-DC converter or charger IC |
| 3 (Ref) | Reference input | High-impedance node (0.7–4 µA bias) that senses divided output voltage; sets regulation point |
Key Features
| Feature | Design Value |
|---|---|
| Programmable output voltage | 2.5V–36V via two-resistor divider - eliminates need for multiple Zener part numbers |
| Capacitive load stability | No oscillation with ≥100 µF output capacitance - simplifies EMI filter design in SMPS |
| Low temperature deviation | 4.5 mV typical drift over full range - enables ±0.2% system-level voltage accuracy |
| Lead-free & green compliance | RoHS 3 / halogen-antimony free - meets IPC-1752A material declaration requirements |
| High sink current density | 100 mA in SOT89 - supports >5W shunt regulation without heatsink |
Applications
| Switching Power Supply | Battery Charger |
|---|---|
|
Use Scenario: Secondary-side voltage sensing in isolated flyback converters delivering 12V/2A output. IC Role / Device Role / Timing Role: Precision shunt reference providing feedback to optocoupler-driven PWM controller. Use Value: Enables ±1% output regulation across line/load/temperature with single external resistor pair. |
Use Scenario: Constant-voltage stage in 5V/2A USB PD wall adapter with CC/CV control loop. IC Role / Device Role / Timing Role: Adjustable reference setting CV threshold; interfaces with primary-side controller via optocoupler. Use Value: Replaces discrete Zener + transistor network, reducing BOM count by 3 components and improving thermal tracking. |
| Voltage Adapter | Graphic Card VRM Reference |
|
Use Scenario: 3.3V-to-2.5V level-shifting supply for legacy I/O on modern SoC evaluation boards. IC Role / Device Role / Timing Role: Shunt regulator configured as active voltage dropper with series resistor. Use Value: Delivers stable 2.5V at 500mA with <10mV ripple, eliminating need for LDO in space-constrained layouts. |
Use Scenario: Precision 1.2V reference for GPU core voltage sense in PCIe graphics card VRM. IC Role / Device Role / Timing Role: High-stability reference input to multiphase controller's remote sensing amplifier. Use Value: Maintains <±3mV reference accuracy over –25°C to +95°C GPU junction range, ensuring ±0.5% VDDQ tolerance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBZR | 0.5% initial tolerance, higher 0.2Ω typical ZKA, 125°C max TA | Preferred in cost-sensitive consumer SMPS where tighter initial accuracy offsets slightly lower thermal margin | Select when ±0.5% reference accuracy is mandatory and SOT23 footprint is acceptable |
| KA431AZTA | 1.0% tolerance, TO92 through-hole, 81.9°C/W θJC, 770mW PD | Used in legacy industrial power supplies requiring manual assembly or high-reliability through-hole mounting | Choose only for through-hole designs needing RoHS-compliant TO92; not drop-in for SOT89 PCBs |
Compared with TL431BIDBZR, AS431BRTR-E1 offers superior thermal performance (29.8 vs. 135.9°C/W) and wider operating temperature range (–40°C to +125°C vs. –40°C to +125°C same, but higher sustained power capability). Against KA431AZTA, it provides surface-mount compatibility, lower profile, and improved dynamic impedance for faster transient response.
Availability
AS431BRTR-E1 is available at Aetrix Electronics and suitable for switching power supplies, battery chargers, and precision voltage reference circuits requiring stable component supply, long-term lifecycle support, and RoHS 3 compliance.
Supply support for AS431BRTR-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 centers across Asia and manufacturing in China, Taiwan, and Malaysia.
The AS431 belongs to Diodes' precision reference product line, engineered specifically for high-accuracy shunt regulation in power conversion systems where Zener replacement, thermal stability, and compact packaging are critical.
FAQ
What is the minimum cathode current required for regulation in AS431BRTR-E1?
The AS431BRTR-E1 requires a minimum cathode current of 0.4 mA to maintain regulation, with typical value of 1.0 mA at 25°C. This ensures stable operation even under light-load conditions in battery-powered adapters and standby power rails.
Can AS431BRTR-E1 replace a standard Zener diode directly in existing designs?
Yes - AS431BRTR-E1 can directly replace Zener diodes rated 2.5V–36V using identical anode/cathode connections, but requires adding a 2-resistor divider from cathode to reference pin to set output voltage. No additional biasing or compensation is needed.
Does AS431BRTR-E1 require an external capacitor for stability?
No external capacitor is required for basic stability. The device remains oscillation-free with output capacitances up to 100 µF across cathode-to-ground, as confirmed in the datasheet's stability boundary plots for VKA = 5V, 10V, and 15V.
What is the thermal performance difference between SOT89 and SOT23 packages for AS431?
SOT89 offers θJC = 29.8°C/W versus SOT23's 135.9°C/W - a 4.5× improvement. This allows AS431BRTR-E1 in SOT89 to dissipate ~1.1W continuously with 2 cm² of 2-oz copper, while SOT23 is limited to ~250 mW under identical conditions.
AS431BRTR-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:
- ±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-89-3
AS431BRTR-E1 FAQ
1.How can I place an order for AS431BRTR-E1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AS431BRTR-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 AS431BRTR-E1 reliable?
The price and inventory of AS431BRTR-E1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AS431BRTR-E1 is usually 5 days.
3.What payment methods are accepted for AS431BRTR-E1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AS431BRTR-E1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AS431BRTR-E1?
AS431BRTR-E1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AS431BRTR-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 AS431BRTR-E1?
For technical support, including AS431BRTR-E1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AS431BRTR-E1 requirements.
6.How does Aetrix verify that AS431BRTR-E1 is sourced from the original manufacturer or authorized distributors?
All AS431BRTR-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 AS431BRTR-E1 meets industry standards.
7.What is the process for return or replacement of AS431BRTR-E1?
All AS431BRTR-E1 units undergo pre-shipment inspection (PSI). If there is an issue with AS431BRTR-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 AS431BRTR-E1 part is unused and in its original packaging.
Return procedure for AS431BRTR-E1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AS431BRTR-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
Tech Hub
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
LDO regulator guide covering low dropout voltage, power dissipation, thermal design, PSRR, output noise, capacitor stability, adjustable LDO circuits, LDO vs buck converter and datasheet selection chec…
Conditional Access Module guide covering CAM meaning, CI/CI+ interface, smart card authorization, DVB security workflow, TV and set-top box compatibility, internal electronics, ESD protection, connecto…
Guide to electronic component obsolescence covering EOL risk, PCN/PDN notices, last-time buy planning, replacement options, form-fit-function validation, counterfeit risk and BOM lifecycle management.
18650 battery guide covering lithium-ion cell basics, 3.6V/3.7V voltage, 4.2V charging, mAh and Wh capacity, protected cells, chargers, BMS, series-parallel packs, holders, welding and sourcing checks.…
Hall effect sensor guide covering working principle, linear and digital sensors, Arduino circuits, current sensing, speed detection, automotive applications, A3144 examples, signal filtering and datash…
Product Change Notification guide for electronic components, covering PCN meaning, PCN vs PDN/EOL, common change types, risk levels, form-fit-function review, engineering validation, BOM control, LTB/L…
A practical guide to blend door actuators, covering HVAC function, symptoms, location, AC and heater issues, reset and calibration, replacement cost, electrical diagnosis, compatibility checks, and rep…
