My Inquiry
My Account
Diodes Incorporated TL431AS-13
- Part No.:
- TL431AS-13
- Manufacturer:
- Diodes Incorporated
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TL431AS-13.pdf
- Description:
- IC VREF SHUNT ADJ 1% 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,091
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
TL431AS-13 from Diodes Incorporated is a precision adjustable shunt voltage regulator in SO-8 package, featuring 2.495 V reference voltage with ±1.0% initial tolerance at 25°C, 0.2 Ω typical dynamic output impedance, and 1 mA to 100 mA cathode current capability. It replaces discrete Zener diodes in feedback loops of isolated DC-DC converters and linear regulators requiring stable 2.5–36 V programmable references.
For engineers reviewing the TL431AS-13 datasheet, TL431AS-13 pinout, TL431AS-13 application, or TL431AS-13 equivalent, key selection criteria include reference voltage accuracy over –40°C to +125°C, low output noise (2.4 µV/√Hz at 10 kHz), stability with load capacitance up to 50 pF, and compatibility with optocoupler-based feedback networks in flyback power supplies.
Technical Context
The TL431AS-13 implements a bandgap-referenced error amplifier with internal NPN transistor output stage, operating as a 2-terminal shunt regulator when configured with external resistive divider. Its reference input (REF) senses voltage across R1/R2, and cathode (KA) sinks current to maintain VREF × (1 + R1/R2) at the regulated node.
It delivers 14–34 mV reference voltage deviation over –40°C to +125°C, exhibits –1.4 to –2.7 mV/V cathode voltage sensitivity (ΔVREF/ΔVKA), and maintains regulation down to 0.4 mA minimum cathode current-enabling operation in low-power standby modes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V ±1.0% at 25°C - sets precise threshold for feedback control loops |
| Output Impedance | 0.2 Ω typical - ensures minimal output voltage shift under load transients |
| Cathode Current Range | 1–100 mA - supports direct regulation of medium-current rails or driving optocoupler LEDs |
| Temperature Range | –40°C to +125°C - enables use in industrial and automotive under-hood environments |
| Dynamic Noise | 2.4 µV/√Hz at 10 kHz - reduces feedback loop jitter in high-accuracy SMPS designs |
| Stability Capacitance | ≤50 pF - allows direct connection to optocoupler CTR without phase compensation |
| Power Dissipation | 700 mW (SO-8) - permits >500 mW continuous dissipation at 25°C ambient with PCB copper pour |
Pinout & Package
TL431AS-13 is housed in an SO-8 surface-mount package (JEDEC MS-012AC) with standard 1.27 mm pitch, 4.9 mm × 6.0 mm body, and exposed thermal pad (not electrically connected). Pin 1 is ANODE, Pin 2 is REF, Pin 3 is CATHODE, Pins 4–8 are NC (no connect) and must be left floating or tied to ground per layout guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (ANODE) | Reference ground return | Common return path for REF and cathode current; connects to system GND or isolated secondary ground |
| 2 (REF) | Reference voltage sense input | High-impedance (1–4 µA) input that samples divided output voltage; determines regulation setpoint |
| 3 (CATHODE) | Current sink output | Sinks up to 100 mA to adjust feedback signal; drives optocoupler LED anode or shunt resistor |
| 4–8 (NC) | No electrical connection | Unused terminals; must remain unconnected to avoid parasitic coupling or thermal stress |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage range | 2.5 V to 36 V via two-resistor divider - eliminates need for multiple fixed-voltage references |
| Low temperature drift | 14–34 mV deviation over –40°C to +125°C - ensures <±0.5% output variation in wide-temperature applications |
| Lead-free & RoHS compliant | Fully halogen- and antimony-free "Green" construction - meets EU Directive 2011/65/EU without exemptions |
| High sink current capability | 100 mA continuous cathode current - directly drives optocoupler LEDs without external transistor buffering |
| Low reference input current | 1–4 µA at 25°C - minimizes divider resistor power loss and improves light-load efficiency |
Applications
| Isolated Flyback Power Supply | Programmable Linear Regulator |
|---|---|
|
Use Scenario: Secondary-side voltage sensing in 12 V/3 A offline flyback converter with optocoupler feedback. IC Role / Device Role / Timing Role: Shunt regulator providing precise 2.5 V reference to optocoupler LED cathode; regulates output by modulating LED current. Use Value: Enables ±1% output voltage accuracy across line/load/temperature while maintaining stability with ≤50 pF optocoupler capacitance. |
Use Scenario: Adjustable 5–24 V bench power supply using LM317 with external reference. IC Role / Device Role / Timing Role: Precision 2.495 V reference replacing Zener diode to set LM317 ADJ pin voltage. Use Value: Improves output voltage tolerance from ±2% (Zener-based) to ±0.5% and reduces temperature-induced drift by 3×. |
| Overvoltage Protection Circuit | Optocoupler Linearizer |
|
Use Scenario: 3.3 V rail monitoring in industrial PLC I/O module with latch-off on >3.6 V. IC Role / Device Role / Timing Role: Comparator-like function: REF pin biased to 3.6 V threshold; cathode triggers SCR gate when exceeded. Use Value: Achieves 15 mV trip-point hysteresis and sub-100 ns response time due to low output impedance and fast turn-on. |
Use Scenario: Feedback linearization in analog signal isolator using HCNR201 optocoupler. IC Role / Device Role / Timing Role: Reference source for matched photodiode biasing network to cancel CTR nonlinearity. Use Value: Reduces transfer function error from ±3% to ±0.25% across 0–10 V input range via precise 2.495 V bias point. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACD-13 (Texas Instruments) | Same 2.495 V ±1% reference, but SO-8 pinout differs: Pin 1 = REF, Pin 2 = ANODE, Pin 3 = CATHODE | Requires PCB layout revision; not drop-in compatible due to reversed ANODE/REF pins | Select only if redesigning board; verify REF/ANODE routing matches TI's pin 1–3 assignment |
| AS431ASTR-E1 (Diodes Inc.) | Same SO-8 package and pinout, but ±0.5% B-grade tolerance and higher 2.495 V ±0.5% accuracy | Delivers tighter output regulation in high-precision systems; increases cost by ~12% | Choose for medical or test equipment where <±0.3% total output error is required |
Compared with TL431ACD-13, TL431AS-13 offers native pin compatibility with Diodes' legacy designs and avoids layout rework; versus AS431ASTR-E1, it trades 0.5% reference tolerance for lower unit cost while retaining identical thermal and noise performance.
Availability
TL431AS-13 is available at Aetrix Electronics and suitable for isolated power supplies, programmable voltage references, overvoltage protection circuits, and optocoupler linearization requiring stable component supply across industrial, telecom, and embedded control applications.
Supply support for TL431AS-13 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 ICs, specializing in high-performance, energy-efficient components for power management, signal integrity, and protection.
The TL431 product line delivers precision shunt regulation for feedback control in switching and linear power supplies, targeting design-in reliability and long-term parametric stability across extended temperature ranges.
FAQ
What is the maximum cathode voltage rating for TL431AS-13?
The absolute maximum cathode-to-anode voltage (VKA) is 40 V. Operation above this level risks permanent device failure. For reliable long-term use, the recommended operating cathode voltage is limited to 36 V, matching the upper bound of its adjustable output range and ensuring margin against transient spikes.
Can TL431AS-13 operate with zero cathode current?
No. TL431AS-13 requires a minimum cathode current (IKA(MIN)) of 0.4–0.7 mA to maintain regulation. Below this threshold, the device exits active regulation and behaves as an open circuit; designers must ensure external biasing provides ≥1 mA under all operating conditions, including light-load or standby modes.
How does the SO-8 package of TL431AS-13 improve thermal performance over SOT23?
The SO-8 package provides 700 mW power dissipation (vs. 330 mW for SOT23) due to lower thermal resistance (θJA = 70°C/W vs. 380°C/W) and larger copper area for heat spreading. This enables sustained 100 mA cathode current at 25°C ambient without derating, critical for high-power optocoupler drive or shunt regulation.
Is TL431AS-13 compatible with lead-free reflow soldering profiles?
Yes. TL431AS-13 is fully RoHS-compliant and rated for standard lead-free reflow profiles with peak temperature up to 260°C (per JEDEC J-STD-020). Its MSL level is 1 (unlimited floor life), and the SO-8 package withstands three reflow cycles without degradation to electrical parameters or mechanical integrity.
TL431AS-13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- 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:
- 700 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
TL431AS-13 FAQ
1.How can I place an order for TL431AS-13 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431AS-13 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 TL431AS-13 reliable?
The price and inventory of TL431AS-13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431AS-13 is usually 5 days.
3.What payment methods are accepted for TL431AS-13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431AS-13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431AS-13?
TL431AS-13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431AS-13 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 TL431AS-13?
For technical support, including TL431AS-13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431AS-13 requirements.
6.How does Aetrix verify that TL431AS-13 is sourced from the original manufacturer or authorized distributors?
All TL431AS-13 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 TL431AS-13 meets industry standards.
7.What is the process for return or replacement of TL431AS-13?
All TL431AS-13 units undergo pre-shipment inspection (PSI). If there is an issue with TL431AS-13, 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 TL431AS-13 part is unused and in its original packaging.
Return procedure for TL431AS-13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431AS-13 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…
