My Inquiry
My Account
Diodes Incorporated LA431NHPA
- Part No.:
- LA431NHPA
- Manufacturer:
- Diodes Incorporated
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
LA431NHPA.pdf
- Description:
- IC VREF SHUNT ADJ TO92
- Quantity:
- Payment:
- Shipping:
Inventory:4,441
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LA431NHPA from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 2.495V ±1.0% reference voltage, 0.1mA minimum cathode current for regulation, 120mA sink current capability, and 0.2Ω typical dynamic output impedance. It operates from 2.495V to 36V output range and serves as a high-stability voltage reference in feedback loops of isolated DC-DC converters.
For engineers reviewing the LA431NHPA datasheet, LA431NHPA pinout, LA431NHPA application, or LA431NHPA equivalent, this device is selected for its tight reference tolerance, low cathode current requirement, sharp turn-on characteristic, and TO92-3L package compatibility with legacy Zener-based designs requiring thermal stability across –40°C to +125°C.
Technical Context
The LA431NHPA functions as a programmable shunt reference where the cathode-anode voltage is set by external resistor dividers connected to the reference (R) and anode (A) terminals. Its internal bandgap reference and active output stage deliver stable regulation without external compensation under load transients.
It exhibits 20–35mV reference voltage deviation over –40°C to +125°C and maintains ≤0.5Ω dynamic impedance up to 1kHz, enabling effective error amplification in secondary-side feedback circuits of flyback and forward converters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495V ±1.0% at 1mA cathode current - defines accuracy of regulated output voltage setting |
| Output Voltage Range | 2.495V to 36V - set via external R1/R2 divider; enables flexible feedback scaling |
| Sink Current Capability | 120mA continuous - supports high-gain optocoupler drive and fast transient response |
| Dynamic Output Impedance | 0.2Ω typical at ≤1kHz - ensures minimal AC error injection into feedback path |
| Min Cathode Current | 0.1mA typical - allows stable regulation even with high-value feedback resistors |
| Thermal Stability | ±25mV max VREF drift over –40°C to +125°C - guarantees consistent loop gain across temperature |
| Absolute Max Cathode Voltage | 40V - sets safe operating margin above 36V max regulated output |
Pinout & Package
LA431NHPA uses the TO92-3L through-hole plastic package (UL 94V-0 rated), with 4.3–4.7mm body width, 12.7mm lead length, and 2.54mm lead pitch. Pin 1 = Reference (R), Pin 2 = Anode (A), Pin 3 = Cathode (C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| R (Pin 1) | Reference input | High-impedance node sensing divided output voltage; connects to top of R1–R2 divider |
| A (Pin 2) | Anode | Ground-referenced terminal; completes shunt current path when regulating |
| C (Pin 3) | Cathode | Output node sinking current into feedback network; connects to optocoupler LED anode or error amplifier |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable shunt regulation | Enables precise output voltage setting from 2.495V to 36V using only two external resistors |
| Sharp turn-on characteristic | Active output circuitry provides fast, clean regulation onset-replaces Zener diodes without soft knee behavior |
| Low cathode current requirement | 0.1mA typical minimum ensures stable operation with high-resistance feedback networks, reducing power loss |
| High thermal stability | Guaranteed ±1.0% reference tolerance and <35mV VREF drift over full industrial temperature range |
| Robust reliability | TO92-3L package rated UL 94V-0; MSL Level 1 (unlimited floor life); 150°C max junction temperature |
Applications
| Isolated Flyback SMPS | Programmable Bench Power Supply |
|---|---|
Use Scenario: Secondary-side voltage sensing in AC/DC adapters with optocoupler feedback. IC Role / Device Role / Timing Role: Shunt regulator providing precise reference to optocoupler LED, closing primary-side PWM control loop. Use Value: Enables ±1% output voltage accuracy over line/load/temperature with no secondary-side LDO required. |
Use Scenario: Adjustable voltage reference in lab-grade linear power supplies with digital DAC control. IC Role / Device Role / Timing Role: Programmable shunt element setting output voltage via microcontroller-driven resistor ladder. Use Value: Delivers 0.1% resolution and <0.5mV/°C drift, eliminating need for trimming potentiometers. |
| Industrial Sensor Signal Conditioning | LED Constant-Current Driver Reference |
Use Scenario: Stable excitation voltage source for bridge-based pressure/temperature sensors. IC Role / Device Role / Timing Role: Precision voltage reference feeding Wheatstone bridge and instrumentation amplifier. Use Value: Maintains sensor offset and gain stability across –40°C to +85°C ambient, improving measurement repeatability. |
Use Scenario: Reference node in analog dimming circuits for high-brightness LED arrays. IC Role / Device Role / Timing Role: Sets current-sense threshold for MOSFET gate driver in constant-current sink topology. Use Value: Ensures ±1.5% LED brightness consistency across 10:1 dimming range and 50°C ambient variation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDBVR | ±0.5% initial tolerance, SOT-23-3 package, 100mA max sink current | Requires PCB redesign for surface-mount layout; lower max current limits high-power optocoupler drive | Select when tighter initial accuracy and space-constrained layouts outweigh through-hole assembly needs |
| KA431AZTA | ±2.0% reference tolerance, TO92-3L package, 100mA sink current, higher 0.5mA min cathode current | Compatible pinout but looser tolerance and higher minimum cathode current reduce design margin in low-power feedback paths | Acceptable for cost-sensitive consumer power supplies where ±2% output regulation is sufficient |
Compared with TL431ACDBVR and KA431AZTA, LA431NHPA offers superior thermal stability (±1.0% vs ±2.0%) and lowest cathode current requirement (0.1mA vs 0.5mA), making it optimal for high-accuracy, low-quiescent-current isolated power supply designs using through-hole assembly.
Availability
LA431NHPA is available at Aetrix Electronics and suitable for isolated flyback SMPS, programmable bench power supplies, and industrial sensor signal conditioning requiring stable component supply, long-term manufacturability, and RoHS-compliant through-hole packaging.
Supply support for LA431NHPA 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 semiconductor company specializing in discrete, analog, and mixed-signal devices for power management, signal integrity, and protection applications.
The LA431 series belongs to Diodes' precision shunt regulator product line, engineered specifically for high-stability voltage reference and feedback control in isolated switching power supplies and industrial instrumentation.
FAQ
What is the maximum cathode-to-anode voltage LA431NHPA can withstand?
The absolute maximum cathode voltage (VKA) is 40V. Operation beyond this rating risks permanent damage. The device is specified for regulated output voltages up to 36V, providing a 4V safety margin. This limit applies regardless of cathode current level and must be respected in all transient and fault conditions.
Can LA431NHPA replace a standard Zener diode directly?
Yes - LA431NHPA is designed as a drop-in functional replacement for Zener diodes in shunt regulator applications. Its active circuitry delivers sharper turn-on, lower dynamic impedance (0.2Ω vs typical Zener's >10Ω), and tighter voltage tolerance (±1.0% vs ±5% for common Zeners), without requiring circuit rework beyond resistor value adjustment.
Does LA431NHPA require external capacitors for stability?
No external capacitor is required for basic regulation stability. The device remains stable with purely resistive feedback networks. However, a 1nF ceramic capacitor from cathode to anode is recommended in high-noise environments or when driving long PCB traces to suppress RF pickup and improve transient immunity.
How does the ±1.0% reference tolerance affect output voltage accuracy in a typical SMPS design?
In a standard optocoupler-feedback flyback converter, the ±1.0% VREF tolerance contributes directly to total output voltage error. Combined with resistor tolerance (e.g., ±1% R1/R2), temperature drift, and optocoupler CTR variation, it enables overall output regulation within ±2% over line, load, and temperature - meeting Class II commercial power supply specifications.
LA431NHPA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- 300 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92
LA431NHPA FAQ
1.How can I place an order for LA431NHPA through Aetrix?
Please submit a Request for Quotation (RFQ) for LA431NHPA 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 LA431NHPA reliable?
The price and inventory of LA431NHPA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LA431NHPA is usually 5 days.
3.What payment methods are accepted for LA431NHPA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LA431NHPA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LA431NHPA?
LA431NHPA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LA431NHPA 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 LA431NHPA?
For technical support, including LA431NHPA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LA431NHPA requirements.
6.How does Aetrix verify that LA431NHPA is sourced from the original manufacturer or authorized distributors?
All LA431NHPA 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 LA431NHPA meets industry standards.
7.What is the process for return or replacement of LA431NHPA?
All LA431NHPA units undergo pre-shipment inspection (PSI). If there is an issue with LA431NHPA, 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 LA431NHPA part is unused and in its original packaging.
Return procedure for LA431NHPA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LA431NHPA 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…
