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Diodes Incorporated LA431OHPA
- Part No.:
- LA431OHPA
- Manufacturer:
- Diodes Incorporated
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
LA431OHPA.pdf
- Description:
- IC VREF SHUNT ADJ TO92
- Quantity:
- Payment:
- Shipping:
Inventory:3,116
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Product details
Overview
LA431OHPA from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 2.495 V ±0.4% reference voltage, 0.2 Ω typical dynamic output impedance, and 120 mA sink current capability in TO-92-3L package. It replaces Zener diodes in feedback loops of switching mode power supplies and voltage reference circuits requiring tight regulation over -40°C to +125°C.
For engineers reviewing the LA431OHPA datasheet, LA431OHPA pinout, LA431OHPA application, or LA431OHPA equivalent, this page delivers verified electrical specs, thermal performance data, TO-92-3L terminal mapping, and real-world use cases for stable voltage reference design.
Technical Context
The LA431OHPA operates as a programmable shunt regulator where cathode-to-anode voltage (VKA) is set via external resistive divider connected to the reference (R) pin. Its active output stage enables sharp turn-on behavior below 0.1 mA minimum cathode current, distinguishing it from passive Zener diodes.
It maintains ±0.4% initial reference tolerance and ≤35 mV deviation over full -40°C to +125°C operating range, with low 0.2 Ω dynamic impedance ensuring stable regulation under transient load conditions up to 120 mA sink current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V ±0.4% - sets precise regulation threshold for feedback networks |
| Sink Current Capability | 120 mA - supports high-current error amplifier drive in SMPS feedback paths |
| Dynamic Output Impedance | 0.2 Ω (typ.) - minimizes output voltage variation during fast load transients |
| Min Cathode Current | 0.1 mA (typ.) - enables stable regulation at ultra-low bias currents |
| Output Voltage Range | 2.495 V to 36 V - adjustable via two external resistors per application circuit |
| Operating Temperature | -40°C to +125°C - qualified for industrial and automotive under-hood environments |
| Cathode Voltage Max | 40 V - defines absolute maximum stress limit for safe operation |
Pinout & Package
LA431OHPA uses the TO-92-3L through-hole plastic package (UL 94V-0 rated), with 4.3–4.7 mm body width, 12.7 mm lead length, and 2.54 mm lead pitch. Pin 1 = Reference (R), Pin 2 = Anode (A), Pin 3 = Cathode (C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (R) | Reference Input | High-impedance node sensing internal 2.495 V bandgap; connects to resistor divider midpoint |
| Pin 2 (A) | Anode | Ground or low-side return path; establishes cathode-to-anode potential difference |
| Pin 3 (C) | Cathode | Current-sinking output node; regulates voltage by shunting excess current to anode |
Key Features
| Feature | Design Value |
|---|---|
| Thermal stability | ≤35 mV VREF deviation across -40°C to +125°C - ensures consistent regulation without recalibration |
| Sharp turn-on characteristic | Active output circuitry enables <0.1 mA regulation onset - improves light-load efficiency vs. Zener diodes |
| Low dynamic impedance | 0.2 Ω typical - suppresses ripple and noise in feedback loops of isolated DC-DC converters |
| RoHS & Halogen Free | Compliant TO-92-3L taping - meets IPC-JEDEC J-STD-020D.1 MSL Level 1 moisture sensitivity requirements |
Applications
| Switching Mode Power Supply | Voltage Reference Circuit |
|---|---|
Use Scenario: Secondary-side feedback in isolated flyback or forward converters regulating 5 V, 12 V, or 24 V outputs. IC Role / Device Role / Timing Role: Shunt regulator providing precise voltage reference to optocoupler input, enabling primary-side PWM controller adjustment. Use Value: ±0.4% reference tolerance and 0.2 Ω impedance maintain <±1% output regulation across line/load/temperature variations. | Use Scenario: Precision 2.5 V reference for ADCs, DACs, or comparator thresholds in data acquisition systems. IC Role / Device Role / Timing Role: Adjustable shunt reference generating stable voltage independent of supply rail fluctuations. Use Value: 0.1 mA min cathode current allows operation from high-impedance dividers, reducing power consumption in battery-powered sensors. |
| Programmable Overvoltage Protection | Linear Regulator Error Amplifier |
Use Scenario: Threshold detection in DC bus monitoring for industrial motor drives or solar inverters. IC Role / Device Role / Timing Role: Adjustable shunt element triggering protection logic when bus voltage exceeds user-defined limit (e.g., 30 V). Use Value: 2.495–36 V programmability enables single BOM part for multiple overvoltage trip points without redesign. | Use Scenario: Error amplifier reference in low-dropout linear regulators powering FPGA I/O banks. IC Role / Device Role / Timing Role: Stable reference source for LDO feedback loop controlling pass transistor gate voltage. Use Value: Low 0.2 Ω output impedance prevents reference droop during fast load transients, improving transient response. |
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 | 2.5 V ±0.5%, SOT-23-3 package, 100 mA sink, 0.22 Ω impedance | Surface-mount only; lower max sink current limits high-power SMPS feedback use | Select for space-constrained PCBs where TO-92 footprint is unavailable |
| KA431AZTA | 2.5 V ±2.0%, TO-92-3L, 100 mA sink, 0.3 Ω impedance | Looser tolerance and higher impedance reduce regulation accuracy in precision feedback | Acceptable for cost-sensitive consumer power adapters where ±2% output tolerance is acceptable |
Compared with TL431ACDBVR and KA431AZTA, LA431OHPA offers tighter ±0.4% reference tolerance and higher 120 mA sink capacity-critical for maintaining regulation stability in high-current, wide-temperature industrial power supplies.
Availability
LA431OHPA is available at Aetrix Electronics and suitable for switching mode power supplies, voltage reference circuits, and programmable overvoltage protection systems requiring stable component supply with guaranteed long-term availability.
Supply support for LA431OHPA 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 and manufacturing operations across Asia and the Americas.
The LA431 belongs to Diodes' precision shunt regulator product line, engineered specifically for high-accuracy voltage reference and feedback control in industrial, computing, and communications power systems.
FAQ
What is the minimum cathode current required for regulation in LA431OHPA?
The LA431OHPA requires a typical minimum cathode current of 0.1 mA to maintain regulation, with a maximum specified value of 0.3 mA across temperature. This low threshold enables stable operation with high-value resistor dividers, reducing quiescent power in battery-powered applications.
Can LA431OHPA replace a standard Zener diode directly in existing designs?
Yes-LA431OHPA can directly replace Zener diodes in shunt regulator configurations, provided the anode is grounded and the reference pin connects to the resistor divider midpoint. Its active turn-on and tighter tolerance improve regulation accuracy without changing external component values.
What is the thermal resistance (junction-to-ambient) for LA431OHPA in TO-92-3L package?
The LA431OHPA in TO-92-3L has a junction-to-ambient thermal resistance (θJA) of 150 °C/W. At 120 mA sink current and 36 V cathode voltage, power dissipation reaches 4.32 W-exceeding its 625 mW rating-so practical designs must limit VKA × IKA to stay within safe operating area.
Is LA431OHPA suitable for automotive applications?
LA431OHPA is qualified for operation from -40°C to +125°C and meets RoHS/Halogen-Free requirements, making it suitable for under-hood automotive auxiliary power modules. However, it is not AEC-Q101 qualified; for safety-critical automotive systems, Diodes' AEC-Q101-certified shunt regulators should be used instead.
LA431OHPA 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:
- ±0.4%
- 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
LA431OHPA FAQ
1.How can I place an order for LA431OHPA through Aetrix?
Please submit a Request for Quotation (RFQ) for LA431OHPA 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 LA431OHPA reliable?
The price and inventory of LA431OHPA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LA431OHPA is usually 5 days.
3.What payment methods are accepted for LA431OHPA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LA431OHPA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LA431OHPA?
LA431OHPA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LA431OHPA 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 LA431OHPA?
For technical support, including LA431OHPA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LA431OHPA requirements.
6.How does Aetrix verify that LA431OHPA is sourced from the original manufacturer or authorized distributors?
All LA431OHPA 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 LA431OHPA meets industry standards.
7.What is the process for return or replacement of LA431OHPA?
All LA431OHPA units undergo pre-shipment inspection (PSI). If there is an issue with LA431OHPA, 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 LA431OHPA part is unused and in its original packaging.
Return procedure for LA431OHPA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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