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Texas Instruments LM431BIM/NOPB
- Part No.:
- LM431BIM/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM431BIM/NOPB.pdf
- Description:
- IC VREF SHUNT ADJ 1% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:463
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Product details
Overview
LM431BIM/NOPB from Texas Instruments is a precision adjustable shunt voltage regulator in SOIC-8 package, featuring 2.50 V nominal reference voltage (±10 mV tolerance), 50 ppm/°C average temperature coefficient, 0.5 Ω typical dynamic output impedance, and guaranteed operation from –40°C to +85°C. It replaces Zener diodes in feedback loops of linear and switching power supplies requiring stable 2.5–36 V programmable output.
For engineers reviewing the LM431BIM/NOPB datasheet, LM431BIM/NOPB pinout, LM431BIM/NOPB application, or LM431BIM/NOPB equivalent, this page delivers verified electrical specs, SOIC-8 terminal mapping, thermal derating guidance, and validated alternatives for industrial-grade shunt regulation designs.
Technical Context
The LM431BIM/NOPB operates as a 3-terminal programmable shunt regulator with internal bandgap reference and error amplifier. Its cathode regulates voltage by sinking variable current based on reference pin voltage feedback via external resistor divider.
It functions in closed-loop mode (reference tied to output via R1/R2) with 1–100 mA cathode current range, or open-loop comparator mode. Stability requires careful selection of series resistor (RS) and optional bypass capacitors per layout guidelines.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference voltage (VREF) | 2.50 V ±10 mV at 10 mA - sets minimum programmable output; defines accuracy baseline for 2.5–36 V adjustment range |
| Temperature coefficient | 50 ppm/°C average - ensures ≤1.75 mV drift over –40°C to +85°C, critical for precision references |
| Dynamic output impedance | 0.5 Ω typical at DC - enables low-noise, high-PSRR regulation without external compensation |
| Cathode current range | 1 mA to 100 mA - determines minimum load current handling and maximum shunt capability |
| Operating temperature | –40°C to +85°C - qualified for industrial environments; SOIC-8 package supports 0.81 W max power dissipation at 25°C |
| ESD rating (HBM) | ±2500 V - requires standard ESD handling but no special protection circuitry in board design |
Pinout & Package
LM431BIM/NOPB uses an 8-pin SOIC (D) package (4.90 mm × 3.91 mm body), with pins 2 and 8 assigned to Reference and Cathode respectively; pins 3, 6, and 7 are Anode (internally connected); pins 4 and 5 are NC (not internally connected).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Cathode | Main output terminal; connects to regulated voltage node and series current-limiting resistor |
| Pin 2 | Reference | Sense input for feedback divider; must be driven to 2.50 V to maintain regulation |
| Pins 3, 6, 7 | Anode | Ground return path; all three pins are internally shorted and must be connected to system ground |
| Pins 4, 5 | NC | No internal connection; left unconnected on PCB; no routing or copper required |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage | Programmable from 2.5 V to 36 V using two external resistors - eliminates need for multiple fixed-voltage Zeners |
| Low-output noise | Sub-mV RMS noise floor - suitable for sensitive analog circuits and precision ADC references |
| Fast turn-on response | Microsecond-scale activation - supports dynamic load transient recovery in SMPS feedback paths |
| Temperature-compensated reference | Stable over full –40°C to +85°C range - removes need for external thermal compensation networks |
Applications
| Switch-Mode Power Supply Feedback | Voltage Monitoring Circuit |
|---|---|
Use Scenario: Used in optocoupler-coupled secondary-side feedback loop of isolated DC-DC converters. IC Role / Device Role / Timing Role: Shunt regulator providing precise 2.5 V reference to drive optocoupler LED; sets output voltage via R1/R2 divider. Use Value: Enables ±1% output regulation across line/load/temperature; replaces discrete Zener + transistor solution with single IC. |
Use Scenario: Detects overvoltage condition on a 12 V rail to trigger shutdown logic. IC Role / Device Role / Timing Role: Precision threshold detector; reference pin biased to 12 V via resistor divider; cathode drives comparator input. Use Value: Achieves 12.0 V trip point with <±50 mV error over temperature - superior to standard Zener-based monitors. |
| Current Sink / Source | Zener Diode Replacement |
Use Scenario: Provides constant 10 mA sink for LED biasing in industrial sensor interface. IC Role / Device Role / Timing Role: Adjustable shunt regulator configured as two-terminal current source with cathode as output. Use Value: Delivers stable 10 mA with <0.5% variation from 5 V to 24 V supply - eliminates trim pot and improves long-term stability. |
Use Scenario: Replaces 3.3 V Zener diode in microcontroller reset circuit. IC Role / Device Role / Timing Role: Programmable shunt reference set to 3.3 V; anode grounded, cathode tied to reset pin via pull-up. Use Value: Reduces voltage tolerance from ±5% (Zener) to ±0.4%, improving reset accuracy and system reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBVR | 2.5 V reference, ±2% initial tolerance (vs. LM431BIM/NOPB's ±0.4%), 92 ppm/°C tempco, SOT-23-3 package | Limited to commercial temp range (0°C to 70°C); lower accuracy makes it unsuitable for industrial monitoring | Select when cost sensitivity outweighs precision and temperature range requirements |
| AS431ASTR-E1 | 2.5 V reference, ±1% tolerance, 100 ppm/°C tempco, SOIC-8 package, -40°C to +85°C rating | Higher dynamic impedance (1.2 Ω vs. 0.5 Ω) reduces PSRR; not recommended for low-noise reference applications | Choose for drop-in replacement where absolute precision is secondary to supply chain diversification |
Compared with TL431CDBVR and AS431ASTR-E1, LM431BIM/NOPB delivers tighter reference tolerance (±0.4%), lower tempco (50 ppm/°C), and lower dynamic impedance (0.5 Ω), making it optimal for industrial power supply feedback and precision voltage monitoring where stability over temperature is critical.
Availability
LM431BIM/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, voltage monitoring systems, and precision current sink circuits requiring stable component supply across extended temperature ranges.
Supply support for LM431BIM/NOPB 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
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision voltage references and power management ICs.
The LM431 product line was designed for high-accuracy shunt regulation in industrial, telecom, and computing power systems-emphasizing temperature stability, low dynamic impedance, and flexible programmability.
FAQ
What is the reference voltage tolerance of LM431BIM/NOPB?
The LM431BIM/NOPB has a reference voltage (VREF) of 2.50 V with a tolerance of ±10 mV (±0.4%) at 10 mA and 25°C. This tight tolerance is specified for the 'B' grade and remains stable across its –40°C to +85°C operating range, enabling high-accuracy programmable outputs in LM431BIM/NOPB-based designs.
Can LM431BIM/NOPB replace a standard Zener diode directly?
Yes, LM431BIM/NOPB can directly replace many Zener diodes in shunt regulator configurations, but requires two external resistors to set the output voltage. Unlike a passive Zener, LM431BIM/NOPB needs ≥1 mA cathode current to regulate and offers superior temperature stability, lower dynamic impedance, and adjustable voltage - making LM431BIM/NOPB ideal for precision upgrades.
What is the maximum cathode voltage for LM431BIM/NOPB?
The absolute maximum cathode voltage for LM431BIM/NOPB is 37 V, as specified in the Absolute Maximum Ratings table. For reliable operation, the recommended maximum cathode voltage is 36 V under normal conditions. Exceeding 37 V risks permanent damage to the LM431BIM/NOPB device.
How does the SOIC-8 package of LM431BIM/NOPB affect thermal performance?
The SOIC-8 package of LM431BIM/NOPB has a junction-to-ambient thermal resistance (RθJA) of 126.9°C/W. At 25°C ambient, its maximum power dissipation is 0.81 W; above that temperature, it must be derated at 6.5 mW/°C. Proper PCB copper area and airflow are essential to maintain safe junction temperatures in LM431BIM/NOPB applications.
Is LM431BIM/NOPB RoHS compliant and lead-free?
Yes, LM431BIM/NOPB is RoHS compliant and features lead-free (Sn) termination, as confirmed in TI's official packaging addendum. The "NOPB" suffix explicitly denotes lead-free, green-compliant packaging. All LM431BIM/NOPB units supplied by Aetrix Electronics meet current EU RoHS Directive requirements and JEDEC J-STD-020 moisture sensitivity Level-1 standards.
LM431BIM/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.495V
- Voltage - Output (Max):
- 37 V
- Current - Output:
- 100 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- 50ppm/°C Typical
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM431BIM/NOPB FAQ
1.How can I place an order for LM431BIM/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM431BIM/NOPB 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 LM431BIM/NOPB reliable?
The price and inventory of LM431BIM/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM431BIM/NOPB is usually 5 days.
3.What payment methods are accepted for LM431BIM/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM431BIM/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM431BIM/NOPB?
LM431BIM/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM431BIM/NOPB 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 LM431BIM/NOPB?
For technical support, including LM431BIM/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM431BIM/NOPB requirements.
6.How does Aetrix verify that LM431BIM/NOPB is sourced from the original manufacturer or authorized distributors?
All LM431BIM/NOPB 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 LM431BIM/NOPB meets industry standards.
7.What is the process for return or replacement of LM431BIM/NOPB?
All LM431BIM/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM431BIM/NOPB, 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 LM431BIM/NOPB part is unused and in its original packaging.
Return procedure for LM431BIM/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM431BIM/NOPB Tags
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