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Texas Instruments LM431BIMX/NOPB
- Part No.:
- LM431BIMX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM431BIMX/NOPB.pdf
- Description:
- IC VREF SHUNT ADJ 1% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,256
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Product details
Overview
LM431BIMX/NOPB from Texas Instruments is a precision adjustable shunt regulator IC with 2.5 V reference voltage, ±10 mV initial tolerance (B-grade), 50 ppm/°C average temperature coefficient, and 0.5 Ω dynamic output impedance - used as a programmable Zener replacement in feedback loops of linear and switching power supplies.
For engineers reviewing the LM431BIMX/NOPB datasheet, LM431BIMX/NOPB pinout, LM431BIMX/NOPB application, or LM431BIMX/NOPB equivalent, this page delivers verified electrical specs, SOIC-8 package mapping, thermal derating guidance, and real-world use cases for voltage monitoring, current sinking, and overvoltage protection circuits.
Technical Context
The LM431BIMX/NOPB operates as a 3-terminal shunt regulator where cathode voltage is set by an external resistor divider connected to the reference pin; regulation is achieved by dynamically shunting current from cathode to anode based on reference input error. It functions across –40°C to +85°C with guaranteed stability under 1 mA to 100 mA cathode current.
Its internal bandgap reference and error amplifier enable precise output voltage programming from 2.5 V to 36 V. The device exhibits low-output noise and fast turn-on response, making it suitable for closed-loop feedback control and open-loop comparator applications when driven externally.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference voltage (VREF) | 2.50 V (typ), ±10 mV (max deviation at 25°C) - defines minimum programmable output and sets accuracy baseline for feedback networks. |
| Temperature coefficient | 50 ppm/°C (average) - ensures ≤0.35% output drift over –40°C to +85°C industrial range. |
| Dynamic output impedance | 0.5 Ω (typ at DC) - maintains tight regulation under load transients without external compensation. |
| Cathode current range | 1 mA to 100 mA - determines minimum bias and maximum shunt capability; below 1 mA, regulation ceases. |
| Reference input current | 2–4 μA (typ) - enables high-impedance feedback dividers with minimal loading error. |
| Max cathode voltage | 36 V - supports wide-input power supply designs up to 36 V without external clamping. |
| ESD rating (HBM) | ±2500 V - meets standard handling requirements for automated assembly without special ESD controls. |
Pinout & Package
LM431BIMX/NOPB is housed in an 8-pin SOIC (D) package (4.90 mm × 3.91 mm body), rated for industrial temperature range (–40°C to +85°C). Pins 4 and 5 are internally unconnected (NC); pin 1 is cathode (I/O), pins 2 and 3 are anode (O), pin 8 is reference (I).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Cathode | Main output node; connects to supply rail and feedback network; sinks regulated current. |
| Pins 2, 3 | Anode | Ground return path; must be low-impedance connection to system ground for stable regulation. |
| Pins 4, 5 | NC | No internal connection; left floating or tied to ground per layout best practice (no functional impact). |
| Pin 8 | Reference | Sense input for feedback divider; high-impedance node requiring clean routing away from noise sources. |
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 dynamic output impedance | 0.5 Ω typical - minimizes output voltage variation during load steps without added capacitance. |
| Fast turn-on response | Sub-microsecond activation - supports dynamic feedback correction in high-frequency SMPS designs. |
| Low-output noise | Typical <10 µVRMS - preserves signal integrity in precision analog monitoring and sensing paths. |
| Temperature-compensated reference | Stable over full –40°C to +85°C range - enables reliable operation in automotive and industrial environments. |
Applications
| Switch-Mode Power Supply Feedback | Voltage Monitoring Circuit |
|---|---|
|
Use Scenario: Used in secondary-side feedback loop of isolated flyback converters to regulate output voltage via optocoupler-coupled signal. IC Role / Device Role / Timing Role: Precision shunt regulator providing stable 2.5 V reference for error amplifier comparison against scaled output voltage. Use Value: Enables ±1% output regulation across line/load/temperature with minimal external components and no trimming required. |
Use Scenario: Detects overvoltage condition on a 12 V rail and triggers shutdown logic when voltage exceeds 12.6 V. IC Role / Device Role / Timing Role: Adjustable threshold comparator - reference pin biased by resistor divider; cathode pulled high upon trip. Use Value: Provides accurate, temperature-stable trip point without calibration; replaces discrete op-amp + Zener solution. |
| Constant Current Sink | Crowbar Overvoltage Protection |
|
Use Scenario: Sinks fixed 20 mA from LED string in constant-current driver for optical isolation interface. IC Role / Device Role / Timing Role: Shunt regulator configured with fixed cathode-to-anode voltage drop and series sense resistor. Use Value: Delivers stable current independent of supply variation (15–24 V) and junction temperature drift. |
Use Scenario: Triggers SCR gate when 5 V supply exceeds 5.5 V, shorting rail to ground and blowing fuse. IC Role / Device Role / Timing Role: Precision voltage threshold detector driving SCR gate through current-limiting resistor. Use Value: Responds within microseconds to overvoltage events; avoids damage to downstream 5 V logic circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBVR | Same 2.5 V reference, but C-grade (±2% initial tolerance vs. B-grade ±0.5%), higher 100 ppm/°C tempco, SOT-23-3 package. | Limited to lower-power, space-constrained designs; unsuitable for high-accuracy industrial monitoring. | Select TL431CDBVR only when cost and footprint outweigh precision and thermal stability requirements. |
| AS431ASTZTR-G1 | Pin-compatible SOIC-8, same 2.5 V reference, but A-grade (±1% tolerance), 100 ppm/°C tempco, 1.5 mA min cathode current. | Requires higher minimum bias current; less stable over temperature than LM431BIMX/NOPB in extended-range applications. | Choose AS431ASTZTR-G1 only if dual-sourcing is mandated and ±1% output accuracy is acceptable. |
Compared with TL431CDBVR and AS431ASTZTR-G1, the LM431BIMX/NOPB offers superior thermal stability (50 ppm/°C), tighter initial tolerance (±10 mV), and lower dynamic impedance (0.5 Ω), making it preferred for industrial power supplies and precision voltage references where long-term accuracy matters.
Availability
LM431BIMX/NOPB is available at Aetrix Electronics and suitable for switch-mode power supplies, voltage monitoring systems, and crowbar protection circuits requiring stable component supply across industrial temperature ranges and multi-year production cycles.
Supply support for LM431BIMX/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 company specializing in analog and embedded processing technologies, with leadership in precision analog ICs and power management solutions.
The LM431 product line was designed for high-accuracy, temperature-stable shunt regulation in power supply feedback, voltage supervision, and current-source applications - targeting industrial, telecom, and computing infrastructure.
FAQ
What is the operating temperature range of the LM431BIMX/NOPB?
The LM431BIMX/NOPB is rated for industrial operation from –40°C to +85°C. This range is confirmed in the TI datasheet's Recommended Operating Conditions table and applies specifically to the "I" grade suffix in the part number. Derating of power dissipation begins above 25°C ambient, with SOIC package thermal resistance specified at 126.9°C/W.
How does the LM431BIMX/NOPB differ from the LM431ACM/NOPB?
The LM431BIMX/NOPB features B-grade reference tolerance (±10 mV) and industrial temperature range (–40°C to +85°C), while LM431ACM/NOPB is A-grade (±8 mV) but commercial range (0°C to +70°C). Both share identical SOIC-8 packaging and electrical architecture, but LM431BIMX/NOPB is selected for harsher thermal environments where long-term stability matters.
Can the LM431BIMX/NOPB replace a standard Zener diode directly?
Yes - the LM431BIMX/NOPB functions as a 2.5 V precision Zener with programmable output up to 36 V. Unlike passive Zeners, it requires only two external resistors for adjustment and delivers far better temperature stability (50 ppm/°C vs. 100–500 ppm/°C), lower dynamic impedance (0.5 Ω vs. 5–50 Ω), and tighter initial tolerance.
What is the minimum cathode current required for regulation in the LM431BIMX/NOPB?
The LM431BIMX/NOPB requires a minimum cathode current of 1 mA to maintain regulation, as specified in the Recommended Operating Conditions table. Below this value, the device exits regulation and output voltage collapses. This parameter is critical when sizing the series resistor in shunt regulator designs.
Is the LM431BIMX/NOPB RoHS compliant and lead-free?
Yes - the LM431BIMX/NOPB is RoHS compliant and features 100% matte tin (Sn) lead finish, as documented in TI's Package Option Addendum. It carries the "NOPB" suffix indicating lead-free packaging and meets JEDEC Level-1 moisture sensitivity standards with unlimited floor life at ≤30°C/60% RH.
LM431BIMX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- 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):
- 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
LM431BIMX/NOPB FAQ
1.How can I place an order for LM431BIMX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM431BIMX/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 LM431BIMX/NOPB reliable?
The price and inventory of LM431BIMX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM431BIMX/NOPB is usually 5 days.
3.What payment methods are accepted for LM431BIMX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM431BIMX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM431BIMX/NOPB?
LM431BIMX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM431BIMX/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 LM431BIMX/NOPB?
For technical support, including LM431BIMX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM431BIMX/NOPB requirements.
6.How does Aetrix verify that LM431BIMX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM431BIMX/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 LM431BIMX/NOPB meets industry standards.
7.What is the process for return or replacement of LM431BIMX/NOPB?
All LM431BIMX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM431BIMX/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 LM431BIMX/NOPB part is unused and in its original packaging.
Return procedure for LM431BIMX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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