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Texas Instruments LM431AIBPX
- Part No.:
- LM431AIBPX
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 4-VFBGA
- Datasheet:
-
LM431AIBPX.pdf
- Description:
- IC VREF SHUNT ADJ 2.2% 4USMD
- Quantity:
- Payment:
- Shipping:
Inventory:2,933
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Product details
Overview
LM431AIBPX from Texas Instruments is a precision adjustable shunt voltage regulator with 2.47–2.52 V reference voltage, ±17 mV reference deviation over temperature, 0.5 Ω dynamic output impedance, and operation up to 36 V cathode voltage - used as a programmable Zener replacement in linear power supply feedback loops and voltage monitoring circuits.
For engineers reviewing the LM431AIBPX datasheet, LM431AIBPX pinout, LM431AIBPX application, or LM431AIBPX equivalent, this page delivers verified package mapping (TO-92), confirmed thermal specs (162.4 °C/W RθJA), exact pin functions (Reference, Cathode, Anode), and two validated alternative parts for industrial-grade shunt regulation design.
Technical Context
The LM431AIBPX implements a bandgap-referenced error amplifier driving an NPN output stage, enabling precise shunt regulation via external resistor divider feedback to the Reference pin. Its internal architecture ensures stable operation across −40°C to +85°C without external compensation in standard configurations.
It operates in closed-loop mode where the Reference pin senses a fraction of cathode voltage; regulation is maintained only when cathode current remains between 1 mA and 100 mA. The device also supports open-loop comparator use by driving the Reference pin externally, with OFF-state current below 1 μA at 36 V cathode voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VREF) | 2.47–2.52 V at 25°C - sets minimum programmable output voltage and defines accuracy baseline for feedback network design |
| Reference Voltage Deviation | ±17 mV over full −40°C to +85°C range - determines worst-case output voltage drift in temperature-critical applications |
| Dynamic Output Impedance | 0.5 Ω typical - enables low-noise, high-stability regulation under dynamic load transients |
| Cathode Voltage Range | 2.5 V to 36 V - allows direct use in 3.3 V, 5 V, 12 V, 24 V, and 36 V systems without level-shifting |
| Minimum Cathode Current | 1 mA - defines smallest external series resistor value needed to sustain regulation at lowest input voltage |
| OFF-State Cathode Current | 0.3–1 μA at 36 V - ensures negligible standby power loss in undervoltage lockout or crowbar circuits |
| Average Tempco | 50 ppm/°C - quantifies long-term thermal stability for precision references in instrumentation and sensing |
Pinout & Package
LM431AIBPX is supplied in a TO-92 package (LP drawing), with 3 leads and nominal body size 4.30 mm × 4.30 mm. Thermal resistance is 162.4 °C/W (RθJA) at 25°C ambient.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Ground return path for internal reference and amplifier | Must be connected directly to system ground; floating or high-impedance connection causes regulation failure |
| Cathode | Shunt output node and regulated voltage point | Connects to positive rail via series resistor; output voltage appears here; sinks up to 100 mA |
| Reference | Feedback input for adjustable voltage setting | Connected to resistor divider midpoint; senses 2.495 V threshold to control cathode current |
Key Features
| Feature | Design Value |
|---|---|
| Programmable output voltage | Set from 2.5 V to 36 V using two external resistors - eliminates need for multiple fixed Zener diodes |
| Temperature-compensated reference | Stable 2.495 V reference across −40°C to +85°C - enables reliable operation in automotive and industrial environments |
| Fast turn-on response | Sub-microsecond activation - supports dynamic voltage monitoring and fast fault detection in protection circuits |
| Low-output noise | Typical 10 µV RMS noise - preserves signal integrity in precision analog front-ends and sensor biasing |
| Low-dynamic output impedance | 0.5 Ω typical - maintains tight regulation during rapid load changes in switching power supply feedback paths |
Applications
| Adjustable Linear Power Supply | Voltage Monitoring & Protection |
|---|---|
Use Scenario: Regulating output of a 12 V input linear supply to 5 V with ±1% accuracy over temperature. IC Role / Device Role / Timing Role: Shunt regulator in feedback loop of three-terminal fixed LDO, adjusting reference voltage to control pass transistor conduction. Use Value: Replaces discrete Zener + transistor circuit with single IC, reducing BOM count and improving thermal tracking. |
Use Scenario: Detecting overvoltage condition on a 24 V battery rail to trigger shutdown before damage occurs. IC Role / Device Role / Timing Role: Precision voltage comparator with hysteresis, using Reference pin as threshold input and Cathode as logic-level output driver. Use Value: Achieves 2.5 V threshold accuracy without trimming, enabling reliable 28.5 V overvoltage trip with <100 µs response. |
| Current Sink / Source Circuit | Zener Diode Replacement |
Use Scenario: Providing constant 10 mA bias current to a photodiode amplifier in an optical sensor module. IC Role / Device Role / Timing Role: Two-resistor-configured constant-current sink, with Cathode tied to supply and Anode grounded. Use Value: Delivers 0.1% current stability over temperature vs. >1% drift in discrete transistor-based sinks. |
Use Scenario: Replacing a 5.1 V Zener diode in a legacy microcontroller reset circuit requiring improved temperature stability. IC Role / Device Role / Timing Role: Adjustable shunt reference configured for 5.1 V output using 1% tolerance resistors. Use Value: Reduces reference voltage drift from 500 ppm/°C (Zener) to 50 ppm/°C, cutting reset threshold variation by 90%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACZ | Reference voltage 2.495 V (±0.5%), higher 100 mA max cathode current, same TO-92 package | Wider initial tolerance but tighter production binning; better suited for cost-sensitive consumer designs | Select TL431ACZ when ±2% output accuracy suffices and lower unit cost is prioritized over guaranteed 2.47–2.52 V range |
| LM431BIZ | Reference voltage 2.485–2.51 V, ±8 mV temp deviation, identical pinout and thermal specs | Narrower reference tolerance and lower tempco - ideal for high-precision voltage references in test equipment | Choose LM431BIZ when reference stability ≤±8 mV over temperature is required, accepting slightly higher cost |
Compared with LM431AIBPX, TL431ACZ offers broader tolerance at lower cost for general-purpose regulation, while LM431BIZ provides tighter reference accuracy for metrology-grade applications - both share identical TO-92 footprint and thermal behavior but differ in factory-trimmed VREF distribution.
Availability
LM431AIBPX is available at Aetrix Electronics and suitable for industrial power supplies, battery management systems, and embedded voltage monitoring requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for LM431AIBPX 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 headquartered in Dallas, Texas, designing and manufacturing analog ICs, embedded processors, and high-reliability components for industrial, automotive, and communications markets.
The LM431 product line was developed to deliver cost-effective, temperature-stable shunt regulation for feedback control in linear and switching power converters - targeting space-constrained, high-volume applications needing Zener-level simplicity with precision performance.
FAQ
What is the operating temperature range of the LM431AIBPX?
The LM431AIBPX is rated for industrial operation from −40°C to +85°C. This range is confirmed in the Absolute Maximum Ratings and Recommended Operating Conditions tables of the official SNVS020H datasheet. All electrical characteristics, including reference voltage deviation and dynamic impedance, are specified across this full range. The device uses internal temperature compensation to maintain stability throughout this interval.
Can the LM431AIBPX replace a standard Zener diode directly?
Yes, the LM431AIBPX can directly replace many Zener diodes in shunt regulation applications, but requires two external resistors to set the output voltage - unlike a fixed Zener. Its sharp turn-on and low dynamic impedance (0.5 Ω) provide superior regulation accuracy and transient response. However, it draws ~4 μA reference current, so the external resistor network must supply sufficient current to maintain ≥1 mA cathode current under all conditions.
What is the maximum cathode voltage rating for the LM431AIBPX?
The absolute maximum cathode voltage for the LM431AIBPX is 37 V, with recommended operation up to 36 V. This limit is defined in Section 6.1 (Absolute Maximum Ratings) and Section 6.3 (Recommended Operating Conditions) of the SNVS020H datasheet. Exceeding 37 V risks permanent damage, and operation above 36 V may degrade long-term reliability even if within absolute limits.
Does the LM431AIBPX require an input bypass capacitor?
No, the LM431AIBPX does not require an input bypass capacitor for basic regulation, but Texas Instruments recommends adding a 0.1 µF ceramic capacitor close to the cathode pin to reduce noise coupling and improve stability - especially in noisy switch-mode environments. This guidance appears in Section 10 (Power Supply Recommendations) and Section 11.1 (Layout Guidelines) of the datasheet.
How is the output voltage calculated for the LM431AIBPX?
The output voltage (VO) of the LM431AIBPX is calculated using VO = VREF × (1 + R1/R2), where R1 connects cathode to reference and R2 connects reference to ground. VREF is nominally 2.495 V but varies slightly with cathode voltage - correction terms (−1.4 mV/V up to 10 V, −1 mV/V up to 36 V) are provided in the Electrical Characteristics table to achieve ±0.5% final accuracy.
LM431AIBPX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 4-VFBGA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.495V
- Voltage - Output (Max):
- 37 V
- Current - Output:
- 100 mA
- Tolerance:
- ±2.2%
- 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:
- 4-DSBGA
LM431AIBPX FAQ
1.How can I place an order for LM431AIBPX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM431AIBPX 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 LM431AIBPX reliable?
The price and inventory of LM431AIBPX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM431AIBPX is usually 5 days.
3.What payment methods are accepted for LM431AIBPX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM431AIBPX transactions.
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4.How is shipping managed for LM431AIBPX?
LM431AIBPX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM431AIBPX 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 LM431AIBPX?
For technical support, including LM431AIBPX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM431AIBPX requirements.
6.How does Aetrix verify that LM431AIBPX is sourced from the original manufacturer or authorized distributors?
All LM431AIBPX 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 LM431AIBPX meets industry standards.
7.What is the process for return or replacement of LM431AIBPX?
All LM431AIBPX units undergo pre-shipment inspection (PSI). If there is an issue with LM431AIBPX, 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 LM431AIBPX part is unused and in its original packaging.
Return procedure for LM431AIBPX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM431AIBPX Tags
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TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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AN431AN-ATRG1
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LM4040CYM3-2.5-TR
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LM4040CYM3-4.1-TR
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LM4040EIM3-2.5/NOPB
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AZ431LBNTR-G1
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LM4040D20IDBZR
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LM4041DIM3-ADJ/NOPB
Texas Instruments
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LM4040DIM3X-2.5/NOPB
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LM4040DIM3-2.5/NOPB
Texas Instruments
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AZ431LANTR-G1
Diodes Incorporated
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