LM431BCM Equivalent & Substitute Parts

Part Overview

The LM431BCM is a shunt voltage reference IC manufactured by onsemi, classified as a Power Management (PMIC) component. This adjustable reference device operates across a 2.495V to 36V output range with ±1% tolerance and 100 mA output capability in an 8-SOIC surface mount package. The LM431BCM is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. Substitute parts maintain the same electrical specifications and package footprint while offering active product status and improved availability.

Key Parameters

Parameter	Value
Reference Type	Shunt
Output Type	Adjustable
Voltage - Output (Min/Fixed)	2.495V
Voltage - Output (Max)	36V
Current - Output	100 mA
Tolerance	±1%
Temperature Coefficient	50ppm/°C Typical
Current - Cathode	1 mA
Operating Temperature	-25°C ~ 85°C (TA)
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the LM431BCM is determined by the following critical parameters: reference type (shunt), output type (adjustable), voltage output range (2.495V to 36V), current output (100 mA), package type (8-SOIC), and mounting method (surface mount). Parts are grouped into three categories based on tolerance specification and product status:

Direct Equivalent (±1% Tolerance): LM431BCMX maintains identical electrical specifications and tolerance, differing only in manufacturer designation and product status (active vs. obsolete).

Similar Substitutes (±0.4% to ±2.2% Tolerance): TL431 series variants offer tighter or comparable tolerance specifications with active product status. These parts are electrically compatible within the same package footprint. Tolerance variations (±0.4%, ±2.2%) represent performance enhancements or cost-optimized alternatives.

Upgrade Option (±1% Tolerance, Extended Temperature): TL431AIDT from STMicroelectronics provides equivalent tolerance with extended operating temperature range (-40°C to 105°C) and reduced cathode current (700 µA vs. 1 mA), suitable for applications requiring broader thermal performance.

Parameter Comparison

Part Number	Manufacturer	Tolerance	Output Voltage Range	Current - Output	Current - Cathode	Operating Temperature	Product Status	Packaging
LM431BCM	onsemi	±1%	2.495V - 36V	100 mA	1 mA	-25°C ~ 85°C	Obsolete	8-SOIC
LM431BCMX	National Semiconductor	±1%	2.495V - 36V	100 mA	1 mA	-25°C ~ 85°C	Active	8-SOIC
TL431ACDG	onsemi	±1%	2.495V - 36V	100 mA	1 mA	0°C ~ 70°C	Active	8-SOIC (Tube)
TL431ACDR2G	onsemi	±1%	2.495V - 36V	100 mA	1 mA	0°C ~ 70°C	Active	8-SOIC (TR)
TL431BCDR2G	onsemi	±0.4%	2.495V - 36V	100 mA	1 mA	0°C ~ 70°C	Active	8-SOIC (TR)
TL431BIDG	onsemi	±0.4%	2.495V - 36V	100 mA	1 mA	-40°C ~ 85°C	Active	8-SOIC (Tube)
TL431BIDR2G	onsemi	±0.4%	2.495V - 36V	100 mA	1 mA	-40°C ~ 85°C	Active	8-SOIC (TR)
TL431BVDR2G	onsemi	±0.4%	2.495V - 36V	100 mA	1 mA	-40°C ~ 125°C	Active	8-SOIC (TR)
TL431CDR2G	onsemi	±2.2%	2.495V - 36V	100 mA	1 mA	0°C ~ 70°C	Active	8-SOIC (TR)
TL431IDR2G	onsemi	±2.2%	2.495V - 36V	100 mA	1 mA	-40°C ~ 85°C	Active	8-SOIC (TR)
TL431AIDT	STMicroelectronics	±1%	2.495V - 36V	100 mA	700 µA	-40°C ~ 105°C	Active	8-SOIC (CT & Digi-Reel)

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications): LM431BCMX is the primary equivalent, maintaining ±1% tolerance and identical operating temperature range. This part is recommended when design specifications require exact parameter matching and active product status is required.

For Cost-Optimized Designs: TL431CDR2G and TL431IDR2G offer ±2.2% tolerance with active status. These parts are suitable for applications where tolerance relaxation is acceptable and cost reduction is prioritized. TL431IDR2G extends the lower temperature limit to -40°C for enhanced cold-weather performance.

For Precision Applications: TL431BCDR2G, TL431BIDG, and TL431BIDR2G provide ±0.4% tolerance, representing improved accuracy over the original ±1% specification. TL431BVDR2G extends the upper temperature limit to 125°C, supporting high-temperature environments.

For Extended Temperature Range: TL431AIDT from STMicroelectronics combines ±1% tolerance with -40°C to 105°C operating range and reduced cathode current (700 µA), offering superior thermal performance and lower power consumption compared to the original LM431BCM.

Compliance Considerations: All substitute parts maintain REACH Unaffected status and ROHS3 compliance where specified. Moisture sensitivity level remains at MSL 1 (Unlimited) across all alternatives, ensuring consistent handling requirements.

Frequently Asked Questions (FAQ)

Q: Can TL431 series parts directly replace the LM431BCM? A: Yes, all listed TL431 variants are pin-compatible and electrically compatible within the 8-SOIC package. Tolerance and temperature range differences must be evaluated against application requirements.

Q: What is the difference between ±1%, ±0.4%, and ±2.2% tolerance variants? A: Tolerance specifies the maximum deviation of the output voltage from the nominal 2.495V reference. ±1% allows ±24.95mV deviation, ±0.4% allows ±9.98mV, and ±2.2% allows ±54.89mV. Tighter tolerance (±0.4%) is required for precision voltage regulation; looser tolerance (±2.2%) is acceptable for general-purpose applications.

Q: Does packaging type (Tube vs. Tape & Reel) affect electrical performance? A: No. Packaging type (Tube, Tape & Reel, Cut Tape) affects only handling, storage, and automated assembly compatibility. Electrical specifications remain identical regardless of packaging format.

Q: Why does TL431AIDT have lower cathode current (700 µA vs. 1 mA)? A: Lower cathode current indicates improved power efficiency. This specification difference does not affect functional compatibility but reduces quiescent current draw, beneficial for battery-powered or low-power applications.

Q: Is the LM431BCMX suitable for new designs? A: LM431BCMX is active and available, making it suitable for new designs requiring exact parameter matching to the obsolete LM431BCM. However, TL431 variants offer superior availability and active manufacturer support.

Q: Which substitute part is recommended for industrial temperature range applications? A: TL431BVDR2G (-40°C to 125°C) is recommended for industrial applications requiring extended temperature coverage. TL431AIDT (-40°C to 105°C) is an alternative from STMicroelectronics with equivalent tolerance.

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