LM431SBCMLX Equivalent & Substitute Parts

Part Overview

The LM431SBCMLX is a shunt voltage reference IC manufactured by onsemi, designed for adjustable voltage regulation applications. This component operates with an adjustable output range of 2.495V to 36V, delivering up to 100 mA output current with ±1% tolerance. The device is packaged in SOT-89-3 (TO-243AA) surface mount configuration.

The LM431SBCMLX carries an obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this reference voltage IC.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM431SBCMLX
Manufacturer	onsemi
Reference Type	Shunt
Output Type	Adjustable
Voltage - Output (Min/Fixed)	2.495V
Voltage - Output (Max)	36V
Current - Output	100 mA
Tolerance	±1%
Temperature Coefficient	50 ppm/°C Typical
Current - Cathode	1 mA
Operating Temperature	-25°C ~ 85°C (TA)
Package / Case	TO-243AA
Supplier Device Package	SOT-89-3
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the LM431SBCMLX is determined by the following critical parameters:

Reference Type: Shunt voltage reference
Output Type: Adjustable
Voltage Output Range: 2.495V to 36V
Output Current: 100 mA
Tolerance: ±1%
Package: SOT-89-3 (TO-243AA)
Mounting Type: Surface Mount

Substitute parts must maintain identical or compatible electrical specifications across these parameters. Variations in cathode current, operating temperature range, and tolerance grade are secondary considerations that may affect circuit performance but do not prevent functional substitution when the primary parameters align.

Parameter Comparison

Part Number	Manufacturer	Voltage Output (Min/Max)	Current Output	Tolerance	Package	Operating Temp	Cathode Current	Product Status
LM431SBCMLX	onsemi	2.495V / 36V	100 mA	±1%	SOT-89-3	-25°C ~ 85°C	1 mA	Obsolete
LM431SBCMFX	onsemi	2.495V / 36V	100 mA	±1%	SOT-23F-3	-25°C ~ 85°C	1 mA	Active
TL431ACPK	Texas Instruments	2.495V / 36V	100 mA	±1%	SOT-89-3	0°C ~ 70°C	600 µA	Active
TL431ACPKG3	Texas Instruments	2.495V / 36V	100 mA	±1%	SOT-89-3	0°C ~ 70°C	600 µA	Obsolete
TL431AIPK	Texas Instruments	2.495V / 36V	100 mA	±1%	SOT-89-3	-40°C ~ 85°C	700 µA	Active
TL431AIPKG3	Texas Instruments	2.495V / 36V	100 mA	±1%	SOT-89-3	-40°C ~ 85°C	700 µA	Obsolete
TL431AQPK	Texas Instruments	2.495V / 36V	100 mA	±1%	SOT-89-3	-40°C ~ 125°C	700 µA	Active
TL431AQPKG3	Texas Instruments	2.495V / 36V	100 mA	±1%	SOT-89-3	-40°C ~ 125°C	700 µA	Obsolete
TL431BCPK	Texas Instruments	2.495V / 36V	100 mA	±0.5%	SOT-89-3	0°C ~ 70°C	600 µA	Active
TL431BCPKG3	Texas Instruments	2.495V / 36V	100 mA	±0.5%	SOT-89-3	0°C ~ 70°C	600 µA	Obsolete
TL431BIPK	Texas Instruments	2.495V / 36V	100 mA	±0.5%	SOT-89-3	-40°C ~ 85°C	700 µA	Active

Engineering Selection Recommendations

For applications currently using the obsolete LM431SBCMLX, the following active-status alternatives are recommended based on compliance and availability:

Primary Recommendation: TL431AIPK (Texas Instruments) This part maintains identical electrical specifications (2.495V to 36V output, 100 mA, ±1% tolerance) in the same SOT-89-3 package. Operating temperature range extends to -40°C, providing broader environmental coverage than the original part. Both components are ROHS3 compliant and carry identical REACH and ECCN classifications.

Alternative: TL431AQPK (Texas Instruments) Offers the widest operating temperature range (-40°C to 125°C) while maintaining all core electrical parameters. Suitable for applications requiring extended temperature performance. ROHS3 compliant with matching regulatory certifications.

Package Variant: LM431SBCMFX (onsemi) Maintains onsemi manufacturer continuity with identical electrical specifications and operating temperature range. Differs only in package format (SOT-23F-3 flat leads versus SOT-89-3). Appropriate when PCB layout accommodates the alternative package geometry. Active product status ensures ongoing availability.

Higher Precision Option: TL431BCPK or TL431BIPK (Texas Instruments) These parts offer improved tolerance specification (±0.5% versus ±1%), providing enhanced voltage regulation accuracy. Electrical output range and current ratings remain identical. Suitable for applications requiring tighter voltage reference precision.

All recommended substitutes maintain ROHS3 compliance, unlimited moisture sensitivity rating (MSL 1 or equivalent), and are unaffected by REACH regulations, ensuring regulatory alignment with the original component.

Frequently Asked Questions (FAQ)

Q: Can TL431 series parts directly replace the LM431SBCMLX? A: Yes, when electrical specifications align. TL431AIPK, TL431AQPK, TL431ACPK, and TL431BIPK all maintain the required 2.495V to 36V output range, 100 mA current capacity, and SOT-89-3 package format. Verify operating temperature requirements and tolerance specifications for your specific application.

Q: What is the difference between ±1% and ±0.5% tolerance variants? A: Tolerance specification defines the maximum deviation of output voltage from the nominal 2.495V reference. ±1% tolerance allows ±24.95 mV deviation, while ±0.5% tolerance limits deviation to ±12.48 mV. Applications requiring tighter voltage regulation should specify ±0.5% variants (TL431BCPK, TL431BIPK).

Q: Does cathode current variation affect substitution compatibility? A: Cathode current (1 mA for LM431SBCMLX versus 600-700 µA for TL431 variants) represents the minimum operating current through the reference element. Lower cathode current in TL431 parts reduces power dissipation and may improve circuit efficiency. This difference does not prevent functional substitution but should be evaluated in bias network design.

Q: Why is LM431SBCMFX listed as a substitute if it uses a different package? A: LM431SBCMFX maintains identical electrical specifications and operating characteristics as the LM431SBCMLX, differing only in package format (SOT-23F-3 flat leads versus SOT-89-3). This variant is suitable for designs where PCB layout can accommodate the alternative package geometry, providing supply continuity within the onsemi product line.

Q: Are all substitute parts ROHS3 compliant? A: Yes. All listed substitute parts carry ROHS3 compliance certification, matching the regulatory status of the original LM431SBCMLX. All parts are unaffected by REACH regulations and classified under ECCN EAR99.

Q: What operating temperature range should I select? A: The original LM431SBCMLX operates from -25°C to 85°C. TL431AIPK and TL431AQPK extend this range to -40°C and -40°C to 125°C respectively. Select based on your application's environmental requirements. Narrower range variants (TL431ACPK, TL431BCPK: 0°C to 70°C) are suitable for controlled indoor environments.

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