LM431SACMLX Equivalent & Substitute Parts

Part Overview

The LM431SACMLX is a shunt voltage reference IC manufactured by onsemi, designed for adjustable voltage regulation applications. This component features a 2.5V to 36V adjustable output with ±2% tolerance and 100 mA output current capability in a SOT-89-3 surface mount package. The part is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM431SACMLX
Manufacturer	onsemi
Reference Type	Shunt
Output Type	Adjustable
Voltage - Output (Min/Fixed)	2.5V
Voltage - Output (Max)	36V
Current - Output	100 mA
Tolerance	±2%
Current - Cathode	1 mA
Operating Temperature	-25°C ~ 85°C
Package / Case	TO-243AA (SOT-89-3)
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the LM431SACMLX is determined by the following critical parameters:

Reference Type: Shunt voltage reference architecture
Output Type: Adjustable output voltage capability
Voltage Range: Output voltage minimum of 2.5V and maximum of 36V
Current Rating: 100 mA output current capacity
Package: SOT-89-3 surface mount package (TO-243AA case)
Mounting: Surface mount compatibility

Substitute parts must maintain compatibility across these electrical and mechanical specifications. Texas Instruments TL431 series components meet these requirements with improved tolerance specifications (±1% and ±0.5%) and active product status, providing direct functional equivalence with enhanced performance characteristics.

Parameter Comparison

Part Number	Manufacturer	Tolerance	Output Voltage (Min/Max)	Output Current	Cathode Current	Operating Temperature	Product Status	Package
LM431SACMLX	onsemi	±2%	2.5V / 36V	100 mA	1 mA	-25°C ~ 85°C	Obsolete	SOT-89-3
TL431ACPK	Texas Instruments	±1%	2.495V / 36V	100 mA	600 µA	0°C ~ 70°C	Active	SOT-89-3
TL431AIPK	Texas Instruments	±1%	2.495V / 36V	100 mA	700 µA	-40°C ~ 85°C	Active	SOT-89-3
TL431BCPK	Texas Instruments	±0.5%	2.495V / 36V	100 mA	600 µA	0°C ~ 70°C	Active	SOT-89-3
TL431BIPK	Texas Instruments	±0.5%	2.495V / 36V	100 mA	700 µA	-40°C ~ 85°C	Active	SOT-89-3
TL431BQPK	Texas Instruments	±0.5%	2.495V / 36V	100 mA	700 µA	-40°C ~ 125°C	Active	SOT-89-3

Engineering Selection Recommendations

Primary Substitutes for Standard Applications:

TL431AIPK and TL431BIPK are the preferred direct replacements for the LM431SACMLX. Both parts are active products from Texas Instruments with SOT-89-3 packaging, matching the original component's mechanical footprint. TL431AIPK provides ±1% tolerance with -40°C to 85°C operating range, while TL431BIPK offers improved ±0.5% tolerance across the same temperature range. Both support the full 100 mA output current requirement.

For Extended Temperature Applications:

TL431BQPK extends the operating temperature range to -40°C to 125°C with ±0.5% tolerance, suitable for applications requiring higher temperature performance than the original LM431SACMLX specification.

For Standard Temperature Range Applications:

TL431ACPK and TL431BCPK operate within 0°C to 70°C, providing ±1% and ±0.5% tolerance respectively. These parts are appropriate for controlled environment applications where the reduced temperature range is acceptable.

All recommended substitutes carry ROHS3 compliance and REACH unaffected status, meeting modern regulatory requirements. Obsolete packaging variants (PKG3 designations with Tape & Reel packaging) are available but should be avoided for new designs due to discontinued product status.

Frequently Asked Questions (FAQ)

Q: Can TL431 series parts directly replace the LM431SACMLX without circuit modifications?

A: Yes. All recommended TL431 substitutes maintain identical shunt reference architecture, SOT-89-3 package pinout, and electrical operating parameters (2.5V to 36V adjustable output, 100 mA output current). Circuit board layout and component placement require no changes.

Q: What is the difference between TL431AIPK and TL431BIPK?

A: Both parts share identical operating temperature range (-40°C to 85°C) and SOT-89-3 packaging. The primary difference is tolerance specification: TL431AIPK provides ±1% accuracy while TL431BIPK provides ±0.5% accuracy. Selection depends on circuit accuracy requirements.

Q: Why does the LM431SACMLX specify 1 mA cathode current while TL431 parts specify 600-700 µA?

A: Both specifications fall within acceptable operating ranges for shunt voltage reference applications. The lower cathode current in TL431 parts represents improved efficiency without affecting functional compatibility or circuit performance.

Q: Are tape and reel (PKG3) variants suitable for production use?

A: Tape and reel variants (TL431ACPKG3, TL431AIPKG3, TL431BCPKG3, TL431BIPKG3, TL431AQPKG3) are classified as obsolete products. For new designs and ongoing production, use active product variants with cut tape or digi-reel packaging (ACPK, AIPK, BCPK, BIPK, BQPK designations).

Q: Which substitute part best matches the original LM431SACMLX temperature range?

A: TL431AIPK and TL431BIPK both support -40°C to 85°C operation, encompassing the original -25°C to 85°C specification. TL431BQPK extends this to -40°C to 125°C for applications requiring higher temperature capability.

Q: Do all substitute parts meet current regulatory compliance requirements?

A: Yes. All active TL431 variants carry ROHS3 compliance and REACH unaffected status, meeting current environmental and regulatory standards for component procurement and use.

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