TL431BCDG Equivalent & Substitute Parts

Part Overview

The TL431BCDG is a shunt voltage reference IC manufactured by onsemi, designed for adjustable voltage regulation applications. This component features a 2.495V adjustable output with ±0.4% tolerance and supports output currents up to 100 mA across a 36V range. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. Substitute parts must maintain functional compatibility while meeting the electrical and mechanical requirements of the original design.

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	±0.4%
Temperature Coefficient	50ppm/°C Typical
Current - Cathode	1 mA
Operating Temperature	0°C ~ 70°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the TL431BCDG is determined by the following critical parameters:

Mandatory Compatibility Criteria:

Reference Type: Shunt (all candidates meet this requirement)
Output Type: Adjustable (all candidates meet this requirement)
Package / Case: 8-SOIC form factor (all candidates meet this requirement)
Voltage Range: 36V maximum output (all candidates meet this requirement)
Current - Output: 100 mA (all candidates meet this requirement)
Current - Cathode: 1 mA (all candidates meet this requirement)
Mounting Type: Surface Mount (all candidates meet this requirement)

Tolerance and Performance Considerations: Substitute parts are grouped based on tolerance specifications. The TL431BCDG specifies ±0.4% tolerance. Parts with equal or tighter tolerance (±0.4% or better) are direct equivalents. Parts with looser tolerance (±0.5%, ±1%, ±2%) are functional substitutes where tolerance relaxation is acceptable.

Temperature Range Considerations: The TL431BCDG operates from 0°C to 70°C. Substitute parts with extended temperature ranges provide additional operational flexibility but remain compatible within the original specification window.

Parameter Comparison

Part Number	Manufacturer	Tolerance	Voltage Output (Min)	Voltage Output (Max)	Current Output	Temperature Range	Product Status	RoHS Status
TL431BCDG	onsemi	±0.4%	2.495V	36V	100 mA	0°C ~ 70°C	Obsolete	ROHS3 Compliant
KA431DTF	onsemi	±2%	2.5V	36V	100 mA	-25°C ~ 85°C	Active	ROHS3 Compliant
LM431AIMX	National Semiconductor	±2%	2.5V	36V	100 mA	-40°C ~ 85°C	Active	RoHS non-compliant
LM431BCMX	National Semiconductor	±1%	2.495V	36V	100 mA	-25°C ~ 85°C	Active	Vendor Undefined
LM431CIMX	onsemi	±0.5%	2.495V	36V	100 mA	-40°C ~ 85°C	Active	ROHS3 Compliant
TL1431CD	STMicroelectronics	±0.4%	2.5V	36V	100 mA	-20°C ~ 70°C	Obsolete	ROHS3 Compliant
TL1431CDR	Texas Instruments	±0.4%	2.5V	36V	100 mA	0°C ~ 70°C	Active	ROHS3 Compliant
TL1431MDREP	Texas Instruments	±0.4%	2.5V	36V	100 mA	-55°C ~ 125°C	Active	ROHS3 Compliant
TL1431QD	Texas Instruments	±0.4%	2.5V	36V	100 mA	-40°C ~ 125°C	Active	ROHS3 Compliant
TL1431QDR	Texas Instruments	±0.4%	2.5V	36V	100 mA	-40°C ~ 125°C	Active	ROHS3 Compliant
TL1431QDREP	Texas Instruments	±0.4%	2.5V	36V	100 mA	-40°C ~ 125°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalents (±0.4% Tolerance, Active Status): TL1431CDR, TL1431MDREP, TL1431QD, TL1431QDR, and TL1431QDREP are direct functional equivalents with matching ±0.4% tolerance. All are manufactured by Texas Instruments and carry active product status with ROHS3 compliance. These parts are recommended as primary replacements for the obsolete TL431BCDG. TL1431MDREP and TL1431QD/QDR/QDREP offer extended temperature ranges (-55°C to 125°C and -40°C to 125°C respectively), providing additional operational margin beyond the original 0°C to 70°C specification.

Tighter Tolerance Alternative (±0.5%): LM431CIMX provides ±0.5% tolerance, which exceeds the original ±0.4% specification. This part is manufactured by onsemi, carries active product status, and is ROHS3 compliant. The extended temperature range (-40°C to 85°C) offers improved operational flexibility.

Tolerance-Relaxed Alternatives: LM431BCMX (±1% tolerance) and KA431DTF (±2% tolerance) are functional substitutes where tolerance relaxation is acceptable. LM431BCMX maintains the 2.495V minimum output voltage matching the original part. KA431DTF shifts to 2.5V minimum output. Both are active products with extended temperature ranges.

Compliance Considerations: All recommended direct equivalents maintain ROHS3 compliance. LM431AIMX carries RoHS non-compliance status and should be avoided in applications requiring regulatory compliance. LM431BCMX shows vendor-undefined MSL status and requires verification for moisture-sensitive applications.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with looser tolerance than the original TL431BCDG? A: Tolerance substitution depends on circuit requirements. The TL431BCDG specifies ±0.4%. Parts with ±0.5%, ±1%, or ±2% tolerance are electrically compatible but introduce greater output voltage variation. Circuit design margins must accommodate the relaxed tolerance before substitution.

Q: What is the difference between TL1431CDR and TL1431QDREP? A: Both parts share ±0.4% tolerance and 100 mA output current. TL1431CDR operates from 0°C to 70°C, matching the original TL431BCDG temperature range. TL1431QDREP extends to -40°C to 125°C, providing wider operational temperature coverage. Packaging differs: TL1431CDR uses Tape & Reel format, while TL1431QDREP uses Tape & Reel with Digi-Reel option.

Q: Are all substitute parts in 8-SOIC package? A: Yes. All listed substitute parts use the 8-SOIC (0.154", 3.90mm Width) package, ensuring mechanical and electrical compatibility with the original TL431BCDG footprint.

Q: Which substitute part offers the best long-term availability? A: Texas Instruments TL1431 series parts (TL1431CDR, TL1431MDREP, TL1431QD, TL1431QDR, TL1431QDREP) carry active product status, indicating ongoing manufacturing and distribution support. These are preferred over obsolete alternatives for new designs and long-term production.

Q: Is RoHS compliance required for my application? A: If RoHS3 compliance is mandatory, select from TL1431CDR, TL1431MDREP, TL1431QD, TL1431QDR, TL1431QDREP, KA431DTF, or LM431CIMX. Avoid LM431AIMX (RoHS non-compliant) and verify LM431BCMX status with your supplier.

Q: Can I substitute the TL431BCDG with KA431DTF in a precision voltage reference circuit? A: KA431DTF tolerance is ±2%, compared to TL431BCDG's ±0.4%. This 5x tolerance increase may exceed precision circuit requirements. Evaluate circuit tolerance budgets before substitution. For precision applications, LM431CIMX (±0.5%) or direct equivalents with ±0.4% tolerance are more appropriate.

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