TL431BIDG4 Equivalent & Substitute Parts

Part Overview

The TL431BIDG4 is a shunt voltage reference IC manufactured by Texas Instruments, designed for adjustable output voltage regulation in power management applications. This component operates as a precision voltage reference with an adjustable output range from 2.495V to 36V and supports output currents up to 100 mA. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity.

Key Parameters

Parameter	Value
Manufacturer Part Number	TL431BIDG4
Manufacturer	Texas Instruments
Reference Type	Shunt
Output Type	Adjustable
Voltage - Output (Min/Fixed)	2.495V
Voltage - Output (Max)	36V
Current - Output	100 mA
Tolerance	±0.5%
Current - Cathode	700 µA
Operating Temperature	-40°C ~ 85°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the TL431BIDG4 is determined by the following critical parameters:

Mandatory Compatibility Parameters:

Reference Type: Shunt (all substitutes must be shunt-type voltage references)
Output Type: Adjustable (output voltage must be user-adjustable)
Package / Case: 8-SOIC (0.154", 3.90mm Width) (identical physical footprint required)
Mounting Type: Surface Mount (same mounting technology)
Voltage - Output (Min/Fixed): 2.495V or compatible minimum
Voltage - Output (Max): 36V or higher maximum
Current - Output: 100 mA or higher
Operating Temperature Range: Must cover -40°C ~ 85°C minimum

Tolerance and Performance Parameters: Tolerance specifications may vary between substitutes. The TL431BIDG4 specifies ±0.5% tolerance. Substitutes with equal or tighter tolerance (lower percentage) are direct replacements. Substitutes with looser tolerance may be acceptable depending on circuit design requirements.

Cathode Current: The TL431BIDG4 specifies 700 µA cathode current. Substitutes with 1 mA cathode current are functionally compatible in most applications, as this parameter affects bias current requirements rather than core functionality.

Parameter Comparison

Part Number	Manufacturer	Voltage Min (V)	Voltage Max (V)	Current Output (mA)	Tolerance	Cathode Current	Temp Range (°C)	Package	Status	RoHS
TL431BIDG4	Texas Instruments	2.495	36	100	±0.5%	700 µA	-40 ~ 85	8-SOIC	Obsolete	ROHS3
LM431CIM/NOPB	Texas Instruments	2.5	37	100	-0.6%, +0.4%	1 mA	-40 ~ 85	8-SOIC	Active	ROHS3
TL431BID	onsemi	2.495	36	100	±0.4%	1 mA	-40 ~ 85	8-SOIC	Obsolete	Non-compliant
LM431AIM/NOPB	Texas Instruments	2.495	37	100	±2.2%	1 mA	-40 ~ 85	8-SOIC	Active	ROHS3
LM431AIMX/NOPB	Texas Instruments	2.495	37	100	±2.2%	1 mA	-40 ~ 85	8-SOIC	Active	ROHS3
LM431BIM/NOPB	Texas Instruments	2.495	37	100	±1%	1 mA	-40 ~ 85	8-SOIC	Active	ROHS3
KA431DTF	onsemi	2.5	36	100	±2%	1 mA	-25 ~ 85	8-SOIC	Active	ROHS3
LM431AIMX	National Semiconductor	2.5	36	100	±2%	1 mA	-40 ~ 85	8-SOIC	Active	Non-compliant
LM431BCMX	National Semiconductor	2.495	36	100	±1%	1 mA	-25 ~ 85	8-SOIC	Active	Undefined
LM431CIMX	onsemi	2.495	36	100	±0.5%	1 mA	-40 ~ 85	8-SOIC	Active	ROHS3
NCV431AIDR2G	onsemi	2.495	36	100	±1%	1 mA	-40 ~ 125	8-SOIC	Active	ROHS3

Engineering Selection Recommendations

Primary Recommendation: LM431CIMX

The LM431CIMX from onsemi is the most direct functional equivalent to the TL431BIDG4. Both parts share identical tolerance specifications (±0.5%), matching voltage output range (2.495V to 36V), and identical operating temperature range (-40°C to 85°C). The LM431CIMX is currently in active production status, ensuring long-term availability. Both parts are ROHS3 compliant. The only difference is cathode current (1 mA versus 700 µA), which does not affect circuit compatibility in standard applications.

Secondary Recommendation: LM431BIM/NOPB

The LM431BIM/NOPB from Texas Instruments offers tighter tolerance (±1%) compared to the original part's ±0.5%, providing improved voltage regulation accuracy. This part is actively produced and ROHS3 compliant. The extended maximum voltage output (37V versus 36V) provides additional design margin. Cathode current is 1 mA.

Alternative for Automotive Applications: NCV431AIDR2G

The NCV431AIDR2G from onsemi is qualified to AEC-Q100 automotive standards and operates across an extended temperature range (-40°C to 125°C). This part is suitable for applications requiring automotive-grade components. Tolerance is ±1%, and all electrical parameters are compatible with the original part.

Compliance Considerations:

Parts with ROHS3 compliance status are preferred for new designs. The LM431AIMX and LM431BCMX from National Semiconductor have undefined or non-compliant RoHS status and should be avoided for applications requiring regulatory compliance.

Temperature Range Limitation:

The KA431DTF and LM431BCMX have reduced lower temperature limits (-25°C instead of -40°C). These parts are not suitable for applications requiring full -40°C operation.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with looser tolerance than the original TL431BIDG4?

A: Tolerance compatibility depends on circuit design requirements. The TL431BIDG4 specifies ±0.5% tolerance. Substitutes with ±1% or ±2.2% tolerance (LM431AIM/NOPB, LM431AIMX/NOPB, LM431BIM/NOPB, KA431DTF) are electrically compatible but provide less precise voltage regulation. Verify that your circuit design can accommodate the wider tolerance band before selecting these parts.

Q: What is the significance of cathode current differences between parts?

A: The TL431BIDG4 specifies 700 µA cathode current, while most substitutes specify 1 mA. Cathode current represents the bias current required by the reference IC. The 1 mA specification is slightly higher but functionally compatible in standard voltage reference circuits. This parameter affects the external bias resistor selection but does not prevent substitution.

Q: Are all substitute parts available in the same 8-SOIC package?

A: Yes. All listed substitute parts use the 8-SOIC (0.154", 3.90mm Width) package, ensuring identical PCB footprint compatibility with the original TL431BIDG4. No layout modifications are required for package substitution.

Q: Which substitute part offers the best long-term availability?

A: The LM431CIMX and NCV431AIDR2G from onsemi, along with LM431BIM/NOPB and LM431AIMX/NOPB from Texas Instruments, are all in active production status. These parts offer superior long-term availability compared to the obsolete TL431BIDG4. The LM431CIMX is recommended as the primary choice due to matching tolerance and voltage specifications.

Q: Can I use the NCV431AIDR2G in non-automotive applications?

A: Yes. The NCV431AIDR2G is automotive-qualified but functionally suitable for general industrial and consumer applications. Its extended temperature range (-40°C to 125°C) and ±1% tolerance make it a robust choice for demanding environments. Automotive qualification does not restrict use in other applications.

Q: What is the difference between tube and tape & reel packaging options?

A: Tube packaging (LM431CIM/NOPB, LM431AIM/NOPB, LM431BIM/NOPB) is suitable for manual assembly and lower-volume production. Tape & Reel packaging (LM431AIMX/NOPB) is optimized for automated pick-and-place assembly in high-volume manufacturing. Both packaging formats contain identical die and electrical specifications. Select based on your assembly process requirements.

Q: Is the LM431AIMX from National Semiconductor a suitable replacement?

A: The LM431AIMX is electrically compatible but has non-compliant RoHS status and affected REACH status. For new designs or applications requiring regulatory compliance, prefer Texas Instruments or onsemi alternatives with ROHS3 compliance. The National Semiconductor part may be acceptable for legacy system maintenance where compliance requirements are not applicable.

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