TL431BCD Equivalent & Substitute Parts

Part Overview

The TL431BCD is a shunt voltage reference IC manufactured by onsemi, designed for adjustable voltage regulation applications. It provides a fixed output voltage of 2.495V with a maximum output of 36V, delivering up to 100 mA of output current. The device operates across a 0°C to 70°C temperature range and is packaged in an 8-SOIC surface mount configuration.

The TL431BCD is currently classified as obsolete. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support long-term product availability for applications requiring shunt voltage reference functionality.

Key Parameters

Parameter	Value
Manufacturer Part Number	TL431BCD
Manufacturer	onsemi
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	50 ppm/°C Typical
Operating Temperature	0°C ~ 70°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Current - Cathode	1 mA
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the TL431BCD is determined by strict alignment of the following electrical and mechanical parameters:

Critical Substitution Parameters:

Reference Type: Shunt (all substitutes must be shunt-type voltage references)
Output Type: Adjustable (all substitutes must support adjustable output voltage)
Package / Case: 8-SOIC (0.154", 3.90mm Width) (all substitutes must use identical surface mount package)
Voltage - Output (Max): 36V (all substitutes must support maximum output voltage of 36V or greater)
Current - Output: 100 mA (all substitutes must support 100 mA output current)
Current - Cathode: 1 mA (all substitutes must support 1 mA cathode current)
Mounting Type: Surface Mount (all substitutes must be surface mount)

Tolerance and Temperature Considerations: Substitutes may vary in tolerance specification (±0.4%, ±0.5%, ±1%, ±2%) and operating temperature range. Selection depends on application requirements for voltage accuracy and thermal operating conditions.

Parameter Comparison

Part Number	Manufacturer	Voltage Output (Min)	Voltage Output (Max)	Current Output	Tolerance	Temp Coefficient	Operating Temp	Product Status	RoHS Status
TL431BCD	onsemi	2.495V	36V	100 mA	±0.4%	50 ppm/°C	0°C ~ 70°C	Obsolete	RoHS non-compliant
KA431DTF	onsemi	2.5V	36V	100 mA	±2%	50 ppm/°C	-25°C ~ 85°C	Active	ROHS3 Compliant
LM431AIMX	National Semiconductor	2.5V	36V	100 mA	±2%	50 ppm/°C	-40°C ~ 85°C	Active	RoHS non-compliant
LM431BCMX	National Semiconductor	2.495V	36V	100 mA	±1%	50 ppm/°C	-25°C ~ 85°C	Active	Vendor Undefined
LM431CIMX	onsemi	2.495V	36V	100 mA	±0.5%	50 ppm/°C	-40°C ~ 85°C	Active	ROHS3 Compliant
TL1431CD	STMicroelectronics	2.5V	36V	100 mA	±0.4%	90 ppm/°C	-20°C ~ 70°C	Obsolete	ROHS3 Compliant
TL1431CDR	Texas Instruments	2.5V	36V	100 mA	±0.4%	Not specified	0°C ~ 70°C	Active	ROHS3 Compliant
TL1431MDREP	Texas Instruments	2.5V	36V	100 mA	±0.4%	Not specified	-55°C ~ 125°C	Active	ROHS3 Compliant
TL1431QD	Texas Instruments	2.5V	36V	100 mA	±0.4%	Not specified	-40°C ~ 125°C	Active	ROHS3 Compliant
TL1431QDR	Texas Instruments	2.5V	36V	100 mA	±0.4%	Not specified	-40°C ~ 125°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Substitutes (Active Product Status):

For applications requiring immediate replacement of the obsolete TL431BCD, the following parts are recommended based on active product status and compliance certifications:

TL1431CDR, TL1431MDREP, TL1431QD, and TL1431QDR are all manufactured by Texas Instruments and maintain active product status. These parts share the ±0.4% tolerance specification of the original TL431BCD and are ROHS3 compliant. TL1431CDR operates within the original temperature range (0°C ~ 70°C), while TL1431MDREP and TL1431QD/TL1431QDR extend the operating temperature range to -55°C ~ 125°C and -40°C ~ 125°C respectively, providing enhanced thermal performance for demanding applications.

LM431CIMX, manufactured by onsemi, offers ±0.5% tolerance with ROHS3 compliance and an extended operating temperature range of -40°C ~ 85°C. This part provides a closer tolerance match to the original specification than alternatives with ±1% or ±2% tolerance.

Alternative Substitutes (Relaxed Tolerance Requirements):

For applications where voltage accuracy requirements are less stringent, KA431DTF and LM431AIMX provide active product status with ±2% tolerance. KA431DTF is ROHS3 compliant with an operating range of -25°C ~ 85°C. LM431AIMX extends the lower temperature limit to -40°C but is RoHS non-compliant.

LM431BCMX offers ±1% tolerance with active product status and an operating range of -25°C ~ 85°C, representing a middle ground between the original ±0.4% specification and the ±2% alternatives.

Compliance Considerations:

All recommended active substitutes are ROHS3 compliant except LM431AIMX. For applications requiring RoHS compliance, select from TL1431CDR, TL1431MDREP, TL1431QD, TL1431QDR, KA431DTF, or LM431CIMX.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with different tolerance than the TL431BCD?

A: Yes, if your application permits. The TL431BCD specifies ±0.4% tolerance. Substitutes with ±0.5%, ±1%, or ±2% tolerance are electrically compatible but will exhibit greater voltage variation. Verify that your circuit design accommodates the relaxed tolerance before selection.

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

A: Yes. All listed substitutes use the 8-SOIC (0.154", 3.90mm Width) surface mount package, ensuring mechanical and electrical compatibility with existing PCB layouts designed for the TL431BCD.

Q: What is the difference between TL1431QD and TL1431QDR?

A: Both parts are identical in electrical specifications and operating temperature range (-40°C ~ 125°C). The difference is packaging: TL1431QD is supplied in Tube packaging, while TL1431QDR is supplied in Cut Tape (CT) & Digi-Reel® format. Select based on your assembly process requirements.

Q: Which substitute offers the widest operating temperature range?

A: TL1431MDREP, TL1431QD, and TL1431QDR all support -40°C to -55°C minimum temperatures and 125°C maximum, compared to the original TL431BCD range of 0°C ~ 70°C. These parts are suitable for extended thermal applications.

Q: Is RoHS compliance required for my application?

A: If RoHS compliance is mandatory, avoid LM431AIMX and the original TL431BCD. Select from TL1431CDR, TL1431MDREP, TL1431QD, TL1431QDR, KA431DTF, or LM431CIMX, all of which are ROHS3 compliant.

Q: Can I substitute a part with lower tolerance (e.g., ±0.4%) for one with higher tolerance (e.g., ±2%)?

A: Yes. A part with lower tolerance will perform within the specifications of a design requiring higher tolerance. However, this may result in unnecessary cost. Verify that the lower-tolerance part is available and cost-effective before substitution.

Q: What is the minimum cathode current requirement?

A: All listed substitutes maintain the 1 mA cathode current specification of the original TL431BCD. This parameter is consistent across all alternatives and does not affect substitution decisions.

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