TL431BQLPE3 Equivalent & Substitute Parts

Part Overview

The TL431BQLPE3 is a shunt voltage reference IC manufactured by Texas Instruments, designed for adjustable voltage regulation applications. This component provides a fixed output voltage of 2.495V with a maximum output of 36V, capable of delivering 100 mA with ±0.5% tolerance. The device operates across a temperature range of -40°C to 125°C and is housed in a TO-92-3 through-hole package. The TL431BQLPE3 is classified as obsolete, making equivalent substitute parts necessary for ongoing production and maintenance applications. Alternative components from active product lines offer comparable electrical characteristics while maintaining design compatibility.

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	±0.5%
Current - Cathode	700 µA
Operating Temperature	-40°C ~ 125°C
Mounting Type	Through Hole
Package / Case	TO-92-3
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the TL431BQLPE3 is determined by strict electrical and mechanical compatibility criteria. The primary substitution parameters are:

Electrical Compatibility Requirements:

Reference type must be shunt
Output type must be adjustable
Output voltage range must encompass 2.495V minimum and 36V maximum
Current output capability must be 100 mA or greater
Tolerance must be ±0.5% or better (lower tolerance values are acceptable)
Operating temperature range must cover or exceed -40°C to 125°C

Mechanical Compatibility Requirements:

Mounting type must be through hole
Package must be TO-92-3 or equivalent form factor

Substitute parts are grouped into two categories: direct replacements with identical or superior electrical specifications, and functional equivalents with acceptable tolerance variations. All listed substitutes maintain the core shunt reference architecture and adjustable output configuration required for circuit compatibility.

Parameter Comparison

Part Number	Manufacturer	Voltage Output (Min)	Voltage Output (Max)	Current Output	Tolerance	Cathode Current	Operating Temp	Package	Status
TL431BQLPE3	Texas Instruments	2.495V	36V	100 mA	±0.5%	700 µA	-40°C ~ 125°C	TO-92-3	Obsolete
KA431AZBU	Fairchild Semiconductor	2.495V	36V	100 mA	±1%	1 mA	-25°C ~ 85°C	TO-92-3	Active
TL1431ACZ	STMicroelectronics	2.5V	36V	100 mA	±0.25%	600 µA	-20°C ~ 70°C	TO-92-3	Active
TL1431IZ	STMicroelectronics	2.5V	36V	100 mA	±0.4%	1 mA	-40°C ~ 105°C	TO-92-3	Active
TL431ACLPG	onsemi	2.495V	36V	100 mA	±1%	1 mA	0°C ~ 70°C	TO-92-3	Active
TL431ACZ	Fairchild Semiconductor	2.495V	36V	100 mA	±1%	600 µA	0°C ~ 70°C	TO-92-3	Obsolete
TL431AILPG	onsemi	2.495V	36V	100 mA	±1%	1 mA	-40°C ~ 85°C	TO-92-3	Active
TL431AIZ	STMicroelectronics	2.495V	36V	100 mA	±1%	700 µA	-40°C ~ 105°C	TO-92-3	Active
TL431BCLPG	onsemi	2.495V	36V	100 mA	±0.4%	1 mA	0°C ~ 70°C	TO-92-3	Obsolete
TL431BFDT,215	Nexperia USA Inc.	2.495V	36V	100 mA	±0.5%	600 µA	-40°C ~ 125°C	TO-236AB	Active
TL431BILPG	onsemi	2.495V	36V	100 mA	±0.4%	1 mA	-40°C ~ 85°C	TO-92-3	Active

Engineering Selection Recommendations

Primary Recommendation for Through-Hole TO-92-3 Applications:

TL431AIZ (STMicroelectronics) is the preferred substitute for the obsolete TL431BQLPE3. This component maintains identical electrical specifications for voltage output range (2.495V to 36V) and current capacity (100 mA), with ±1% tolerance that remains within acceptable design margins. The operating temperature range of -40°C to 105°C covers the original specification, and the device is in active production status with extensive inventory availability (389,850 units). RoHS3 compliance and REACH unaffected status ensure regulatory compatibility.

Alternative for Enhanced Tolerance Requirements:

TL1431ACZ (STMicroelectronics) offers superior tolerance performance at ±0.25%, providing tighter voltage regulation for precision applications. This device maintains the 2.5V to 36V output range and 100 mA current capacity. The operating temperature range of -20°C to 70°C is narrower than the original specification and should be evaluated against application requirements. Active product status and RoHS3 compliance are confirmed.

Surface Mount Alternative:

TL431BFDT,215 (Nexperia USA Inc.) provides an equivalent electrical specification with ±0.5% tolerance and -40°C to 125°C operating range matching the original device. This component is housed in a TO-236AB (SOT-23-3) surface mount package and includes AEC-Q100 automotive qualification. Selection of this variant requires PCB redesign for surface mount compatibility.

Secondary Through-Hole Options:

TL431BILPG (onsemi) and TL431AILPG (onsemi) are active production alternatives with ±0.4% and ±1% tolerance respectively, both in TO-92-3 through-hole packages. These components support the full -40°C to 85°C operating range and maintain 100 mA output capacity.

All recommended substitutes are RoHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can the TL431BQLPE3 be directly replaced with any of the listed substitutes?

A: Direct replacement is possible only with components maintaining identical or superior electrical specifications within the same through-hole package. TL431AIZ, TL431AILPG, and TL431BILPG are direct pin-compatible replacements in TO-92-3 packages. Surface mount alternatives such as TL431BFDT,215 require circuit board redesign.

Q: What is the significance of tolerance differences between the original part and substitutes?

A: The TL431BQLPE3 specifies ±0.5% tolerance. Substitutes with ±1% tolerance (KA431AZBU, TL431ACLPG, TL431ACZ, TL431AILPG, TL431AIZ) provide acceptable alternatives for most applications where voltage regulation margin is sufficient. Substitutes with ±0.25% or ±0.4% tolerance (TL1431ACZ, TL1431IZ, TL431BCLPG, TL431BILPG) offer enhanced precision for demanding applications.

Q: Are there temperature range limitations when substituting the TL431BQLPE3?

A: The original device operates from -40°C to 125°C. Most active substitutes support -40°C to 85°C or -40°C to 105°C ranges, which cover typical industrial and commercial applications. TL1431ACZ operates only to 70°C and should be selected only when application temperature requirements do not exceed this limit. TL431BFDT,215 maintains the full -40°C to 125°C range.

Q: What is the difference between cathode current specifications across substitute parts?

A: Cathode current values (600 µA to 1 mA) represent the minimum operating current required for proper device function. These variations are within acceptable design margins for shunt reference applications. Circuit design should ensure minimum cathode current is supplied through the reference load path.

Q: Can the surface mount TL431BFDT,215 be used as a direct replacement?

A: The TL431BFDT,215 is electrically equivalent but housed in a TO-236AB (SOT-23-3) surface mount package, whereas the original TL431BQLPE3 uses a through-hole TO-92-3 package. Substitution requires PCB redesign and is not a direct pin-for-pin replacement. This option is suitable only for new designs or board revisions.

Q: Which substitute offers the best combination of availability and specification match?

A: TL431AIZ from STMicroelectronics provides the optimal balance of electrical compatibility, active production status, and inventory availability (389,850 units in stock). This component matches the original voltage specifications, maintains adequate tolerance performance, and supports the full temperature range required for most applications.

Q: Are all listed substitutes RoHS3 compliant?

A: All active production substitutes listed are RoHS3 compliant. Obsolete parts (TL431ACZ from Fairchild Semiconductor and TL431BCLPG from onsemi) also carry RoHS3 compliance certification. Compliance status should be confirmed with the specific supplier for procurement.

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