LM431ACZXA Equivalent & Substitute Parts

Part Overview

The LM431ACZXA is a shunt voltage reference IC manufactured by onsemi, designed for adjustable voltage regulation applications requiring 2.5V to 36V output capability. This component operates as an adjustable shunt regulator with ±2% tolerance and is packaged in TO-92-3 through-hole format. The part is currently classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and production continuity.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM431ACZXA
Manufacturer	onsemi
Category	Power Management (PMIC)
Reference Type	Shunt
Output Type	Adjustable
Voltage - Output (Min/Fixed)	2.5V
Voltage - Output (Max)	36V
Current - Output	100 mA
Tolerance	±2%
Temperature Coefficient	50ppm/°C Typical
Current - Cathode	1 mA
Operating Temperature	-25°C ~ 85°C (TA)
Mounting Type	Through Hole
Package / Case	TO-226-3, TO-92-3 (TO-226AA) Formed Leads
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution eligibility for the LM431ACZXA is determined by the following critical parameters:

Mandatory Compatibility Parameters:

Reference Type: Shunt (all substitutes must maintain shunt regulation topology)
Output Type: Adjustable (voltage adjustment capability required)
Voltage Range: 2.5V minimum to 36V maximum output capability
Current - Output: 100 mA minimum
Current - Cathode: 1 mA minimum
Mounting Type: Through Hole
Package / Case: TO-92-3 or TO-226-3 compatible form factor

Tolerance and Temperature Considerations: Substitutes with equal or tighter tolerance specifications (±2% or better) are directly compatible. Substitutes with wider tolerance (±2.2%) remain functionally equivalent for applications not requiring precision voltage reference. Operating temperature range variations require application-specific evaluation based on end-use environment.

Product Status Impact: Active status substitutes provide ongoing availability and supply chain continuity. Obsolete status substitutes offer compatibility but may face future availability constraints.

Parameter Comparison

Part Number	Manufacturer	Tolerance	Output Min/Fixed	Output Max	Current Output	Cathode Current	Temp Range	Package	Status
LM431ACZXA	onsemi	±2%	2.5V	36V	100 mA	1 mA	-25°C ~ 85°C	TO-92-3	Obsolete
TL431ACLPRAG	onsemi	±1%	2.495V	36V	100 mA	1 mA	0°C ~ 70°C	TO-92-3	Active
TL431AILPRAG	onsemi	±1%	2.495V	36V	100 mA	1 mA	-40°C ~ 85°C	TO-92-3	Active
TL431AILPRPG	onsemi	±1%	2.495V	36V	100 mA	1 mA	-40°C ~ 85°C	TO-92-3	Obsolete
TL431BCLPRAG	onsemi	±0.4%	2.495V	36V	100 mA	1 mA	0°C ~ 70°C	TO-92-3	Active
TL431BCLPRMG	onsemi	±0.4%	2.495V	36V	100 mA	1 mA	0°C ~ 70°C	TO-92-3	Obsolete
TL431BILPRAG	onsemi	±0.4%	2.495V	36V	100 mA	1 mA	-40°C ~ 85°C	TO-92-3	Active
TL431BVLPRAG	onsemi	±0.4%	2.495V	36V	100 mA	1 mA	-40°C ~ 125°C	TO-92	Obsolete
TL431CLPRAG	onsemi	±2.2%	2.495V	36V	100 mA	1 mA	0°C ~ 70°C	TO-92	Active
TL431CLPRPG	onsemi	±2.2%	2.495V	36V	100 mA	1 mA	0°C ~ 70°C	TO-92	Active
TL431ILPRAG	onsemi	±2.2%	2.495V	36V	100 mA	1 mA	-40°C ~ 85°C	TO-92-3	Active

Engineering Selection Recommendations

Primary Recommendation - Active Status Parts:

For new designs and production continuity, TL431AILPRAG is the preferred substitute. This part maintains onsemi manufacturer continuity, offers superior ±1% tolerance specification, supports the full -40°C to 85°C industrial temperature range, and carries active product status ensuring long-term availability. RoHS3 compliance provides environmental regulatory alignment.

Alternative - Extended Temperature Range:

TL431BVLPRAG provides the widest operating temperature range (-40°C to 125°C) with ±0.4% tolerance precision, suitable for applications requiring extreme thermal performance. Obsolete status requires inventory planning.

Tolerance-Matched Alternatives:

TL431CLPRAG and TL431CLPRPG offer tolerance specifications (±2.2%) comparable to the original LM431ACZXA, with active status and RoHS3 compliance. These parts accommodate applications where the original ±2% specification is acceptable.

High-Precision Option:

TL431BCLPRAG and TL431BILPRAG deliver ±0.4% tolerance for precision voltage reference applications, with TL431BILPRAG supporting -40°C to 85°C operation.

All recommended substitutes maintain identical electrical performance parameters (100 mA output current, 1 mA cathode current, 2.495V to 36V output range) and through-hole mounting compatibility.

Frequently Asked Questions (FAQ)

Q: Can TL431CLPRAG directly replace LM431ACZXA in existing designs?

A: Yes. Both parts share identical output current (100 mA), cathode current (1 mA), voltage range (2.5V to 36V), and TO-92-3 package specifications. The TL431CLPRAG tolerance specification (±2.2%) is marginally wider than the original (±2%), which is acceptable for most applications. Verify application-specific tolerance requirements before substitution.

Q: What is the difference between TL431AILPRAG and TL431ACLPRAG?

A: Both parts feature ±1% tolerance and identical electrical specifications. The primary difference is operating temperature range: TL431AILPRAG supports -40°C to 85°C (industrial range), while TL431ACLPRAG operates 0°C to 70°C (commercial range). Select based on end-use environment requirements.

Q: Why do some substitutes show TO-92 package while others specify TO-92-3?

A: TO-92 and TO-92-3 are compatible through-hole packages with identical pin configurations and lead spacing. TO-92-3 explicitly denotes three-pin configuration. Both are mechanically and electrically interchangeable for this application.

Q: Are obsolete-status parts suitable for production use?

A: Obsolete parts (TL431AILPRPG, TL431BCLPRMG, TL431BVLPRAG) remain functionally equivalent but carry supply chain risk. Current inventory availability is documented, but future procurement may be constrained. Use obsolete parts only when active alternatives are unsuitable for application requirements.

Q: What does RoHS3 compliance mean for this component?

A: RoHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. All active-status TL431 variants carry RoHS3 compliance, supporting environmental regulatory requirements in EU and equivalent markets.

Q: Can I use TL431BCLPRAG (±0.4% tolerance) as a drop-in replacement?

A: Yes. Superior tolerance specifications are backward-compatible. TL431BCLPRAG provides tighter voltage regulation than the original LM431ACZXA, improving circuit performance without design modification. Verify PCB layout and thermal management remain adequate for the substitute part.

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