TL431BQLPME3 Equivalent & Substitute Parts

Part Overview

The TL431BQLPME3 is a shunt voltage reference IC manufactured by Texas Instruments, designed for adjustable voltage regulation applications. This component provides a fixed reference voltage of 2.495V with a maximum output of 36V and supports output currents up to 100 mA. The device is packaged in TO-92-3 (TO-226-3) through-hole configuration and operates across the industrial temperature range of -40°C to 125°C.

The TL431BQLPME3 is classified as obsolete, which necessitates identification of active equivalent and substitute parts for new designs and ongoing production requirements. Suitable alternatives must maintain electrical compatibility across critical parameters including output voltage range, current capacity, tolerance specifications, and mechanical packaging.

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 (TA)
Mounting Type	Through Hole
Package / Case	TO-226-3, TO-92-3 (TO-226AA) Formed Leads
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution compatibility for the TL431BQLPME3 is determined by the following critical electrical and mechanical parameters:

Primary Compatibility Criteria:

Reference type (Shunt)
Output type (Adjustable)
Output voltage range (minimum 2.495V to 2.5V, maximum 36V)
Output current capacity (100 mA)
Tolerance specification (±0.5% or tighter)
Package type (TO-92-3 or TO-92 through-hole)
Operating temperature range (-40°C to 125°C minimum)
Cathode current specifications

Substitute parts are grouped into two categories based on tolerance and cathode current characteristics:

Group 1 - Direct Equivalents (±0.5% Tolerance):

TL431BQLPM (Texas Instruments) - Active status, identical electrical specifications
AS431AZTR-E1 (Diodes Incorporated) - Active status, 2.5V output, ±0.5% tolerance
AS431IAZTR-G1 (Diodes Incorporated) - Active status, 2.5V output, ±0.5% tolerance, 50 µA cathode current

Group 2 - Relaxed Tolerance Alternatives (±0.4% to ±1%):

AS431AZTR-G1 (Diodes Incorporated) - Active status, ±0.5% tolerance
AS431BZTR-E1 (Diodes Incorporated) - Active status, ±1% tolerance
AS431BZTR-G1 (Diodes Incorporated) - Active status, ±1% tolerance
AZ431AZ-ATRE1 (Diodes Incorporated) - Active status, ±0.4% tolerance
AZ431AZ-ATRG1 (Diodes Incorporated) - Active status, ±0.4% tolerance
AZ431BZ-ATRE1 (Diodes Incorporated) - Active status, ±0.8% tolerance
KA431AZTA (onsemi) - Active status, ±1% tolerance, 2.495V output

Parameter Comparison

Part Number	Manufacturer	Status	Output (Min/Fixed)	Output (Max)	Current Output	Tolerance	Cathode Current	Temp Range	Package
TL431BQLPME3	Texas Instruments	Obsolete	2.495V	36V	100 mA	±0.5%	700 µA	-40°C ~ 125°C	TO-92-3
TL431BQLPM	Texas Instruments	Active	2.495V	36V	100 mA	±0.5%	700 µA	-40°C ~ 125°C	TO-92-3
AS431AZTR-E1	Diodes Incorporated	Active	2.5V	36V	100 mA	±0.5%	1 mA	-40°C ~ 125°C	TO-92
AS431AZTR-G1	Diodes Incorporated	Active	2.5V	36V	100 mA	±0.5%	1 mA	-40°C ~ 125°C	TO-92
AS431BZTR-E1	Diodes Incorporated	Active	2.5V	36V	100 mA	±1%	1 mA	-40°C ~ 125°C	TO-92
AS431BZTR-G1	Diodes Incorporated	Active	2.5V	36V	100 mA	±1%	1 mA	-40°C ~ 125°C	TO-92
AS431IAZTR-G1	Diodes Incorporated	Active	2.5V	36V	100 mA	±0.5%	50 µA	-40°C ~ 125°C	TO-92
AZ431AZ-ATRE1	Diodes Incorporated	Active	2.5V	36V	100 mA	±0.4%	1 mA	-40°C ~ 125°C	TO-92
AZ431AZ-ATRG1	Diodes Incorporated	Active	2.5V	36V	100 mA	±0.4%	1 mA	-40°C ~ 125°C	TO-92
AZ431BZ-ATRE1	Diodes Incorporated	Active	2.5V	36V	100 mA	±0.8%	1 mA	-40°C ~ 125°C	TO-92
KA431AZTA	onsemi	Active	2.495V	36V	100 mA	±1%	1 mA	-25°C ~ 85°C	TO-92-3

Engineering Selection Recommendations

Primary Recommendation: TL431BQLPM

The TL431BQLPM from Texas Instruments is the direct active equivalent to the obsolete TL431BQLPME3. This part maintains identical electrical specifications including 2.495V minimum output voltage, ±0.5% tolerance, 700 µA cathode current, and full -40°C to 125°C operating temperature range. The part is in active production status with 12,700 units in stock. ROHS3 compliance and REACH unaffected status are maintained. This substitution requires no circuit redesign.

Secondary Recommendations: Diodes Incorporated AS431 Series

The AS431AZTR-E1 and AS431AZTR-G1 variants provide ±0.5% tolerance matching the original specification with 2.5V minimum output voltage. Both maintain 100 mA output current and -40°C to 125°C operating range. The 0.005V difference in minimum output voltage (2.495V vs 2.5V) is within typical application tolerances for adjustable reference circuits. These parts offer high inventory availability (117,200 and 150,200 units respectively) and active production status.

Alternative for Relaxed Tolerance Applications: AZ431 Series

The AZ431AZ-ATRE1 and AZ431AZ-ATRG1 provide ±0.4% tolerance, exceeding the original ±0.5% specification. These parts are suitable for applications where tighter tolerance is beneficial. Inventory availability is substantial (1,300,100 and 1,410 units respectively).

Temperature-Constrained Applications: KA431AZTA

The KA431AZTA from onsemi maintains the 2.495V output voltage and TO-92-3 package of the original part. However, the operating temperature range is limited to -25°C to 85°C, making this option suitable only for commercial temperature applications. The ±1% tolerance is relaxed compared to the original specification.

All recommended substitutes are ROHS3 compliant and REACH unaffected, maintaining regulatory compliance with the original part.

Frequently Asked Questions (FAQ)

Q: Can I use AS431 parts as direct replacements for the TL431BQLPME3?

A: Yes, with circuit verification. The AS431 series maintains the same shunt reference topology, adjustable output type, 100 mA output current, and ±0.5% tolerance (AS431AZTR variants). The primary difference is the minimum output voltage specification of 2.5V versus 2.495V. For most adjustable reference applications, this 0.005V difference is negligible. Verify your specific circuit's voltage divider network to confirm compatibility.

Q: What is the difference between TO-92 and TO-92-3 packaging?

A: Both designations refer to the same three-lead through-hole package with formed leads (TO-226-3 or TO-226AA). The packaging is mechanically and electrically identical. Parts specified as TO-92 or TO-92-3 are interchangeable in PCB layouts designed for this package type.

Q: Why do some substitute parts have different cathode current specifications?

A: Cathode current (minimum operating current) varies by manufacturer design. The TL431BQLPME3 specifies 700 µA, while most Diodes Incorporated alternatives specify 1 mA. The AS431IAZTR-G1 specifies 50 µA. These differences affect the minimum load resistance required for stable operation. Verify your circuit's bias network can supply the required cathode current for your selected substitute.

Q: Is the KA431AZTA suitable for industrial temperature applications?

A: No. The KA431AZTA operates from -25°C to 85°C, which does not cover the full industrial range of -40°C to 125°C specified for the TL431BQLPME3. Use this part only in commercial temperature applications (-0°C to 70°C) or where your specific application operates within the -25°C to 85°C range.

Q: What tolerance specification should I select for my application?

A: The original TL431BQLPME3 specifies ±0.5% tolerance. For direct replacement, select substitute parts with ±0.5% or tighter tolerance (such as AZ431 series at ±0.4%). Parts with ±1% tolerance (AS431BZTR or KA431AZTA) are acceptable only if your circuit design accommodates the relaxed tolerance specification.

Q: Are all recommended substitutes ROHS3 compliant?

A: Yes. All substitute parts listed maintain ROHS3 compliance and REACH unaffected status, matching the regulatory compliance of the original TL431BQLPME3.

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