TL431ACDG4 Equivalent & Substitute Parts

Part Overview

The TL431ACDG4 is a shunt voltage reference IC manufactured by Texas Instruments, classified as a Power Management (PMIC) component. This adjustable reference device operates across a 2.495V to 36V output range with ±1% tolerance and supports 100 mA output current in an 8-SOIC surface mount package. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Manufacturer Part Number	TL431ACDG4
Manufacturer	Texas Instruments
Reference Type	Shunt
Output Type	Adjustable
Voltage - Output (Min/Fixed)	2.495V
Voltage - Output (Max)	36V
Current - Output	100 mA
Tolerance	±1%
Current - Cathode	600 µA
Operating Temperature	0°C ~ 70°C (TA)
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 for the TL431ACDG4 is determined by the following critical parameters:

Electrical Compatibility Requirements:

Reference Type: Shunt (fixed requirement)
Output Type: Adjustable (fixed requirement)
Voltage - Output (Min/Fixed): 2.495V or compatible minimum
Voltage - Output (Max): 36V or higher
Current - Output: 100 mA (fixed requirement)
Tolerance: ±1% or better (tighter tolerance acceptable)
Operating Temperature: 0°C ~ 70°C minimum range

Mechanical Compatibility Requirements:

Package / Case: 8-SOIC (0.154", 3.90mm Width) - fixed requirement
Mounting Type: Surface Mount (fixed requirement)

Compliance Requirements:

RoHS3 Compliant (preferred)

Substitute parts are grouped into two categories:

Direct Equivalents (Identical Electrical & Mechanical Specifications): Parts that match all critical parameters including voltage range, tolerance, cathode current, and temperature range.

Functional Equivalents (Compatible Electrical Performance with Minor Parameter Variations): Parts that maintain core functionality within acceptable engineering tolerances, including higher voltage maximums, improved tolerance specifications, or extended temperature ranges. These parts are electrically compatible but may have different cathode current specifications or operating temperature ranges.

Parameter Comparison

Part Number	Manufacturer	Voltage Min (V)	Voltage Max (V)	Current Output (mA)	Tolerance	Cathode Current	Temp Range (°C)	Package	Status
TL431ACDG4	Texas Instruments	2.495	36	100	±1%	600 µA	0 ~ 70	8-SOIC	Obsolete
TL431ACD	STMicroelectronics	2.495	36	100	±1%	600 µA	0 ~ 70	8-SOIC	Obsolete
LM431ACM/NOPB	National Semiconductor	2.495	37	100	±2.2%	1 mA	0 ~ 70	8-SOIC	Active
LM431ACMX/NOPB	Texas Instruments	2.495	37	100	±2.2%	1 mA	0 ~ 70	8-SOIC	Active
LM431BCM/NOPB	Texas Instruments	2.495	37	100	±1%	1 mA	0 ~ 70	8-SOIC	Active
LM431BCMX/NOPB	National Semiconductor	2.495	37	100	±1%	1 mA	0 ~ 70	8-SOIC	Active
LM431BCMX	National Semiconductor	2.495	36	100	±1%	1 mA	-25 ~ 85	8-SOIC	Active
TL431AIDT	STMicroelectronics	2.495	36	100	±1%	700 µA	-40 ~ 105	8-SOIC	Active
KA431DTF	onsemi	2.5	36	100	±2%	1 mA	-25 ~ 85	8-SOIC	Active
LT1431CS8#PBF	Analog Devices Inc.	2.5	36	100	±0.4%	1 mA	0 ~ 70	8-SOIC	Active
LT1431CS8#TRPBF	Analog Devices Inc.	2.5	36	100	±0.4%	1 mA	0 ~ 70	8-SOIC	Active

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications):

TL431ACD (STMicroelectronics) provides the closest electrical and mechanical match to the TL431ACDG4. Both devices share identical voltage ranges (2.495V to 36V), ±1% tolerance, 100 mA output current, and 8-SOIC packaging. However, TL431ACD is also listed as obsolete, limiting long-term availability.

For Active Production Alternatives:

LM431BCM/NOPB and LM431BCMX/NOPB (both ±1% tolerance) maintain the critical ±1% tolerance specification of the original part while offering active product status. These parts operate within the same 0°C to 70°C temperature range and support 100 mA output current in 8-SOIC packaging. The maximum output voltage increases to 37V, which is compatible with applications designed for 36V operation. Cathode current increases to 1 mA, which may require circuit design verification in current-sensitive applications.

LM431BCMX (National Semiconductor) extends the operating temperature range to -25°C to 85°C while maintaining ±1% tolerance and 36V maximum output voltage, making it suitable for applications requiring wider temperature operation.

For Enhanced Performance:

LT1431CS8#PBF and LT1431CS8#TRPBF (Analog Devices Inc.) offer superior ±0.4% tolerance, improving output voltage accuracy. These parts maintain 36V maximum output and 100 mA current capacity in 8-SOIC packaging. The minimum output voltage is 2.5V (versus 2.495V), which is functionally equivalent for most applications.

TL431AIDT (STMicroelectronics) provides an active alternative with extended temperature range (-40°C to 105°C) and maintains ±1% tolerance with 36V maximum output. This part is suitable for applications requiring industrial or automotive temperature specifications.

For Cost-Optimized Selection:

LM431ACM/NOPB and LM431ACMX/NOPB offer active status with relaxed ±2.2% tolerance. These parts are suitable for applications where tighter tolerance is not critical. Maximum output voltage increases to 37V, and cathode current is 1 mA.

KA431DTF (onsemi) provides ±2% tolerance with extended temperature range (-25°C to 85°C) and active product status. Minimum output voltage is 2.5V, which is compatible with standard applications.

All recommended substitutes maintain RoHS3 compliance and 8-SOIC surface mount packaging, ensuring PCB compatibility without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can I use LM431BCM/NOPB as a direct replacement for TL431ACDG4?

A: LM431BCM/NOPB is electrically compatible for most applications. Both parts maintain ±1% tolerance, 100 mA output current, and 8-SOIC packaging. The maximum output voltage increases from 36V to 37V, which is acceptable for designs operating at or below 36V. Cathode current increases from 600 µA to 1 mA; verify this does not impact bias current requirements in your circuit. Both operate within the 0°C to 70°C temperature range.

Q: What is the difference between TL431 and LM431 series parts?

A: Both TL431 and LM431 are shunt voltage reference ICs with similar core functionality. The primary differences are manufacturer (Texas Instruments vs. National Semiconductor/Analog Devices) and minor parameter variations such as cathode current and temperature coefficient. Electrical performance is equivalent when tolerance and voltage specifications match.

Q: Why do some substitutes have higher maximum output voltage (37V vs. 36V)?

A: Higher maximum voltage ratings provide additional design margin and are backward compatible with applications designed for 36V operation. The actual output voltage is set by external resistor networks and is not affected by the device's maximum rating.

Q: Can I use LT1431CS8#PBF if my application requires ±1% tolerance but the part offers ±0.4%?

A: Yes. Tighter tolerance specifications are always acceptable as substitutes. The ±0.4% tolerance of LT1431CS8#PBF exceeds the ±1% requirement of the original part, providing improved output voltage accuracy.

Q: Are all substitute parts RoHS3 compliant?

A: All recommended substitute parts listed in this document are RoHS3 compliant, ensuring compatibility with environmental and regulatory requirements.

Q: Does the 8-SOIC package differ between manufacturers?

A: The 8-SOIC package (0.154", 3.90mm Width) is standardized across all recommended substitutes. All parts are pin-compatible and can be used as direct PCB replacements without layout modifications.

Q: Which substitute offers the widest operating temperature range?

A: TL431AIDT (STMicroelectronics) provides the widest operating temperature range of -40°C to 105°C, making it suitable for industrial and automotive applications. This part maintains ±1% tolerance and 36V maximum output voltage.

Q: Can I mix different substitute parts in the same design?

A: Yes, provided all parts meet the electrical requirements of your circuit. However, for production consistency and supply chain management, selecting a single qualified substitute is recommended.

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