KA431D Equivalent & Substitute Parts

Part Overview

The KA431D is a shunt voltage reference IC manufactured by onsemi, designed for adjustable voltage regulation applications. This component provides a 2.5V to 36V adjustable output with ±2% tolerance and 100 mA output current capability in an 8-SOIC surface mount package. The KA431D is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across output voltage range, current capacity, tolerance specifications, and package form factor.

Key Parameters

Parameter	Value
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)
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the KA431D is determined by the following critical parameters:

Reference Type & Output Type: Must be shunt voltage reference with adjustable output
Output Voltage Range: Minimum 2.5V, maximum 36V
Output Current: 100 mA capability
Package: 8-SOIC form factor with 0.154" width (3.90mm)
Mounting: Surface mount technology
Tolerance: ±2% or better (tighter tolerance is acceptable)
Temperature Coefficient: 50ppm/°C typical
Cathode Current: 1 mA minimum

Substitute parts are grouped into two categories: direct equivalents (matching all electrical specifications and product status) and compatible alternatives (meeting electrical requirements with enhanced specifications or different product status).

Parameter Comparison

Part Number	Manufacturer	Product Status	Output Min/Fixed	Output Max	Current Output	Tolerance	Temp Coeff	Operating Temp	Package
KA431D	onsemi	Obsolete	2.5V	36V	100 mA	±2%	50ppm/°C	-25°C ~ 85°C	8-SOIC
LM431ACMX	National Semiconductor	Active	2.5V	36V	100 mA	±2%	50ppm/°C	-25°C ~ 85°C	8-SOIC
NCV431AIDR2G	onsemi	Active	2.495V	36V	100 mA	±1%	50ppm/°C	-40°C ~ 125°C	8-SOIC
TL431ACDG	onsemi	Active	2.495V	36V	100 mA	±1%	50ppm/°C	0°C ~ 70°C	8-SOIC
TL431ACDR2G	onsemi	Active	2.495V	36V	100 mA	±1%	50ppm/°C	0°C ~ 70°C	8-SOIC
TL431AIDG	onsemi	Active	2.495V	36V	100 mA	±1%	50ppm/°C	-40°C ~ 85°C	8-SOIC
TL431AIDR2G	onsemi	Active	2.495V	36V	100 mA	±1%	50ppm/°C	-40°C ~ 85°C	8-SOIC
TL431BCDR2G	onsemi	Active	2.495V	36V	100 mA	±0.4%	50ppm/°C	0°C ~ 70°C	8-SOIC
TL431BIDG	onsemi	Active	2.495V	36V	100 mA	±0.4%	50ppm/°C	-40°C ~ 85°C	8-SOIC
TL431BIDR2G	onsemi	Active	2.495V	36V	100 mA	±0.4%	50ppm/°C	-40°C ~ 85°C	8-SOIC
TL431BVDR2G	onsemi	Active	2.495V	36V	100 mA	±0.4%	50ppm/°C	-40°C ~ 125°C	8-SOIC

Engineering Selection Recommendations

Direct Equivalent (Recommended Primary Substitute)

LM431ACMX is the primary substitute for KA431D. This part is manufactured by National Semiconductor and maintains active product status. It matches all electrical specifications including ±2% tolerance, 2.5V to 36V output range, 100 mA output current, and identical operating temperature range (-25°C ~ 85°C). The 8-SOIC package is identical. This part provides direct functional replacement without design modification.

Compatible Alternatives with Enhanced Specifications

The TL431 series (TL431AIDG, TL431AIDR2G, TL431ACDG, TL431ACDR2G) and NCV431AIDR2G offer tighter tolerance (±1%) compared to the KA431D (±2%), making them suitable for applications requiring improved accuracy. These parts maintain the same output voltage range, current capacity, and package form factor. Operating temperature ranges vary by grade; select based on application requirements.

High-Precision Alternatives

TL431B series (TL431BCDR2G, TL431BIDG, TL431BIDR2G, TL431BVDR2G) provide ±0.4% tolerance for precision voltage reference applications. TL431BVDR2G extends the operating temperature to -40°C ~ 125°C, suitable for automotive and extended-temperature applications. All maintain 100 mA output current and 8-SOIC packaging.

Selection Criteria

For direct replacement in existing designs: use LM431ACMX
For improved accuracy requirements: use TL431A series (±1% tolerance)
For precision applications: use TL431B series (±0.4% tolerance)
For automotive/extended temperature: use NCV431AIDR2G or TL431BVDR2G
All substitutes are RoHS3 compliant and REACH unaffected

Frequently Asked Questions (FAQ)

Q: Can I use TL431AIDR2G as a direct replacement for KA431D?

A: Yes. TL431AIDR2G is electrically compatible with KA431D. Both provide 2.5V to 36V adjustable output, 100 mA current, and operate in the 8-SOIC package. TL431AIDR2G offers tighter tolerance (±1% vs ±2%) and extended temperature range (-40°C ~ 85°C), making it suitable for the same applications with improved performance.

Q: What is the difference between TL431A and TL431B series?

A: The primary difference is tolerance specification. TL431A series maintains ±1% tolerance, while TL431B series provides ±0.4% tolerance. Both series share identical output voltage range (2.495V to 36V), output current (100 mA), temperature coefficient (50ppm/°C), and 8-SOIC package. Select TL431B for applications requiring higher accuracy.

Q: Are all substitute parts available in the same packaging options?

A: Substitute parts are available in different packaging formats (Tube, Tape & Reel, Cut Tape). The 8-SOIC component package is identical across all parts. Packaging format (Tube, TR, CT) affects handling and storage but does not impact electrical performance or PCB compatibility.

Q: Can I use NCV431AIDR2G in a commercial temperature application?

A: NCV431AIDR2G is qualified for automotive applications (AEC-Q100) with operating temperature -40°C ~ 125°C. It is suitable for commercial applications within this temperature range. For standard commercial temperature range (0°C ~ 70°C), TL431ACDG or TL431ACDR2G are appropriate alternatives.

Q: What is the minimum cathode current requirement?

A: All substitute parts require 1 mA minimum cathode current, matching the KA431D specification. This parameter must be maintained in circuit design to ensure proper voltage reference operation.

Q: Are all substitute parts RoHS compliant?

A: Yes. All listed substitute parts are RoHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

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