KA7912 Linear Voltage Regulator IC Equivalent & Substitute Parts

Part Overview

The KA7912 is a linear voltage regulator IC manufactured by onsemi, designed to provide a fixed negative 12V output at 1A current capacity in a TO-220-3 package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The KA7912 operates across an input voltage range up to -35V and includes over-temperature and short-circuit protection features suitable for power management applications requiring negative voltage regulation.

Key Parameters

Parameter	Value
Output Configuration	Negative
Output Type	Fixed
Voltage - Output (Min/Fixed)	-12V
Voltage - Input (Max)	-35V
Current - Output	1A
Voltage Dropout (Max)	2V @ 1A (Typ)
Operating Temperature	0°C ~ 125°C
Package / Case	TO-220-3
Mounting Type	Through Hole
Protection Features	Over Temperature, Short Circuit

Substitute Part Grouping Explanation

Substitute parts for the KA7912 are categorized based on strict electrical and mechanical compatibility criteria. The primary substitution parameters are:

Critical Parameters for Substitution:

Output voltage: -12V (fixed)
Output configuration: Negative
Package type: TO-220-3 (through-hole mounting)
Maximum input voltage: -35V
Protection features: Over-temperature and short-circuit protection

Substitution Categories:

Direct Equivalents (1A Output Current): Parts with identical 1A output current rating, matching dropout voltage specifications, and active product status. These include MC7912ACTG, MC7912BTG, MC7912CTG, and LM7912CT/NOPB.

Higher Current Capacity Substitutes (1.5A Output Current): Parts rated for 1.5A output current, which provide enhanced current delivery capability while maintaining -12V fixed output and TO-220-3 packaging. These include L7912ACV, L7912ACV-DG, L7912CV, and L7912CV-DG from STMicroelectronics, and LM7912CT/NOPB from Texas Instruments.

Reduced Current Capacity Substitute (500mA Output Current): MC79M12BTG rated for 500mA output current, suitable only for applications with lower current requirements than the original 1A specification.

Parametric Equivalent (Obsolete): LM7912CT from Fairchild Semiconductor matches the original KA7912 electrical specifications but carries obsolete product status.

Parameter Comparison

Part Number	Manufacturer	Product Status	Output Current	Voltage Dropout (Max)	Operating Temperature	Protection Features	RoHS Status
KA7912	onsemi	Obsolete	1A	2V @ 1A (Typ)	0°C ~ 125°C	Over Temperature, Short Circuit	Not specified
MC7912ACTG	onsemi	Active	1A	1.3V @ 1A (Typ)	0°C ~ 125°C	Over Current, Over Temperature	ROHS3 Compliant
MC7912BTG	onsemi	Active	1A	1.3V @ 1A (Typ)	-40°C ~ 125°C	Over Current, Over Temperature	ROHS3 Compliant
MC7912CTG	onsemi	Active	1A	1.3V @ 1A (Typ)	0°C ~ 125°C	Over Current, Over Temperature	ROHS3 Compliant
MC79M12BTG	onsemi	Active	500mA	1.1V @ 500mA (Typ)	-40°C ~ 125°C	Over Current, Over Temperature	ROHS3 Compliant
L7912ACV	STMicroelectronics	Active	1.5A	1.1V @ 1A (Typ)	0°C ~ 125°C	Over Temperature, Short Circuit	ROHS3 Compliant
L7912ACV-DG	STMicroelectronics	Obsolete	1.5A	1.1V @ 1A (Typ)	0°C ~ 125°C	Over Temperature, Short Circuit	ROHS3 Compliant
L7912CV	STMicroelectronics	Active	1.5A	1.1V @ 1A (Typ)	0°C ~ 125°C	Over Temperature, Short Circuit	ROHS3 Compliant
L7912CV-DG	STMicroelectronics	Active	1.5A	1.1V @ 1A (Typ)	0°C ~ 125°C	Over Temperature, Short Circuit	ROHS3 Compliant
LM7912CT/NOPB	Texas Instruments	Active	1.5A	1.1V @ 1A	0°C ~ 125°C	Over Temperature, Short Circuit	ROHS3 Compliant
LM7912CT	Fairchild Semiconductor	Obsolete	1A	2V @ 1A (Typ)	0°C ~ 125°C	Over Temperature, Short Circuit	RoHS non-compliant

Engineering Selection Recommendations

For Active Production Designs:

Select from onsemi MC7912 series (MC7912ACTG, MC7912BTG, MC7912CTG) or STMicroelectronics L7912 series (L7912CV, L7912CV-DG) for designs requiring active product status and ROHS3 compliance. MC7912BTG provides extended operating temperature range (-40°C to 125°C) compared to the original KA7912 specification (0°C to 125°C), suitable for industrial applications. L7912CV and L7912CV-DG offer higher output current capacity (1.5A) with improved dropout voltage characteristics (1.1V vs. 2V), providing design margin for applications approaching the 1A limit.

For Extended Temperature Range Applications:

MC7912BTG supports -40°C to 125°C operating range, exceeding the KA7912 specification and enabling deployment in wider environmental conditions.

For Current Margin Requirements:

L7912ACV, L7912CV, L7912CV-DG, and LM7912CT/NOPB provide 1.5A output current capacity, offering 50% additional current headroom over the original 1A specification while maintaining -12V fixed output and TO-220-3 packaging.

For Reduced Current Applications:

MC79M12BTG is suitable only for applications with maximum current requirements of 500mA, representing a downgrade from the original 1A specification.

Compliance Considerations:

All active substitute parts carry ROHS3 compliance certification. LM7912CT from Fairchild Semiconductor, while parametrically equivalent to KA7912, carries obsolete product status and RoHS non-compliance, limiting suitability for new designs.

Frequently Asked Questions (FAQ)

Q: Can MC7912ACTG directly replace KA7912 in existing designs?

A: MC7912ACTG is electrically compatible with KA7912, maintaining -12V fixed output, 1A current capacity, and TO-220-3 packaging. The lower dropout voltage (1.3V vs. 2V) and active product status make it a suitable direct replacement. Operating temperature range differs (0°C to 125°C for both), so thermal specifications must be verified for your application.

Q: What is the difference between MC7912BTG and MC7912ACTG?

A: Both parts provide 1A output current and -12V fixed output in TO-220-3 packaging. MC7912BTG extends the operating temperature range to -40°C to 125°C, compared to MC7912ACTG at 0°C to 125°C. Select MC7912BTG for applications requiring low-temperature operation below 0°C.

Q: Why would I choose L7912CV over MC7912BTG?

A: L7912CV provides 1.5A output current capacity versus 1A for MC7912BTG, offering 50% additional current margin. Both maintain -12V fixed output and TO-220-3 packaging. L7912CV is manufactured by STMicroelectronics and carries active product status with ROHS3 compliance. Selection depends on current requirements and preferred supplier.

Q: Is MC79M12BTG a suitable substitute for KA7912?

A: MC79M12BTG is not recommended as a direct substitute. While it maintains -12V fixed output and TO-220-3 packaging, the output current rating is reduced to 500mA, representing a 50% downgrade from the original 1A specification. Use only in applications with confirmed maximum current requirements below 500mA.

Q: Can I use LM7912CT as a replacement for KA7912?

A: LM7912CT from Fairchild Semiconductor is parametrically equivalent to KA7912, matching 1A output current, 2V dropout voltage, and operating temperature range. However, LM7912CT carries obsolete product status and RoHS non-compliance, making it unsuitable for new production designs. Use active alternatives such as MC7912BTG or L7912CV instead.

Q: What is the difference between L7912CV and L7912CV-DG?

A: Both parts are manufactured by STMicroelectronics and provide identical electrical specifications: -12V fixed output, 1.5A current capacity, 1.1V dropout voltage, and TO-220-3 packaging. Both carry active product status and ROHS3 compliance. The "-DG" suffix indicates a specific packaging or distribution variant. Verify availability and lead times with your supplier for the specific variant required.

Q: Are all substitute parts available in the same TO-220-3 package?

A: All listed substitute parts use TO-220-3 through-hole packaging, maintaining mechanical compatibility with KA7912 PCB layouts. Verify pin configuration and lead spacing with component datasheets before board-level substitution.

Q: Which substitute offers the best dropout voltage performance?

A: L7912ACV, L7912ACV-DG, L7912CV, L7912CV-DG, and LM7912CT/NOPB all provide 1.1V dropout voltage at 1A, compared to 2V for KA7912. This 45% reduction in dropout voltage improves power efficiency and reduces thermal dissipation in the regulator.

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