MC7812AECT Linear Voltage Regulator - Equivalent & Substitute Parts

Part Overview

The MC7812AECT is a linear voltage regulator IC manufactured by onsemi, delivering a fixed positive 12V output at 1A current capacity in a TO-220-3 through-hole package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The MC7812AECT provides over-temperature and short-circuit protection with a maximum input voltage of 35V and typical dropout voltage of 2V at 1A load.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	12V
Output Current	1A
Input Voltage (Max)	35V
Dropout Voltage (Typ)	2V @ 1A
Quiescent Current	6 mA
PSRR	60dB (120Hz)
Operating Temperature	0°C ~ 125°C
Package	TO-220-3
Protection Features	Over Temperature, Short Circuit

Substitute Part Grouping Explanation

Substitution for the MC7812AECT is determined by the following critical parameters: fixed 12V output voltage, output current capacity, maximum input voltage rating, package type (TO-220-3), and protection features. Parts are grouped into two categories:

Parametric Equivalents maintain identical electrical specifications including 1A output current, 2V dropout voltage at 1A, 6 mA quiescent current, and 60dB PSRR. These parts are direct functional replacements with active product status.

Similar Substitutes provide the same 12V fixed output and TO-220-3 package but may differ in output current capacity (500mA variants), quiescent current specifications, or PSRR frequency rating. These are suitable when the application does not require the full 1A output current or when extended temperature ranges are beneficial.

Cross-Manufacturer Alternatives from Diodes Incorporated and STMicroelectronics maintain core electrical parameters while offering different product status and compliance certifications.

Parameter Comparison

Part Number	Manufacturer	Output Current	Input Voltage (Max)	Dropout Voltage	Quiescent Current	PSRR	Operating Temp	Product Status	Package
MC7812AECT	onsemi	1A	35V	2V @ 1A	6 mA	60dB (120Hz)	0°C ~ 125°C	Obsolete	TO-220-3
MC7812ACTG	onsemi	1A	35V	2V @ 1A	6 mA	60dB (1kHz)	0°C ~ 125°C	Active	TO-220-3
MC7812CTG	onsemi	1A	35V	2V @ 1A	6.5 mA	60dB (1kHz)	0°C ~ 125°C	Active	TO-220-3
MC7812BTG	onsemi	1A	35V	2V @ 1A	8 mA	60dB (1kHz)	-40°C ~ 125°C	Active	TO-220-3
AS7812AT-E1	Diodes Incorporated	1A	32V	2V @ 1A	6 mA	60dB (120Hz)	-40°C ~ 125°C	Active	TO-220-3
L7812ABV	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	60dB (120Hz)	-40°C ~ 125°C	Active	TO-220-3
L7812ACV	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	60dB (120Hz)	0°C ~ 125°C	Active	TO-220-3
L7812CV	UMW	1.2A	35V	—	6 mA	—	-40°C ~ 105°C	Active	TO-220-3
MC78M12ACTG	onsemi	500mA	35V	—	—	80dB (120Hz)	0°C ~ 125°C	Obsolete	TO-220-3
MC78M12BTG	onsemi	500mA	35V	—	—	80dB (120Hz)	-40°C ~ 125°C	Active	TO-220-3
MC78M12CTG	onsemi	500mA	35V	—	—	80dB (120Hz)	0°C ~ 125°C	Active	TO-220-3

Engineering Selection Recommendations

Primary Recommendation for Direct Replacement: MC7812ACTG (onsemi) is the preferred parametric equivalent. It maintains identical electrical specifications to the MC7812AECT with active product status, RoHS3 compliance, and high inventory availability (4403 pcs). The PSRR specification is measured at 1kHz rather than 120Hz, representing improved performance characteristics.

Alternative with Extended Temperature Range: MC7812BTG (onsemi) provides the same 1A output current and electrical performance with extended operating temperature range (-40°C to 125°C) and active product status. Quiescent current is slightly elevated at 8 mA compared to the original 6 mA specification.

Cross-Manufacturer Options: AS7812AT-E1 (Diodes Incorporated) and L7812ABV/L7812ACV (STMicroelectronics) are functionally equivalent with active product status and RoHS3 compliance. L7812ABV and L7812ACV offer higher output current capacity (1.5A) with identical dropout voltage and quiescent current specifications. AS7812AT-E1 has a slightly lower maximum input voltage (32V vs 35V) but maintains all other critical parameters.

Lower Current Alternative: MC78M12CTG (onsemi) is suitable for applications requiring only 500mA output current. It provides superior PSRR (80dB at 120Hz) and active product status with identical 12V output and TO-220-3 package.

Frequently Asked Questions (FAQ)

Q: Can MC7812ACTG directly replace MC7812AECT without circuit modification? A: Yes. MC7812ACTG maintains identical output voltage (12V), output current (1A), input voltage rating (35V), dropout voltage (2V @ 1A), and quiescent current (6 mA). The TO-220-3 package pinout is identical. No circuit modifications are required.

Q: What is the difference between MC7812AECT and MC7812BTG? A: Both deliver 1A at 12V with identical electrical performance. MC7812BTG has an extended operating temperature range (-40°C to 125°C vs 0°C to 125°C) and slightly higher quiescent current (8 mA vs 6 mA). MC7812BTG has active product status while MC7812AECT is obsolete.

Q: Can L7812ABV be used as a substitute despite higher output current rating? A: Yes. L7812ABV is rated for 1.5A output current, which exceeds the 1A requirement of the MC7812AECT. Higher current capacity does not prevent substitution in applications requiring 1A or less. The device will operate within its safe operating area. All other electrical parameters match the original specification.

Q: Why would I choose MC78M12CTG over MC7812ACTG? A: MC78M12CTG is appropriate only if your application requires 500mA or less output current. It offers superior PSRR (80dB vs 60dB) but reduced current capacity. For applications requiring the full 1A output, MC7812ACTG is the correct choice.

Q: Are all substitute parts RoHS3 compliant? A: All active product status parts listed (MC7812ACTG, MC7812CTG, MC7812BTG, AS7812AT-E1, L7812ABV, L7812ACV, L7812CV) are RoHS3 compliant. The obsolete MC7812AECT and MC78M12ACTG do not have RoHS3 compliance specified.

Q: What is the significance of PSRR frequency difference (120Hz vs 1kHz)? A: PSRR (Power Supply Rejection Ratio) is frequency-dependent. MC7812AECT specifies 60dB at 120Hz, while MC7812ACTG specifies 60dB at 1kHz. Both maintain the same 60dB rejection ratio at their respective measurement frequencies. The higher frequency measurement in MC7812ACTG indicates performance across a broader frequency spectrum.

Q: Can I use AS7812AT-E1 if my input voltage reaches 35V? A: AS7812AT-E1 has a maximum input voltage rating of 32V, which is 3V lower than the MC7812AECT specification of 35V. Use AS7812AT-E1 only if your maximum input voltage does not exceed 32V. For applications requiring the full 35V input rating, use MC7812ACTG or other alternatives rated for 35V.

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