MC7809AECT Equivalent & Substitute Parts

Part Overview

The MC7809AECT is a linear voltage regulator IC manufactured by onsemi, designed to provide a fixed positive 9V output at 1A current capacity in a TO-220-3 through-hole package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and component sourcing.

The MC7809AECT operates across an input voltage range up to 35V with a maximum dropout voltage of 2V at 1A, incorporating over-temperature and short-circuit protection. Its primary application is in power management circuits requiring regulated 9V output with moderate current demands.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	9V
Output Current	1A
Input Voltage (Max)	35V
Dropout Voltage (Max)	2V @ 1A (Typ)
Quiescent Current	6 mA
PSRR	62dB (120Hz)
Package / Case	TO-220-3
Operating Temperature	0°C ~ 125°C
Protection Features	Over Temperature, Short Circuit

Substitute Part Grouping Explanation

Substitution for the MC7809AECT is determined by the following critical parameters:

Fixed output voltage of 9V
Output current capability (1A minimum for direct replacement)
Maximum input voltage of 35V
TO-220-3 package compatibility
Through-hole mounting type
Protection features (over-temperature and short-circuit minimum)

Substitute parts are grouped into three categories:

Parametric Equivalents (1A Output): Parts with identical 1A output current, 9V fixed output, and equivalent electrical characteristics. These provide direct functional replacement.

Similar Parts (Higher Current Output): Parts with 1.5A or 2A output capability. These can substitute when higher current capacity is acceptable or beneficial, as they maintain the same voltage regulation and package form factor.

Similar Parts (Lower Current Output): Parts with 500mA output capability. These substitute only when circuit current requirements do not exceed 500mA.

Parameter Comparison

Part Number	Manufacturer	Output Current	Dropout Voltage	Quiescent Current	PSRR (120Hz)	Operating Temp	Product Status
MC7809AECT	onsemi	1A	2V @ 1A (Typ)	6 mA	62dB	0°C ~ 125°C	Obsolete
MC7809ACTG	onsemi	1A	2V @ 1A (Typ)	6 mA	61dB	0°C ~ 125°C	Obsolete
MC7809CTG	onsemi	1A	2V @ 1A (Typ)	8 mA	61dB	0°C ~ 125°C	Active
MC7809BTG	onsemi	1A	2V @ 1A (Typ)	8 mA	61dB	-40°C ~ 125°C	Obsolete
MC78M09CTG	onsemi	500mA	—	—	80dB	0°C ~ 125°C	Obsolete
L7809ABV-DG	STMicroelectronics	1.5A	2V @ 1A (Typ)	6 mA	61dB	-40°C ~ 125°C	Obsolete
L7809CV	STMicroelectronics	1.5A	2V @ 1A (Typ)	8 mA	55dB	0°C ~ 125°C	Obsolete
L78M09CV	STMicroelectronics	500mA	—	6 mA	56dB	0°C ~ 125°C	Obsolete
L78S09CV	STMicroelectronics	2A	—	8 mA	47dB	0°C ~ 150°C	Obsolete

Engineering Selection Recommendations

Primary Recommendation: MC7809CTG (onsemi) is the preferred substitute. It maintains identical electrical specifications to the MC7809AECT with 1A output current, 9V fixed output, and TO-220-3 package compatibility. Critically, MC7809CTG holds Active product status, ensuring long-term availability and supply chain stability. It carries RoHS3 compliance certification.

Extended Temperature Range Alternative: MC7809BTG (onsemi) provides the same 1A output current and electrical characteristics as the MC7809AECT but extends the operating temperature range to -40°C ~ 125°C. This part is suitable for applications requiring enhanced low-temperature performance. Product status is Obsolete.

Higher Current Capacity Alternatives: L7809ABV-DG and L7809CV (STMicroelectronics) both provide 1.5A output current while maintaining 9V fixed output and TO-220-3 package compatibility. These parts accommodate circuits requiring current capacity beyond 1A. Both carry RoHS3 compliance. L7809ABV-DG extends operating temperature to -40°C ~ 125°C.

Lower Current Alternatives: MC78M09CTG (onsemi) and L78M09CV (STMicroelectronics) both provide 500mA output current. These substitute only when circuit design confirms maximum current draw does not exceed 500mA.

High Current Alternative: L78S09CV (STMicroelectronics) provides 2A output current with extended operating temperature to 0°C ~ 150°C. This part accommodates high-current applications while maintaining 9V output and TO-220-3 package form factor.

Frequently Asked Questions (FAQ)

Q: Can MC7809CTG directly replace MC7809AECT?

A: Yes. MC7809CTG provides identical electrical performance with 1A output current, 9V fixed output, 2V dropout voltage at 1A, and TO-220-3 package compatibility. The primary advantage is Active product status, ensuring continued availability.

Q: What is the difference between MC7809AECT and MC7809ACTG?

A: Both parts deliver 1A output current and 9V fixed output with equivalent electrical characteristics. MC7809ACTG has slightly lower PSRR (61dB vs 62dB) and identical quiescent current (6 mA). Both are Obsolete. MC7809CTG is the recommended active alternative.

Q: Can I use L7809CV instead of MC7809AECT?

A: Yes, with considerations. L7809CV provides higher output current (1.5A vs 1A) and maintains 9V output with TO-220-3 package compatibility. However, quiescent current is slightly higher (8 mA vs 6 mA) and PSRR is lower (55dB vs 62dB). This part is suitable when higher current capacity is acceptable.

Q: What is the difference between MC78M09CTG and MC7809AECT?

A: MC78M09CTG provides 500mA output current compared to MC7809AECT's 1A. Both maintain 9V output and TO-220-3 package compatibility. MC78M09CTG substitutes only when circuit current requirements do not exceed 500mA. PSRR is higher (80dB vs 62dB).

Q: Are all substitute parts RoHS3 compliant?

A: All substitute parts listed carry RoHS3 compliance certification, meeting environmental and regulatory requirements equivalent to the original MC7809AECT.

Q: Which substitute offers the widest operating temperature range?

A: L78S09CV provides the widest operating temperature range (0°C ~ 150°C) compared to MC7809AECT (0°C ~ 125°C). However, it delivers 2A output current, making it suitable only for applications requiring higher current capacity.

Q: Can I use a higher current-rated part in place of MC7809AECT?

A: Yes. Parts with higher current ratings (L7809ABV-DG at 1.5A, L7809CV at 1.5A, or L78S09CV at 2A) provide backward compatibility. The circuit will operate within the original 1A current specification while benefiting from additional current headroom.

Q: What is the package compatibility for all substitute parts?

A: All substitute parts use TO-220-3 package with through-hole mounting, ensuring mechanical and electrical compatibility with MC7809AECT PCB layouts.

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