MC7809ECT Equivalent & Substitute Parts

Part Overview

The MC7809ECT 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 device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The MC7809ECT serves applications requiring stable 9V regulation from input sources up to 35V, with integrated over-temperature and short-circuit protection.

Key Parameters

Parameter	Value
Manufacturer Part Number	MC7809ECT
Manufacturer	onsemi
Output Voltage (Fixed)	9V
Output Current	1A
Input Voltage (Max)	35V
Voltage Dropout (Max)	2V @ 1A (Typ)
Quiescent Current	8 mA
PSRR	71dB (120Hz)
Package / Case	TO-220-3
Mounting Type	Through Hole
Operating Temperature	0°C ~ 125°C
Protection Features	Over Temperature, Short Circuit
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the MC7809ECT is determined by the following critical parameters:

Output voltage: 9V fixed
Output current capability: minimum 1A
Package type: TO-220-3 through-hole
Input voltage rating: 35V maximum
Protection features: Over-temperature and short-circuit protection
Mounting compatibility: Through-hole configuration

Substitute parts are grouped into two categories:

Parametric Equivalents (1A Output Current): Parts with identical 1A output current rating, matching the MC7809ECT's primary load-handling capability. These include MC7809ACTG and MC7809CTG from onsemi, as well as L7809ABV-DG from STMicroelectronics.

Higher Current Alternatives (500mA to 2A Output): Parts with different output current ratings that maintain the same 9V output voltage and TO-220-3 package. These include MC78M09CTG (500mA), L7809CV (1.5A), L78M09CV (500mA), L78S09CV (2A), and MC7809BTG (1A).

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Voltage Dropout (Max)	Quiescent Current	PSRR (120Hz)	Package	Operating Temp	Product Status
MC7809ECT	onsemi	9V	1A	35V	2V @ 1A	8 mA	71dB	TO-220-3	0°C ~ 125°C	Obsolete
MC7809ACTG	onsemi	9V	1A	35V	2V @ 1A	6 mA	61dB	TO-220-3	0°C ~ 125°C	Obsolete
MC7809CTG	onsemi	9V	1A	35V	2V @ 1A	8 mA	61dB	TO-220-3	0°C ~ 125°C	Active
MC78M09CTG	onsemi	9V	500mA	35V	—	8 mA	80dB	TO-220-3	0°C ~ 125°C	Obsolete
L7809ABV-DG	STMicroelectronics	9V	1.5A	35V	2V @ 1A	6 mA	61dB	TO-220-3	-40°C ~ 125°C	Obsolete
L7809CV	STMicroelectronics	9V	1.5A	35V	2V @ 1A	8 mA	55dB	TO-220-3	0°C ~ 125°C	Obsolete
L78M09CV	STMicroelectronics	9V	500mA	35V	—	6 mA	56dB	TO-220-3	0°C ~ 125°C	Obsolete
L78S09CV	STMicroelectronics	9V	2A	35V	—	8 mA	47dB	TO-220-3	0°C ~ 150°C	Obsolete
MC7809BTG	onsemi	9V	1A	35V	2V @ 1A	8 mA	61dB	TO-220-3	-40°C ~ 125°C	Obsolete

Engineering Selection Recommendations

Primary Recommendation: MC7809CTG is the preferred substitute. This part maintains identical electrical specifications to the MC7809ECT (1A output, 9V fixed, TO-220-3 package) and is the only substitute listed with Active product status, ensuring long-term availability and manufacturing support.

Secondary Recommendations for Equivalent Performance:

MC7809ACTG provides parametric equivalence with 1A output current and identical voltage dropout characteristics. This part is RoHS3 compliant and suitable for applications requiring the same load capacity as the original MC7809ECT.

MC7809BTG offers 1A output current with extended operating temperature range (-40°C to 125°C), providing thermal margin for applications operating below 0°C. This part is RoHS3 compliant.

Alternative Recommendations for Higher Current Applications:

L7809ABV-DG and L7809CV from STMicroelectronics provide 1.5A output current, offering increased headroom for designs approaching the 1A limit. Both maintain the same 9V output and TO-220-3 package. L7809ABV-DG extends the operating temperature range to -40°C.

L78S09CV provides 2A output current for applications requiring significant current margin. Operating temperature extends to 150°C, suitable for high-temperature environments.

For Current-Limited Applications:

MC78M09CTG and L78M09CV are 500mA variants suitable only for applications with reduced current requirements. These parts should not be used as direct replacements for 1A-rated designs.

Frequently Asked Questions (FAQ)

Q: Can MC7809CTG directly replace MC7809ECT?

A: Yes. MC7809CTG is a direct parametric equivalent with identical 1A output current, 9V fixed output voltage, and TO-220-3 package. The primary advantage is Active product status, ensuring continued availability. Both parts share the same voltage dropout specification (2V @ 1A typical) and protection features.

Q: What is the difference between MC7809ACTG and MC7809CTG?

A: Both are 1A regulators with 9V output in TO-220-3 packages. MC7809ACTG has lower quiescent current (6 mA vs. 8 mA) and higher PSRR (61dB vs. 61dB). MC7809CTG is currently in Active production status. For new designs, MC7809CTG is preferred due to availability.

Q: Can I use L7809CV (1.5A) instead of MC7809ECT (1A)?

A: Yes, with design considerations. L7809CV provides higher current capacity (1.5A vs. 1A), making it suitable for applications approaching the 1A limit. Both maintain 9V output and TO-220-3 package compatibility. L7809CV has lower PSRR (55dB vs. 71dB), which may affect noise-sensitive applications. Operating temperature range is identical (0°C to 125°C).

Q: What is the difference between L78M09CV (500mA) and MC7809ECT (1A)?

A: L78M09CV is rated for 500mA output current, half the capacity of MC7809ECT. This part is suitable only for applications with reduced current requirements. Do not use as a direct replacement for 1A designs without verifying load current specifications.

Q: Are all substitute parts RoHS3 compliant?

A: All listed substitute parts are RoHS3 compliant except MC7809ECT (original part, status not specified). MC7809CTG, MC7809ACTG, MC7809BTG, and all STMicroelectronics variants (L7809ABV-DG, L7809CV, L78M09CV, L78S09CV) are confirmed RoHS3 compliant.

Q: Which substitute has the best PSRR performance?

A: MC78M09CTG has the highest PSRR at 80dB (120Hz). However, this is a 500mA part and not suitable for 1A applications. Among 1A-rated equivalents, MC7809ECT has the highest PSRR at 71dB. MC7809ACTG and MC7809CTG both provide 61dB PSRR.

Q: Can I use MC7809BTG for applications below 0°C?

A: Yes. MC7809BTG extends the operating temperature range to -40°C, compared to 0°C minimum for MC7809ECT. This part is suitable for cold-environment applications while maintaining 1A output current and identical electrical specifications.

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

A: Yes. All listed substitute parts use TO-220-3 through-hole packages, ensuring mechanical and thermal compatibility with MC7809ECT designs. No PCB layout modifications are required for package substitution.

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