MC7808ECT Linear Voltage Regulator - Equivalent & Substitute Parts

Part Overview

The MC7808ECT is a linear voltage regulator IC manufactured by onsemi, designed to provide a fixed positive 8V 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, maintenance, and production continuity. The MC7808ECT serves applications requiring stable 8V regulation with thermal and short-circuit protection in industrial and consumer electronics.

Key Parameters

Parameter	Value
Manufacturer Part Number	MC7808ECT
Manufacturer	onsemi
Output Voltage (Fixed)	8V
Output Current	1A
Input Voltage (Max)	35V
Voltage Dropout (Max)	2V @ 1A (Typ)
Quiescent Current	8 mA
PSRR	73dB (120Hz)
Protection Features	Over Temperature, Short Circuit
Operating Temperature Range	0°C ~ 125°C
Package / Case	TO-220-3
Mounting Type	Through Hole
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the MC7808ECT is determined by the following critical parameters:

Primary Substitution Criteria:

Fixed output voltage of 8V
Output current rating of 1A or greater
Maximum input voltage of 35V or greater
TO-220-3 or compatible TO-220 package
Through-hole mounting configuration
Over temperature and short circuit protection

Substitution Categories:

Category 1: Parametric Equivalents (Identical Specifications) Parts meeting all primary criteria with matching output current (1A) and identical electrical performance characteristics.

Category 2: Higher Current Capability (1.5A Output) Parts with 1.5A output current rating provide direct substitution with enhanced current headroom. These are backward compatible for 1A applications.

Category 3: Lower Current Capability (500mA Output) Parts with 500mA output current are suitable only for applications requiring less than 500mA and should not be used as direct replacements for 1A-rated designs.

Parameter Comparison

Part Number	Manufacturer	Output Current	Input Voltage (Max)	Dropout Voltage	Quiescent Current	PSRR (120Hz)	Operating Temp	Product Status	RoHS Status
MC7808ECT	onsemi	1A	35V	2V @ 1A	8 mA	73dB	0°C ~ 125°C	Obsolete	Not Specified
MC7808CTG	onsemi	1A	35V	2V @ 1A	8 mA	62dB	0°C ~ 125°C	Active	ROHS3 Compliant
MC7808ABTG	onsemi	1A	35V	2V @ 1A	6 mA	62dB	-40°C ~ 125°C	Obsolete	ROHS3 Compliant
L7808ACV-DG	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	62dB	0°C ~ 125°C	Active	ROHS3 Compliant
L7808ABV-DG	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	62dB	-40°C ~ 125°C	Obsolete	ROHS3 Compliant
L7808ABV	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	62dB	-40°C ~ 125°C	Obsolete	ROHS3 Compliant
L7808ACV	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	62dB	0°C ~ 125°C	Obsolete	ROHS3 Compliant
L7808CV	STMicroelectronics	1.5A	35V	2V @ 1A	8 mA	56dB	0°C ~ 125°C	Obsolete	ROHS3 Compliant
UA7808CKCS	Texas Instruments	1.5A	25V	2V @ 1A	Not Specified	72dB ~ 62dB	0°C ~ 125°C	Obsolete	ROHS3 Compliant
MC78M08CTG	onsemi	500mA	35V	Not Specified	Not Specified	80dB	0°C ~ 125°C	Obsolete	ROHS3 Compliant
MC78M08ABTG	onsemi	500mA	35V	Not Specified	Not Specified	80dB	-40°C ~ 125°C	Obsolete	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: MC7808CTG

The MC7808CTG is the preferred direct replacement for the MC7808ECT. Both parts are onsemi products with identical electrical specifications (1A output, 8V fixed, 35V maximum input, 2V dropout). The MC7808CTG holds Active product status and is RoHS3 compliant, providing long-term availability and regulatory compliance advantages over the obsolete MC7808ECT.

Secondary Recommendation: L7808ACV-DG

The L7808ACV-DG (STMicroelectronics) is an Active product offering 1.5A output current with identical voltage specifications and dropout characteristics. This part provides enhanced current capability while maintaining compatibility with MC7808ECT designs. RoHS3 compliance and active status ensure supply chain continuity.

Alternative for Extended Temperature Range: MC7808ABTG or L7808ABV-DG

For applications requiring operation from -40°C to 125°C, the MC7808ABTG (onsemi) or L7808ABV-DG (STMicroelectronics) extend the lower operating temperature limit. Both maintain 1A or 1.5A output current and identical voltage regulation characteristics.

Not Recommended for Direct Substitution: MC78M08CTG, MC78M08ABTG, UA7808CKCS

The MC78M08 series (500mA output) is unsuitable as a direct replacement for 1A applications. The UA7808CKCS (Texas Instruments) has a reduced maximum input voltage of 25V compared to the 35V specification of the MC7808ECT, limiting its use to lower input voltage designs.

Frequently Asked Questions (FAQ)

Q: Can I use L7808ACV-DG as a direct replacement for MC7808ECT?

A: Yes. The L7808ACV-DG provides identical 8V output voltage, 35V maximum input voltage, and 2V dropout voltage. The higher 1.5A output current rating is backward compatible with 1A applications. Pin configuration and TO-220-3 package are identical. Both parts include over temperature and short circuit protection.

Q: What is the difference between MC7808CTG and MC7808ECT?

A: Both are onsemi 8V, 1A linear regulators with identical electrical specifications. The primary difference is product status: MC7808ECT is obsolete while MC7808CTG is active. MC7808CTG includes RoHS3 compliance certification. Electrical performance and package are equivalent.

Q: Why does the UA7808CKCS have a lower maximum input voltage (25V vs 35V)?

A: The UA7808CKCS is a Texas Instruments design with different internal specifications. While it meets the 8V output and 1.5A current requirements, the 25V maximum input voltage limits its use to applications with lower input voltage rails. It is not suitable for designs requiring the full 35V input capability of the MC7808ECT.

Q: Can I use MC78M08CTG (500mA) instead of MC7808ECT (1A)?

A: No. The MC78M08CTG has half the output current rating (500mA vs 1A). Using it in a 1A application will cause the regulator to exceed its current limit and activate thermal shutdown protection. Use only in applications requiring 500mA or less.

Q: Are all substitute parts RoHS3 compliant?

A: Most substitute parts listed are RoHS3 compliant. The MC7808ECT does not specify RoHS status. If RoHS3 compliance is required, select from MC7808CTG, L7808ACV-DG, L7808ABV-DG, L7808ABV, L7808ACV, L7808CV, UA7808CKCS, MC78M08CTG, or MC78M08ABTG.

Q: What is the difference between L7808ACV and L7808ACV-DG?

A: Both are STMicroelectronics parts with identical electrical specifications (1.5A output, 8V fixed, 35V input, 2V dropout). The primary difference is product status: L7808ACV is obsolete while L7808ACV-DG is active. Both are RoHS3 compliant and use the same TO-220-3 package.

Q: Which substitute offers the best PSRR performance?

A: The MC78M08CTG and MC78M08ABTG offer the highest PSRR at 80dB (120Hz). However, these parts are rated for 500mA output only. Among 1A-rated parts, the MC7808ECT and MC7808CTG offer 73dB and 62dB respectively. The L7808CV offers 56dB PSRR among the 1.5A options.

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