KA7808AE Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The KA7808AE 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 package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The KA7808AE serves applications requiring stable 8V regulation from input sources up to 35V with integrated over-temperature and short-circuit protection.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	8V
Output Current	1A
Input Voltage (Max)	35V
Voltage Dropout (Max)	2V @ 1A (Typ)
Quiescent Current	6 mA
PSRR	62dB (120Hz)
Protection Features	Over Temperature, Short Circuit
Operating Temperature	0°C ~ 125°C
Package / Case	TO-220-3
Mounting Type	Through Hole

Substitute Part Grouping Explanation

Substitution for the KA7808AE is determined by the following critical parameters:

Output Voltage: Must be fixed at 8V
Output Current Capability: Minimum 1A required for direct substitution; parts rated at 1.5A or higher are compatible
Input Voltage Range: Maximum 25V to 35V acceptable
Package Type: TO-220-3 or TO-220 compatible
Protection Features: Over-temperature and short-circuit protection required
Operating Temperature Range: 0°C minimum to 125°C maximum

Substitute parts are grouped into two categories:

Category 1 - Direct Equivalents (1A Output): MC7808CTG, MC7808ABTG, and UA7808CKCS provide identical 1A output current with matching electrical characteristics.

Category 2 - Higher Current Alternatives (1.5A Output): L7808ABV, L7808ABV-DG, L7808ACV, L7808ACV-DG, and L7808CV offer 1.5A output capacity, providing additional design margin while maintaining 8V fixed output and compatible TO-220 packaging.

Category 3 - Lower Current Alternatives (500mA Output): MC78M08ABTG and MC78M08CTG provide 500mA output, suitable only for applications with reduced current requirements.

Parameter Comparison

Part Number	Manufacturer	Output Current	Input Voltage (Max)	Dropout Voltage	Quiescent Current	PSRR (120Hz)	Operating Temp	Product Status	Package
KA7808AE	onsemi	1A	35V	2V @ 1A	6 mA	62dB	0°C ~ 125°C	Obsolete	TO-220-3
MC7808CTG	onsemi	1A	35V	2V @ 1A	8 mA	62dB	0°C ~ 125°C	Active	TO-220-3
MC7808ABTG	onsemi	1A	35V	2V @ 1A	6 mA	62dB	-40°C ~ 125°C	Obsolete	TO-220-3
L7808ABV	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	62dB	-40°C ~ 125°C	Obsolete	TO-220-3
L7808ABV-DG	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	62dB	-40°C ~ 125°C	Obsolete	TO-220-3
L7808ACV	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	62dB	0°C ~ 125°C	Obsolete	TO-220-3
L7808ACV-DG	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	62dB	0°C ~ 125°C	Active	TO-220-3
L7808CV	STMicroelectronics	1.5A	35V	2V @ 1A	8 mA	56dB	0°C ~ 125°C	Obsolete	TO-220-3
UA7808CKCS	Texas Instruments	1.5A	25V	2V @ 1A	Not specified	72dB ~ 62dB	0°C ~ 125°C	Obsolete	TO-220-3
MC78M08ABTG	onsemi	500mA	35V	Not specified	Not specified	80dB	-40°C ~ 125°C	Obsolete	TO-220-3
MC78M08CTG	onsemi	500mA	35V	Not specified	Not specified	80dB	0°C ~ 125°C	Obsolete	TO-220-3

Engineering Selection Recommendations

For Direct Replacement (1A Output Requirement)

MC7808CTG is the primary recommended substitute. It is manufactured by onsemi, maintains identical 1A output current and 8V fixed output voltage, and holds Active product status ensuring ongoing availability. The quiescent current increases from 6 mA to 8 mA, a negligible difference for most applications. This part is ROHS3 compliant and carries identical electrical specifications for dropout voltage and PSRR.

MC7808ABTG provides an alternative from onsemi with extended operating temperature range (-40°C to 125°C) and matches the original 6 mA quiescent current specification. However, it carries Obsolete product status, limiting long-term supply reliability.

For Higher Current Applications (1.5A Output Capability)

L7808ACV-DG is the recommended choice among 1.5A alternatives. Manufactured by STMicroelectronics with Active product status, it provides superior current capacity while maintaining identical 8V output, 2V dropout voltage, and 62dB PSRR. The higher current rating (1.5A vs 1A) offers design margin without electrical performance degradation. ROHS3 compliance and extensive inventory (1590 pcs) support production continuity.

L7808CV offers the largest available inventory (205,300 pcs) among all substitutes, though PSRR is reduced to 56dB and product status is Obsolete. This part is suitable for cost-sensitive applications where PSRR performance is not critical.

For Reduced Current Applications (500mA Output)

MC78M08CTG and MC78M08ABTG are suitable only when application current requirements do not exceed 500mA. Both provide enhanced PSRR (80dB) compared to the original specification. MC78M08CTG maintains the 0°C to 125°C operating range matching the KA7808AE.

Compliance and Certification

All recommended substitutes maintain REACH Unaffected status and EAR99 ECCN classification, matching the original part's regulatory profile. ROHS3 compliance is confirmed for all active and recently obsolete parts. Moisture Sensitivity Level (MSL) is 1 (Unlimited) for all candidates, indicating no special handling requirements.

Frequently Asked Questions (FAQ)

Q: Can I use a 1.5A rated regulator as a direct replacement for the 1A KA7808AE?

A: Yes. The L7808ACV-DG, L7808ABV, L7808ABV-DG, and L7808CV are electrically compatible direct replacements. Higher current rating does not affect circuit operation at 1A load; it only provides additional design margin. All maintain 8V fixed output, identical dropout voltage, and compatible TO-220-3 packaging.

Q: What is the difference between L7808ACV-DG and L7808CV?

A: Both are STMicroelectronics 1.5A regulators with 8V output and TO-220-3 packaging. L7808ACV-DG is Active product status with 62dB PSRR, while L7808CV is Obsolete with 56dB PSRR. L7808ACV-DG is preferred for new designs due to active support and superior noise rejection. L7808CV offers significantly higher inventory availability.

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

A: UA7808CKCS is manufactured by Texas Instruments with different electrical specifications. While it provides 1.5A output and 8V regulation, the 25V maximum input voltage limits its use to applications with lower supply voltages. This part is not recommended for designs requiring the full 35V input range of the original KA7808AE.

Q: Are the 500mA alternatives (MC78M08CTG, MC78M08ABTG) suitable for my application?

A: Only if your circuit requires maximum 500mA output current. These parts provide superior PSRR (80dB) but cannot supply the full 1A available from the KA7808AE. Use these only when current requirements are confirmed below 500mA.

Q: What is the impact of quiescent current differences between substitutes?

A: Quiescent current (6 mA to 8 mA) represents standby power consumption with no load. The difference of 2 mA is negligible in most applications. For battery-powered or ultra-low-power designs, verify total system power budget, but this parameter alone does not disqualify any substitute.

Q: Can I mix different substitute parts in the same production run?

A: Yes, provided all selected parts meet your application's electrical requirements (output current, input voltage range, operating temperature). However, maintaining a single part number per design revision is recommended for supply chain consistency and traceability.

Q: What packaging differences exist between TO-220-3 and TO-220?

A: Both designations refer to the same three-pin through-hole package with identical pin spacing and thermal characteristics. The "-3" suffix in TO-220-3 explicitly indicates three pins. All substitutes listed are mechanically and electrically compatible in this package format.

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