KA7905 Equivalent & Substitute Parts

Part Overview

The KA7905 is a linear voltage regulator IC manufactured by onsemi, providing a fixed negative output of -5V at 1A 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 KA7905 serves applications requiring negative voltage regulation with thermal and short-circuit protection in through-hole mounting configurations.

Key Parameters

Parameter	Value
Output Configuration	Negative
Output Type	Fixed
Output Voltage	-5V
Current Output	1A
Voltage Input (Max)	-35V
Voltage Dropout (Max)	2V @ 1A (Typ)
Package / Case	TO-220-3
Mounting Type	Through Hole
Operating Temperature	0°C ~ 125°C
Protection Features	Over Temperature, Short Circuit

Substitute Part Grouping Explanation

Substitution for the KA7905 is determined by the following critical parameters:

Output Configuration & Voltage: All substitutes must provide negative fixed -5V output
Current Rating: Minimum 1A output current required; higher ratings are acceptable
Package Type: TO-220-3 package maintains mechanical and thermal compatibility
Input Voltage Range: Maximum -35V input specification must be met or exceeded
Protection Features: Over temperature and short circuit protection required
Operating Temperature Range: 0°C to 125°C minimum specification

Substitute parts are grouped into two categories:

Direct Substitutes (MC7905BTG, MC7905CTG, L7905ACV, L7905ACV-DG, L7905CV, L7905CV-DG): These parts meet or exceed all critical parameters with identical or improved electrical characteristics and active product status.

Parametric Equivalents (LM7905CT/NOPB, UA7905CKCS, LM7905CT): These parts provide equivalent functionality with variations in input voltage range or quiescent current specifications.

Parameter Comparison

Part Number	Manufacturer	Output Current	Voltage Dropout (Max)	Input Voltage (Max)	Quiescent Current	PSRR (120Hz)	Product Status	RoHS Status
KA7905	onsemi	1A	2V @ 1A	-35V	6 mA	60dB	Obsolete	Not Specified
MC7905BTG	onsemi	1A	1.3V @ 1A	-35V	Not Specified	70dB	Active	ROHS3 Compliant
MC7905CTG	onsemi	1A	1.3V @ 1A	-35V	Not Specified	70dB	Active	ROHS3 Compliant
L7905ACV	STMicroelectronics	1.5A	1.4V @ 1A	-35V	3 mA	60dB	Active	ROHS3 Compliant
L7905ACV-DG	STMicroelectronics	1.5A	1.4V @ 1A	-35V	3 mA	60dB	Obsolete	ROHS3 Compliant
L7905CV	STMicroelectronics	1.5A	1.4V @ 1A	-35V	3 mA	60dB	Active	ROHS3 Compliant
L7905CV-DG	STMicroelectronics	1.5A	1.4V @ 1A	-35V	3 mA	60dB	Active	ROHS3 Compliant
LM7905CT/NOPB	Texas Instruments	1.5A	1.1V @ 1A	-25V	1 mA	66dB	Active	ROHS3 Compliant
UA7905CKCS	Texas Instruments	1.5A	1.1V @ 1A	-25V	Not Specified	60dB	Last Time Buy	ROHS3 Compliant
LM7905CT	Fairchild Semiconductor	1A	2V @ 1A	-35V	6 mA	60dB	Obsolete	Not Specified

Engineering Selection Recommendations

Primary Substitutes (Recommended for New Designs)

MC7905CTG and MC7905BTG from onsemi are active products with improved voltage dropout characteristics (1.3V vs. 2V) and enhanced PSRR (70dB vs. 60dB). Both maintain the -35V input specification and TO-220-3 package compatibility. MC7905CTG supports the full 0°C to 125°C operating range matching the original KA7905.

L7905CV and L7905CV-DG from STMicroelectronics are active products offering 1.5A output current with lower quiescent current (3 mA vs. 6 mA). These parts maintain -35V input rating and provide ROHS3 compliance with improved thermal efficiency.

Secondary Substitutes (For Existing Designs)

LM7905CT/NOPB from Texas Instruments is an active product with superior performance metrics including 1.1V dropout voltage and 1 mA quiescent current. However, the -25V maximum input voltage specification is more restrictive than the KA7905 -35V rating and must be verified for circuit compatibility.

UA7905CKCS from Texas Instruments carries Last Time Buy status, indicating limited future availability. This part shares the -25V input limitation with LM7905CT/NOPB.

Avoid for New Designs

L7905ACV-DG and LM7905CT are obsolete products. While functionally equivalent, their discontinued status makes them unsuitable for production designs requiring long-term supply assurance.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute with higher current rating than the KA7905?

A: Yes. Parts rated for 1.5A output current (L7905ACV, L7905CV, LM7905CT/NOPB, UA7905CKCS) are direct substitutes for 1A applications. The higher rating provides design margin without affecting circuit operation at 1A load.

Q: What is the impact of lower voltage dropout in substitute parts?

A: Lower dropout voltage (1.3V to 1.1V vs. 2V) improves power efficiency and reduces heat dissipation. This is a beneficial characteristic requiring no circuit modifications.

Q: Are all substitutes ROHS3 compliant?

A: All active and Last Time Buy products listed are ROHS3 compliant. The original KA7905 and obsolete LM7905CT do not specify RoHS status.

Q: Can I use LM7905CT/NOPB if my circuit requires -35V input?

A: No. LM7905CT/NOPB is rated for maximum -25V input. Using it in a -35V circuit exceeds the device specification and risks failure. Verify your actual input voltage requirement before selecting this part.

Q: What is the difference between MC7905BTG and MC7905CTG?

A: Both parts are electrically identical with identical electrical specifications. MC7905BTG supports -40°C to 125°C operating temperature, while MC7905CTG supports 0°C to 125°C. Select based on your minimum operating temperature requirement.

Q: Is the TO-220-3 package identical across all substitutes?

A: Yes. All listed parts use TO-220-3 package with identical pinout and mechanical dimensions, enabling direct board-level replacement without layout modifications.

Q: Why do some substitutes show lower quiescent current?

A: Improved semiconductor process technology in newer designs reduces quiescent current. L7905CV series (3 mA) and LM7905CT/NOPB (1 mA) consume less standby power than the original KA7905 (6 mA), benefiting battery-powered applications.

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