UA78M05CKCS Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The UA78M05CKCS is a linear voltage regulator IC manufactured by Texas Instruments, designed to provide a fixed positive 5V output at 500mA in a TO-220-3 through-hole package. This device is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. The regulator includes integrated protection features for over-current, over-temperature, and short-circuit conditions, making it suitable for general-purpose power supply applications requiring fixed 5V regulation.

Key Parameters

Parameter	Value
Manufacturer Part Number	UA78M05CKCS
Manufacturer	Texas Instruments
Output Voltage (Fixed)	5V
Output Current	500mA
Input Voltage (Max)	25V
Voltage Dropout (Max)	2V @ 350mA
Package / Case	TO-220-3
Mounting Type	Through Hole
Operating Temperature Range	0°C ~ 125°C
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the UA78M05CKCS is determined by the following critical parameters:

Fixed output voltage of 5V
Output current capability of 500mA or greater
Through-hole TO-220-3 package format
Maximum input voltage rating of 25V or higher
Protection features including over-current, over-temperature, and short-circuit protection
ROHS3 compliance

Substitute parts are grouped into three categories based on their relationship to the main part:

MFR Recommended Substitutes maintain identical or superior electrical specifications and package compatibility, with active product status from the original manufacturer or authorized equivalents.

Direct Manufacturer Equivalents provide functional equivalence from alternative manufacturers with matching package and performance characteristics.

Parametric Equivalents offer the same core functionality with minor specification variations that remain within acceptable operating parameters for typical applications.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Package	Mounting Type	Operating Temp Range	Product Status
UA78M05CKCS	Texas Instruments	5V	500mA	25V	TO-220-3	Through Hole	0°C ~ 125°C	Obsolete
LM341T-5.0/NOPB	Texas Instruments	5V	500mA	35V	TO-220-3	Through Hole	-40°C ~ 125°C	Active
LM78M05CT/NOPB	Texas Instruments	5V	500mA	35V	TO-220-3	Through Hole	-40°C ~ 125°C	Active
MC78M05CTG	onsemi	5V	500mA	35V	TO-220-3	Through Hole	0°C ~ 125°C	Active
MC78M05BTG	onsemi	5V	500mA	35V	TO-220-3	Through Hole	-40°C ~ 125°C	Active
L78M05ABV	STMicroelectronics	5V	500mA	35V	TO-220-3	Through Hole	-40°C ~ 125°C	Active
L78M05CV	STMicroelectronics	5V	500mA	35V	TO-220-3	Through Hole	0°C ~ 150°C	Active
AS7805AT-E1	Diodes Incorporated	5V	1A	25V	TO-220-3	Through Hole	-40°C ~ 125°C	Active
MC78M05ACTG	onsemi	5V	500mA	35V	TO-220-3	Through Hole	0°C ~ 125°C	Obsolete
UA78M05CKCSE3	Texas Instruments	5V	500mA	25V	TO-220-3	Through Hole	0°C ~ 125°C	Obsolete
TPS70950DBVT	Texas Instruments	5V	150mA	30V	SOT-23-5	Surface Mount	-40°C ~ 125°C	Active

Engineering Selection Recommendations

For applications requiring direct pin-compatible replacement in existing through-hole designs, select from active-status TO-220-3 package regulators: LM341T-5.0/NOPB, LM78M05CT/NOPB, MC78M05CTG, MC78M05BTG, L78M05ABV, or L78M05CV. These parts maintain identical package geometry and pinout while offering extended input voltage ratings (35V) compared to the original UA78M05CKCS specification.

The LM341T-5.0/NOPB and LM78M05CT/NOPB from Texas Instruments provide the closest functional equivalence with active product status and extended operating temperature range (-40°C to 125°C). Both are ROHS3 compliant and maintain the same manufacturer lineage as the obsolete UA78M05CKCS.

For applications where higher output current is acceptable, the AS7805AT-E1 from Diodes Incorporated provides 1A output capability in the same TO-220-3 package, maintaining compatibility with existing PCB layouts while offering increased current headroom.

The TPS70950DBVT represents a modern alternative for new designs where surface-mount technology is acceptable. This part requires PCB redesign due to its SOT-23-5 package but offers superior quiescent current performance (2.05 µA) and additional control features including enable functionality. However, its 150mA output current rating limits it to applications with lower current requirements than the original 500mA specification.

All recommended substitutes maintain ROHS3 compliance and are available in active production status, ensuring long-term supply chain reliability.

Frequently Asked Questions (FAQ)

Q: Can I use the TPS70950DBVT as a direct replacement for the UA78M05CKCS?

A: The TPS70950DBVT is not a direct replacement due to package incompatibility (SOT-23-5 surface mount versus TO-220-3 through hole) and reduced output current rating (150mA versus 500mA). It is suitable only for new designs where the lower current requirement is acceptable and surface-mount assembly is available.

Q: What is the key difference between LM341T-5.0/NOPB and LM78M05CT/NOPB?

A: Both parts provide identical 5V, 500mA output in TO-220-3 packages with 35V maximum input voltage and active product status. The primary difference is quiescent current specification: LM341T-5.0/NOPB specifies 4mA while LM78M05CT/NOPB specifies 3mA. Both are suitable direct replacements for the UA78M05CKCS.

Q: Why does the AS7805AT-E1 have a higher output current rating than the original part?

A: The AS7805AT-E1 is rated for 1A output current compared to the UA78M05CKCS 500mA rating. This higher capability does not prevent its use as a substitute; it simply provides additional current headroom. The part remains pin-compatible and maintains the same 5V output voltage and TO-220-3 package format.

Q: Are all substitute parts ROHS3 compliant?

A: All substitute parts listed in this document are ROHS3 compliant, matching the compliance status of the original UA78M05CKCS. This ensures compatibility with modern manufacturing and environmental regulations.

Q: What is the difference between through-hole and surface-mount packages for this application?

A: Through-hole packages (TO-220-3) are inserted into PCB holes and soldered from the back side, suitable for existing designs using through-hole assembly. Surface-mount packages (SOT-23-5) are soldered directly to PCB pads, requiring different assembly equipment and PCB layout. Direct replacement is only possible between parts using the same package type.

Q: Can I substitute an obsolete part with another obsolete part?

A: While MC78M05ACTG and UA78M05CKCSE3 are both obsolete, they provide functional equivalence to the UA78M05CKCS. However, active-status alternatives (LM341T-5.0/NOPB, LM78M05CT/NOPB, MC78M05CTG, L78M05ABV, L78M05CV) are preferred for new designs and ongoing production to ensure long-term supply availability.

Q: What input voltage range should I use for these regulators?

A: The UA78M05CKCS is rated for maximum 25V input. Most active substitutes (LM341T-5.0/NOPB, LM78M05CT/NOPB, MC78M05CTG, L78M05ABV, L78M05CV) support 35V maximum input, providing greater design flexibility. The AS7805AT-E1 maintains the 25V maximum input rating. Verify your specific application input voltage against the selected part's maximum rating.

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