KA317 Linear Voltage Regulator IC Equivalent & Substitute Parts

Part Overview

The KA317 is a linear voltage regulator IC manufactured by onsemi, designed for positive adjustable output applications with 1.5A output current capability in a TO-220-3 package. The device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The KA317 operates across an input voltage range of up to 40V with adjustable output from 1.2V to 37V, incorporating over-temperature and short-circuit protection features suitable for power management applications requiring regulated DC output.

Key Parameters

Parameter	Value
Manufacturer Part Number	KA317
Manufacturer	onsemi
Category	Power Management (PMIC)
Package / Case	TO-220-3
Output Configuration	Positive
Output Type	Adjustable
Number of Regulators	1
Voltage - Input (Max)	40V
Voltage - Output (Min/Fixed)	1.2V
Voltage - Output (Max)	37V
Current - Output	1.5A
PSRR	75dB ~ 60dB (120Hz)
Protection Features	Over Temperature, Short Circuit
Operating Temperature	0°C ~ 125°C
Mounting Type	Through Hole
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the KA317 is determined by the following critical parameters:

Primary Substitution Criteria:

Output Configuration: Positive
Output Type: Adjustable
Package / Case: TO-220-3
Voltage - Input (Max): 40V
Voltage - Output Range: 1.2V to 37V minimum
Current - Output: 1.5A minimum
Mounting Type: Through Hole

Substitute parts are grouped into two categories based on output current capability:

Category 1: Direct Current Rating Match (1.5A Output) Parts with 1.5A output current provide direct functional equivalence to the KA317. These include LM317KCS, LM317KCSE3, LM317T, LM317T-BP, and LM317AT/NOPB. All maintain the same TO-220-3 package, positive adjustable output configuration, and 40V maximum input voltage specification.

Category 2: Reduced Current Rating (500mA Output) Parts with 500mA output current (LM317MABTG, LM317MBTG, LM317MTG) share the same voltage specifications and package but provide lower output current capability. These are suitable only for applications where the load current requirement does not exceed 500mA.

All substitute parts maintain the same base product number (LM317) and adjustable output voltage range, ensuring circuit-level compatibility when properly configured with external resistor networks.

Parameter Comparison

Parameter	KA317	LM317KCS	LM317KCSE3	LM317T	LM317T-BP	LM317AT/NOPB	LM317MABTG	LM317MBTG	LM317MTG
Manufacturer	onsemi	Texas Instruments	Texas Instruments	NTE Electronics, Inc	Micro Commercial Co	Texas Instruments	onsemi	onsemi	onsemi
Output Configuration	Positive	Positive	Positive	Positive	Positive	Positive	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable
Number of Regulators	1	1	1	1	1	1	1	1	1
Voltage - Input (Max)	40V	40V	40V	37V	40V	40V	40V	40V	40V
Voltage - Output (Min/Fixed)	1.2V	1.25V	1.25V	1.25V	1.25V	1.25V	1.2V	1.2V	1.2V
Voltage - Output (Max)	37V	37V	37V	37V	37V	37V	37V	37V	37V
Current - Output	1.5A	1.5A	1.5A	1.5A	1.5A	1.5A	500mA	500mA	500mA
Package / Case	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
PSRR	75dB ~ 60dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	64dB (120Hz)	-	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)
Protection Features	Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	-	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit
Operating Temperature	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C	0°C ~ 125°C
Product Status	Obsolete	Active	Last Time Buy	Active	Active	Active	Active	Active	Active
RoHS Status	-	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	-	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (1.5A Output Current Required):

LM317AT/NOPB (Texas Instruments) is the primary recommended substitute. It maintains full electrical equivalence with the KA317, provides 1.5A output current, operates across the same voltage range, and is actively produced with extensive inventory availability (634,378 pcs). The device is ROHS3 compliant and extends the operating temperature range to -40°C ~ 125°C, providing enhanced performance margin. The TO-220-3 package ensures mechanical compatibility without PCB redesign.

LM317KCS (Texas Instruments) provides equivalent 1.5A output current and voltage specifications with active product status. This part is suitable where Last Time Buy or extended temperature range is not a requirement.

LM317T (NTE Electronics, Inc) offers 1.5A output current and active product status. Note that the maximum input voltage specification is 37V compared to 40V for other alternatives, which may limit application flexibility in designs requiring the full 40V input range.

For Reduced Current Applications (500mA Output Current Acceptable):

LM317MBTG and LM317MABTG (onsemi) provide 500mA output current with active product status and ROHS3 compliance. These parts are suitable only for applications where load current does not exceed 500mA. Both maintain the same voltage specifications and TO-220-3 package as the KA317.

LM317MTG (onsemi) offers 500mA output current with active product status and operates across the 0°C ~ 125°C temperature range matching the KA317 specification.

Compliance Considerations:

All recommended substitutes are ROHS3 compliant except LM317T-BP. Parts with active product status (LM317AT/NOPB, LM317KCS, LM317T, LM317MBTG, LM317MABTG, LM317MTG) provide long-term supply assurance. LM317KCSE3 carries Last Time Buy status, indicating limited future availability.

Frequently Asked Questions (FAQ)

Q: Can LM317MBTG, LM317MABTG, or LM317MTG be used as direct replacements for KA317?

A: These parts share the same package, voltage specifications, and adjustable output configuration. However, they provide 500mA output current compared to the KA317's 1.5A capability. They are suitable only for applications where the maximum load current does not exceed 500mA. For applications requiring 1.5A output, use LM317AT/NOPB, LM317KCS, or LM317T instead.

Q: What is the difference between LM317KCS and LM317KCSE3?

A: Both parts are manufactured by Texas Instruments and provide identical electrical specifications: 1.5A output current, 40V maximum input voltage, and adjustable output from 1.25V to 37V. The primary difference is product status: LM317KCS is active, while LM317KCSE3 is Last Time Buy, indicating limited future availability. For new designs, LM317KCS is preferred.

Q: Is LM317T compatible with the KA317 in all applications?

A: LM317T provides 1.5A output current and the same TO-220-3 package. However, its maximum input voltage specification is 37V compared to 40V for the KA317 and other alternatives. In applications where input voltage may reach 40V, LM317AT/NOPB or LM317KCS are more appropriate choices.

Q: What is the significance of the operating temperature range difference between KA317 and LM317AT/NOPB?

A: The KA317 operates from 0°C to 125°C, while LM317AT/NOPB extends to -40°C to 125°C. The extended lower temperature range of LM317AT/NOPB provides additional design margin for applications in cold environments but does not affect functionality in the 0°C to 125°C range where both devices operate identically.

Q: Are all substitute parts ROHS3 compliant?

A: Most substitute parts are ROHS3 compliant (LM317KCS, LM317KCSE3, LM317T, LM317AT/NOPB, LM317MABTG, LM317MBTG, LM317MTG). LM317T-BP does not specify RoHS status. For applications requiring RoHS compliance certification, verify the specific part's documentation.

Q: Can I use LM317T-BP as a substitute?

A: LM317T-BP provides 1.5A output current and TO-220-3 package compatibility. However, it does not specify PSRR or protection features beyond the basic regulator function. It is suitable for applications where these specifications are not critical, but LM317AT/NOPB or LM317KCS are preferred for designs requiring documented protection features and PSRR performance.

Q: What inventory considerations should guide part selection?

A: LM317AT/NOPB has the highest inventory availability (634,378 pcs), ensuring long-term supply security. LM317MTG (9,660 pcs), LM317MBTG (6,375 pcs), and LM317KCSE3 (18,300 pcs) also maintain substantial stock levels. For critical applications, parts with higher inventory levels reduce supply chain risk.

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