KA7809ERTM Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The KA7809ERTM is a linear voltage regulator IC manufactured by onsemi, designed to provide a fixed positive 9V output at 1A current capacity in a DPAK surface mount package. This component is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The part operates across an industrial temperature range of -40°C to 125°C and includes integrated over-temperature and short-circuit protection features.

Key Parameters

Parameter	Value
Manufacturer Part Number	KA7809ERTM
Manufacturer	onsemi
Category	Power Management (PMIC)
Output Voltage (Fixed)	9V
Output Current	1A
Input Voltage (Max)	35V
Voltage Dropout (Max)	2V @ 1A (Typ)
Package / Case	TO-252-3, DPAK (2 Leads + Tab), SC-63
Mounting Type	Surface Mount
Operating Temperature	-40°C ~ 125°C
Product Status	Obsolete
Protection Features	Over Temperature, Short Circuit

Substitute Part Grouping Explanation

Substitution for the KA7809ERTM is determined by the following critical parameters:

Fixed output voltage of 9V
Package compatibility: TO-252-3 DPAK form factor
Surface mount mounting type
Positive output configuration
Operating temperature range support
Protection features: Over-temperature and short-circuit protection

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

Category A: Full Current Equivalents (1A Output) Parts maintaining the original 1A output current specification, suitable for direct replacement in applications requiring maximum current delivery.

Category B: Reduced Current Substitutes (500mA Output) Parts with 500mA output current, applicable in designs where lower current capacity is acceptable or where thermal management is improved through reduced power dissipation.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Package	Operating Temp	Product Status	Protection Features
KA7809ERTM	onsemi	9V	1A	35V	TO-252-3 DPAK	-40°C ~ 125°C	Obsolete	Over Temperature, Short Circuit
BA17809FP-E2	Rohm Semiconductor	9V	1A	26V	TO-252-3 DPAK	-40°C ~ 85°C	Active	None Specified
MC78M09BDTRKG	onsemi	9V	500mA	35V	TO-252-3 DPAK	-40°C ~ 125°C	Active	Over Temperature, Short Circuit
MC78M09CDTRKG	onsemi	9V	500mA	35V	TO-252-3 DPAK	0°C ~ 125°C	Active	Over Temperature, Short Circuit
MC78M09CDTG	onsemi	9V	500mA	35V	TO-252-3 DPAK	0°C ~ 125°C	Obsolete	Over Temperature, Short Circuit
L78M09ABDT-TR	STMicroelectronics	9V	500mA	35V	TO-252-3 DPAK	-40°C ~ 125°C	Active	Over Current, Over Temperature, Short Circuit
L78M09CDT-TR	STMicroelectronics	9V	500mA	35V	TO-252-3 DPAK	0°C ~ 125°C	Active	Over Current, Over Temperature, Short Circuit

Engineering Selection Recommendations

For Direct Replacement (1A Current Requirement): BA17809FP-E2 from Rohm Semiconductor is the only active substitute maintaining 1A output current. This part is ROHS3 compliant and actively manufactured. Note that the maximum input voltage is reduced to 26V compared to the original 35V specification, and the operating temperature range is limited to -40°C to 85°C. Verify that these parameter reductions are acceptable for the target application.

For Reduced Current Applications (500mA Acceptable): Multiple active substitutes are available from onsemi and STMicroelectronics. MC78M09BDTRKG and MC78M09CDTRKG from onsemi maintain full compatibility with the original -40°C to 125°C temperature range and 35V maximum input voltage. L78M09ABDT-TR and L78M09CDT-TR from STMicroelectronics provide additional over-current protection and are actively produced. All 500mA substitutes are ROHS3 compliant.

Obsolete Parts to Avoid: MC78M09CDTG and the original KA7809ERTM are obsolete and should not be selected for new designs despite potential availability in inventory.

Frequently Asked Questions (FAQ)

Q: Can MC78M09BDTRKG replace KA7809ERTM in all applications? A: MC78M09BDTRKG is a functional substitute if your application requires no more than 500mA output current. Both parts share identical input voltage (35V max), operating temperature range (-40°C to 125°C), package type (TO-252-3 DPAK), and protection features. If your circuit draws more than 500mA, this substitute is not suitable.

Q: What is the difference between MC78M09CDTRKG and MC78M09BDTRKG? A: Both parts are 500mA regulators in TO-252-3 DPAK packages from onsemi with identical electrical specifications. The primary difference is packaging: MC78M09BDTRKG is supplied in Cut Tape and Digi-Reel format, while MC78M09CDTRKG is supplied in Tape & Reel format. Additionally, MC78M09CDTRKG has a reduced operating temperature range starting at 0°C instead of -40°C.

Q: Why does BA17809FP-E2 have a lower maximum input voltage (26V vs 35V)? A: BA17809FP-E2 is manufactured by Rohm Semiconductor using different design specifications than the onsemi original. The 26V maximum input rating is a design parameter of this device. Confirm that your power supply voltage remains below 26V before selecting this substitute.

Q: Are all substitute parts RoHS compliant? A: All active substitute parts listed (BA17809FP-E2, MC78M09BDTRKG, MC78M09CDTRKG, L78M09ABDT-TR, L78M09CDT-TR) are ROHS3 compliant. The original KA7809ERTM and obsolete MC78M09CDTG do not specify RoHS status.

Q: What is the difference between L78M09ABDT-TR and L78M09CDT-TR? A: Both are 500mA linear regulators from STMicroelectronics in TO-252-3 DPAK packages with identical electrical performance. The key difference is operating temperature range: L78M09ABDT-TR operates from -40°C to 125°C, while L78M09CDT-TR operates from 0°C to 125°C. Select based on your minimum operating temperature requirement.

Q: Can I use a 500mA substitute in a design originally specified for 1A? A: Only if your actual circuit current draw does not exceed 500mA. Review your schematic and load analysis to confirm maximum current requirements. If peak or sustained current exceeds 500mA, use BA17809FP-E2 as the only active 1A equivalent.

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