KA7808ERTM Linear Voltage Regulator - Equivalent & Substitute Parts

Part Overview

The KA7808ERTM is a linear voltage regulator IC from onsemi designed to provide a fixed positive 8V output at 1A current capacity. It features a DPAK surface mount package with integrated over-temperature and short-circuit protection. The device operates across an input voltage range up to 35V with a maximum dropout voltage of 2V at full load.

The KA7808ERTM is classified as obsolete. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain flexibility, and support long-term product availability for applications currently using this regulator.

Key Parameters

Parameter	Value
Manufacturer Part Number	KA7808ERTM
Manufacturer	onsemi
Output Voltage (Fixed)	8V
Output Current	1A
Input Voltage (Max)	35V
Dropout Voltage (Max)	2V @ 1A (Typ)
Quiescent Current	8 mA
PSRR	73dB (120Hz)
Package / Case	TO-252-3, DPAK (2 Leads + Tab), SC-63
Operating Temperature	-40°C ~ 125°C
Protection Features	Over Temperature, Short Circuit
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the KA7808ERTM are grouped based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

Fixed output voltage of 8V
DPAK surface mount package (TO-252-3)
Positive output configuration
Operating temperature range compatibility
Protection features (over-temperature and short-circuit minimum)

Substitution Categories:

Parametric Equivalent (Full Replacement): Parts maintaining the 1A output current specification with identical electrical characteristics. NCV7808BDTRKG qualifies as a parametric equivalent, offering the same 1A output current, 2V dropout voltage, and -40°C to 125°C operating range. This part is automotive-grade (AEC-Q100 qualified) and carries active product status.

Similar Substitutes (Reduced Current Rating): Parts with 500mA output current instead of 1A. These include MC78M08BDTRKG, MC78M08CDTRKG, MC78M08BDTG, L78M08ABDT-TR, and L78M08CDT-TR. These maintain the 8V output, DPAK package, and core protection features but are suitable only for applications requiring ≤500mA output current.

Parameter Comparison

Parameter	KA7808ERTM	NCV7808BDTRKG	MC78M08BDTRKG	MC78M08CDTRKG	L78M08ABDT-TR	L78M08CDT-TR	MC78M08BDTG
Manufacturer	onsemi	onsemi	onsemi	onsemi	STMicroelectronics	STMicroelectronics	onsemi
Output Voltage	8V	8V	8V	8V	8V	8V	8V
Output Current	1A	1A	500mA	500mA	500mA	500mA	500mA
Input Voltage (Max)	35V	35V	35V	35V	35V	35V	35V
Dropout Voltage (Max)	2V @ 1A	2V @ 1A	—	—	—	—	—
Quiescent Current	8 mA	8 mA	—	—	6 mA	6 mA	—
PSRR (120Hz)	73dB	62dB	80dB	80dB	56dB	56dB	80dB
Package / Case	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK
Operating Temperature	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C	0°C ~ 125°C	-40°C ~ 125°C	0°C ~ 125°C	-40°C ~ 125°C
Protection Features	Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Temperature, Short Circuit
Product Status	Obsolete	Active	Active	Active	Active	Active	Obsolete
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Automotive Grade	—	Yes (AEC-Q100)	—	—	—	—	—

Engineering Selection Recommendations

For Direct 1A Replacement (Parametric Equivalent):

NCV7808BDTRKG is the primary choice for applications requiring the full 1A output current specification. This part maintains electrical equivalence with the KA7808ERTM, including identical dropout voltage (2V @ 1A) and quiescent current (8 mA). NCV7808BDTRKG carries active product status and ROHS3 compliance, ensuring long-term availability. The automotive-grade qualification (AEC-Q100) provides additional reliability assurance for demanding applications.

For 500mA Applications (Current-Limited Substitutes):

When application requirements permit reduced output current to 500mA, multiple active alternatives are available:

MC78M08BDTRKG and MC78M08BDTG (onsemi) offer superior PSRR performance (80dB) compared to the original part. MC78M08BDTRKG is packaged in Tape & Reel format with active status and ROHS3 compliance. MC78M08CDTRKG provides the same electrical performance but operates from 0°C to 125°C (narrower low-temperature range).

L78M08ABDT-TR and L78M08CDT-TR (STMicroelectronics) include over-current protection in addition to over-temperature and short-circuit protection. Both maintain active product status and ROHS3 compliance. L78M08ABDT-TR supports the full -40°C to 125°C temperature range, while L78M08CDT-TR operates from 0°C to 125°C.

Compliance Considerations:

All recommended substitutes are ROHS3 compliant and REACH unaffected. Parts with active product status (NCV7808BDTRKG, MC78M08BDTRKG, MC78M08CDTRKG, L78M08ABDT-TR, L78M08CDT-TR) are preferred for new designs and long-term supply assurance.

Frequently Asked Questions (FAQ)

Q: Can MC78M08BDTRKG replace KA7808ERTM in all applications?

A: MC78M08BDTRKG is suitable only for applications requiring ≤500mA output current. The KA7808ERTM is rated for 1A. If your application draws more than 500mA, use NCV7808BDTRKG instead. Both parts share the same 8V output, DPAK package, and operating temperature range.

Q: What is the difference between MC78M08BDTRKG and MC78M08CDTRKG?

A: Both parts are electrically identical with 500mA output current and 80dB PSRR. The primary difference is operating temperature range: MC78M08BDTRKG operates from -40°C to 125°C, while MC78M08CDTRKG operates from 0°C to 125°C. Select based on your minimum operating temperature requirement.

Q: Why does NCV7808BDTRKG have lower PSRR (62dB) than the original KA7808ERTM (73dB)?

A: PSRR values are provided in the specifications. NCV7808BDTRKG maintains the critical electrical parameters for 1A operation (output current, dropout voltage, quiescent current) and adds automotive-grade qualification. The PSRR difference does not affect functional substitution for standard 8V regulator applications.

Q: Are STMicroelectronics parts (L78M08 series) compatible with onsemi parts?

A: Yes. L78M08ABDT-TR and L78M08CDT-TR are functionally compatible substitutes for 500mA applications. All parts share the same DPAK package, 8V output voltage, 35V maximum input, and core protection features. STMicroelectronics parts include over-current protection as an additional feature.

Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging?

A: Both are surface mount packaging formats suitable for automated assembly. Cut Tape is supplied in individual strips, while Tape & Reel is supplied on continuous reels for high-volume production. Electrical performance is identical; packaging choice depends on your assembly process and volume requirements.

Q: Can I use a 500mA part in a circuit designed for 1A output?

A: No. Using a 500mA-rated regulator in a 1A application will cause the device to exceed its current rating, resulting in thermal stress, potential shutdown, or failure. Verify your actual current requirement before selecting a substitute. If your application requires 1A, use NCV7808BDTRKG.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All recommended active substitutes (NCV7808BDTRKG, MC78M08BDTRKG, MC78M08CDTRKG, L78M08ABDT-TR, L78M08CDT-TR) are ROHS3 compliant. The original KA7808ERTM compliance status is not specified in the provided data.

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