NJM78L18A Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The NJM78L18A is a linear voltage regulator IC manufactured by Nisshinbo Micro Devices Inc., designed to provide a fixed positive 18V output at 100mA. This device is classified as a Power Management (PMIC) component and is packaged in TO-92-3 (TO-226-3) through-hole configuration. The NJM78L18A is currently listed as obsolete, making identification of active equivalent and substitute parts essential for ongoing design support and production continuity. Substitute parts must maintain electrical compatibility across output voltage, current capacity, and thermal protection characteristics while accommodating modern component availability and compliance requirements.

Substiute Parts

NJM78L18A

Nisshinbo Micro Devices Inc.In Stock: 3837NJM78L18A Datasheet

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AS78L15ZTR-E1

Diodes IncorporatedIn Stock: 10213AS78L15ZTR-E1 Datasheet

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MC78L18ABPG

onsemiIn Stock: 2224MC78L18ABPG Datasheet

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MC78L18ACPRAG

onsemiIn Stock: 2459MC78L18ACPRAG Datasheet

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MC78L18ACPRMG

onsemiIn Stock: 2807MC78L18ACPRMG Datasheet

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MC78L18ACPRPG

onsemiIn Stock: 2749MC78L18ACPRPG Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the NJM78L18A are evaluated based on the following critical parameters that determine functional compatibility:

Output Voltage Matching: The primary substitution criterion is fixed output voltage. The NJM78L18A provides 18V output. Substitute parts must deliver the same 18V output voltage to maintain circuit functionality.

Output Current Capacity: All qualified substitutes must support 100mA output current minimum, matching the original specification.

Package and Mounting: Physical compatibility requires TO-92-3 or TO-226-3 package configuration with through-hole mounting to ensure direct board-level replacement without redesign.

Protection Features: Over-temperature and short-circuit protection are mandatory in all substitutes to maintain circuit safety characteristics.

Input Voltage Rating: Maximum input voltage tolerance must accommodate the application's supply voltage range. The NJM78L18A accepts up to 40V input.

Quiescent Current: Standby current consumption should remain within acceptable limits for low-power applications.

Substitutes are grouped into two categories:

Category 1 - Direct Voltage Match (18V Output): MC78L18ABPG, MC78L18ACPRAG, MC78L18ACPRPG, MC78L18ACPRMG (onsemi). These parts provide identical 18V output voltage and are manufactured by onsemi with active product status and modern RoHS3 compliance.

Category 2 - Voltage Variant (15V Output): AS78L15ZTR-E1 (Diodes Incorporated). This part provides 15V output instead of 18V and is suitable only for applications where 15V output is acceptable. This represents a functional alternative for different voltage requirements, not a direct replacement.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (18V Output Required):

The onsemi MC78L18 series parts (MC78L18ABPG, MC78L18ACPRAG, MC78L18ACPRPG, MC78L18ACPRMG) are the primary substitutes for the obsolete NJM78L18A. All four parts maintain identical 18V output voltage and 100mA current capacity. These parts are currently in active production status with full RoHS3 compliance, addressing both component availability and modern regulatory requirements.

MC78L18ABPG is packaged in bulk and supports the full -40°C to 125°C operating temperature range, matching the lower temperature limit of the original NJM78L18A.

MC78L18ACPRAG, MC78L18ACPRPG, and MC78L18ACPRMG are supplied in cut tape packaging with operating temperature ranges of 0°C to 125°C. These variants are functionally equivalent and differ only in packaging format and minimum operating temperature specification.

All onsemi MC78L18 variants feature identical electrical performance: 6.5 mA quiescent current, 48dB PSRR at 120Hz, and 35V maximum input voltage. The 5V reduction in maximum input voltage (from 40V to 35V) relative to the NJM78L18A must be verified against the application's supply voltage specifications.

For Voltage-Variant Applications (15V Output Acceptable):

The AS78L15ZTR-E1 from Diodes Incorporated provides 15V output with 100mA capacity in TO-92-3 package. This part is suitable only for applications where 15V output voltage is functionally acceptable. The AS78L15ZTR-E1 features active product status, RoHS3 compliance, and extended -40°C to 125°C operating temperature range. PSRR performance is lower at 39dB compared to the original 59dB specification.

Compliance Considerations:

The NJM78L18A is RoHS non-compliant. All recommended substitutes (onsemi MC78L18 series and Diodes AS78L15ZTR-E1) are ROHS3 compliant, supporting modern manufacturing and environmental requirements.

Frequently Asked Questions (FAQ)

Q: Can MC78L18ABPG directly replace NJM78L18A without circuit modification?

A: Yes, MC78L18ABPG provides direct replacement capability. Both parts deliver 18V fixed output at 100mA in TO-92-3 package with identical quiescent current (6.5 mA) and equivalent protection features. The maximum input voltage is reduced from 40V to 35V; verify your application's supply voltage does not exceed 35V.

Q: What is the difference between MC78L18ACPRAG, MC78L18ACPRPG, and MC78L18ACPRMG?

A: These three parts are electrically identical with 18V output, 100mA capacity, and 6.5 mA quiescent current. The differences are packaging format (all cut tape) and minimum operating temperature (0°C vs. -40°C for MC78L18ABPG). Select based on your temperature requirements and packaging preference.

Q: Is AS78L15ZTR-E1 a suitable replacement for NJM78L18A?

A: AS78L15ZTR-E1 is not a direct replacement because it provides 15V output instead of 18V. Use this part only if your circuit can operate at 15V output voltage. It offers the advantage of active product status and RoHS3 compliance.

Q: What are the key electrical differences between NJM78L18A and the onsemi MC78L18 substitutes?

A: The primary difference is PSRR performance: NJM78L18A provides 59dB at 120Hz while MC78L18 variants provide 48dB. Maximum input voltage is reduced from 40V to 35V in the onsemi parts. Output voltage (18V), output current (100mA), and quiescent current (6.5 mA) are identical.

Q: Can I use MC78L18ACPRAG in applications requiring -40°C operation?

A: No. MC78L18ACPRAG minimum operating temperature is 0°C. For -40°C operation, use MC78L18ABPG which supports -40°C to 125°C range.

Q: Are all substitute parts available in the same TO-92-3 package?

A: Yes. All recommended substitutes (MC78L18ABPG, MC78L18ACPRAG, MC78L18ACPRPG, MC78L18ACPRMG, and AS78L15ZTR-E1) are packaged in TO-226-3 / TO-92-3 through-hole configuration, enabling direct board-level replacement without layout modification.

Q: What inventory status should I consider when selecting a substitute?

A: All recommended substitutes maintain active production status with substantial inventory availability. MC78L18ACPRMG has 2,756 pieces in stock, MC78L18ACPRPG has 2,724 pieces, MC78L18ACPRAG has 2,413 pieces, MC78L18ABPG has 2,200 pieces, and AS78L15ZTR-E1 has 10,200 pieces available.

Q: Does RoHS3 compliance affect circuit performance?

A: RoHS3 compliance addresses material composition and environmental requirements but does not alter electrical performance. All RoHS3-compliant substitutes maintain the same functional characteristics as the original NJM78L18A within their specified electrical parameters.