NJM78L08A Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The NJM78L08A is a linear voltage regulator IC manufactured by Nisshinbo Micro Devices Inc., designed to provide a fixed positive 8V 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 NJM78L08A is currently listed as obsolete. Due to its discontinued status and limited availability from original sources, identifying equivalent substitute parts is necessary for ongoing design support, maintenance, and production continuity. Substitute parts must maintain electrical compatibility across critical parameters including output voltage, output current, input voltage range, and thermal protection characteristics.

Key Parameters

Parameter	Value	Unit
Output Configuration	Positive	—
Output Type	Fixed	—
Number of Regulators	1	—
Voltage - Output (Min/Fixed)	8	V
Voltage - Input (Max)	30	V
Current - Output	100	mA
Current - Quiescent (Iq)	6	mA
PSRR (120Hz)	66	dB
Protection Features	Over Temperature, Short Circuit	—
Operating Temperature Range	-40 to 85	°C
Mounting Type	Through Hole	—
Package / Case	TO-226-3, TO-92-3	—

Substitute Part Grouping Explanation

Substitute parts for the NJM78L08A are qualified based on the following critical parameters:

Electrical Compatibility Requirements:

Fixed positive output voltage of 8V
Output current capability of 100mA minimum
Maximum input voltage of 23V or greater
Quiescent current of 6mA or less
Protection features including over-temperature and short-circuit protection
Through-hole mounting in TO-92-3 or equivalent TO-226-3 package

Substitution Logic: Two substitute parts meet these criteria: the MC78L08ABPG (onsemi) and the UA78L08ACLP (Texas Instruments). Both devices provide identical output voltage and current specifications, compatible package configurations, and equivalent protection features. Differences in maximum input voltage, PSRR performance, and operating temperature range are noted but do not prevent functional substitution in applications designed for the NJM78L08A.

Parameter Comparison

Parameter	NJM78L08A (Nisshinbo)	MC78L08ABPG (onsemi)	UA78L08ACLP (Texas Instruments)	Unit
Output Configuration	Positive	Positive	Positive	—
Output Type	Fixed	Fixed	Fixed	—
Voltage - Output (Min/Fixed)	8	8	8	V
Voltage - Input (Max)	30	30	23	V
Current - Output	100	100	100	mA
Current - Quiescent (Iq)	6	6	Not specified	mA
PSRR (120Hz)	66	57	46	dB
Protection Features	Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Current, Over Temperature, Reverse Polarity, Short Circuit	—
Operating Temperature Range	-40 to 85	-40 to 125	0 to 125	°C
Mounting Type	Through Hole	Through Hole	Through Hole	—
Package / Case	TO-226-3, TO-92-3	TO-226-3, TO-92-3	TO-226-3, TO-92-3	—
Product Status	Obsolete	Active	Obsolete	—
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

MC78L08ABPG (onsemi) - Primary Substitute: The MC78L08ABPG is the preferred substitute for the NJM78L08A. This device maintains all critical electrical parameters including 8V fixed output, 100mA output current, and 30V maximum input voltage. The MC78L08ABPG carries Active product status, ensuring long-term availability and supply chain stability. It is ROHS3 compliant, meeting modern environmental and regulatory requirements. The extended operating temperature range (-40°C to 125°C) provides broader thermal performance compared to the original part. Inventory availability is substantial at 2274 pieces.

UA78L08ACLP (Texas Instruments) - Secondary Substitute: The UA78L08ACLP provides equivalent electrical functionality with identical output voltage and current specifications. This device includes enhanced protection features (over-current and reverse-polarity protection) beyond the original part. However, the maximum input voltage is limited to 23V, which is lower than the NJM78L08A specification of 30V. The UA78L08ACLP is also listed as obsolete. ROHS3 compliance is confirmed. This substitute is suitable for applications where the 23V input limit is acceptable and the additional protection features provide design benefit.

Compliance Considerations: Both substitute parts are ROHS3 compliant, addressing regulatory requirements not met by the original NJM78L08A. Selection between substitutes should prioritize the MC78L08ABPG for new designs and applications requiring maximum input voltage tolerance, and the UA78L08ACLP for applications where enhanced protection features and lower input voltage limits are acceptable.

Frequently Asked Questions (FAQ)

Q: Can the MC78L08ABPG directly replace the NJM78L08A in existing designs?

A: Yes. The MC78L08ABPG maintains identical output voltage (8V), output current (100mA), and package configuration (TO-92-3). All three devices share the same pinout and electrical interface. No circuit modifications are required for direct substitution.

Q: What is the difference in PSRR between the NJM78L08A and its substitutes?

A: The NJM78L08A specifies 66dB PSRR at 120Hz. The MC78L08ABPG provides 57dB, and the UA78L08ACLP provides 46dB. PSRR (Power Supply Rejection Ratio) measures the regulator's ability to reject input voltage ripple. Lower PSRR values indicate reduced ripple rejection performance. Applications requiring high ripple rejection should account for this difference.

Q: Why is the UA78L08ACLP limited to 23V maximum input voltage?

A: The UA78L08ACLP is specified with a 23V maximum input voltage, compared to 30V for the NJM78L08A and MC78L08ABPG. This is a design characteristic of the Texas Instruments device. Applications operating at input voltages between 23V and 30V must use the MC78L08ABPG or verify that the UA78L08ACLP is suitable for their specific input voltage range.

Q: Are the substitute parts available in the same package?

A: Yes. All three devices are available in TO-92-3 (TO-226-3) through-hole packages. Physical dimensions and pinout are compatible, enabling direct board-level substitution without layout modifications.

Q: What is the significance of RoHS compliance for these parts?

A: The NJM78L08A is RoHS non-compliant, while both MC78L08ABPG and UA78L08ACLP are ROHS3 compliant. RoHS3 compliance indicates the device meets restrictions on hazardous substances. For applications subject to environmental regulations or customer requirements mandating RoHS compliance, the substitute parts provide regulatory alignment.

Q: How do the operating temperature ranges compare?

A: The NJM78L08A operates from -40°C to 85°C. The MC78L08ABPG extends this range to -40°C to 125°C, providing broader thermal performance. The UA78L08ACLP operates from 0°C to 125°C, with a higher minimum temperature. Applications requiring operation below 0°C must use the NJM78L08A or MC78L08ABPG.

Q: What additional protection features does the UA78L08ACLP provide?

A: The UA78L08ACLP includes over-current, over-temperature, reverse-polarity, and short-circuit protection. The NJM78L08A and MC78L08ABPG provide over-temperature and short-circuit protection. The reverse-polarity protection in the UA78L08ACLP offers additional circuit safeguarding in applications where input polarity errors are a concern.

Q: Is the quiescent current specification identical across all three devices?

A: The NJM78L08A and MC78L08ABPG both specify 6mA quiescent current. The UA78L08ACLP does not provide a quiescent current specification in the available data. For applications where quiescent current is a critical design parameter, the MC78L08ABPG provides confirmed specification matching the original part.

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