LM78L12ACZ Equivalent & Substitute Parts

Part Overview

The LM78L12ACZ is a linear voltage regulator IC manufactured by onsemi, designed to provide a fixed positive 12V output at 100mA. This through-hole component operates across an input voltage range up to 35V and includes integrated over-temperature and short-circuit protection. The part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	12V
Output Current	100mA
Input Voltage (Max)	35V
Output Configuration	Positive
Number of Regulators	1
Package Type	TO-92-3 (TO-226-3)
Mounting Type	Through Hole
Operating Temperature Range	-40°C to 125°C
Protection Features	Over Temperature, Short Circuit

Substitute Part Grouping Explanation

Substitution for the LM78L12ACZ is determined by strict equivalence across the following electrical and mechanical parameters:

Fixed output voltage of 12V
Output current capability of 100mA
Maximum input voltage of 35V or greater
Positive output configuration
Single regulator topology
TO-92-3 package compatibility
Through-hole mounting

Parts are grouped into two categories: direct substitutes (functionally equivalent across all critical parameters) and similar alternatives (compatible but with minor parameter variations such as operating temperature range or quiescent current specifications).

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Quiescent Current (Iq)	Operating Temperature	Product Status	Package
LM78L12ACZ	onsemi	12V	100mA	35V	6 mA	-40°C to 125°C	Obsolete	TO-92-3
MC78L12ABPRPG	onsemi	12V	100mA	35V	6.5 mA	-40°C to 125°C	Active	TO-92-3
MC78L12ACPRAG	onsemi	12V	100mA	35V	6.5 mA	0°C to 125°C	Active	TO-92-3
MC78L12ACPREG	onsemi	12V	100mA	35V	6.5 mA	0°C to 125°C	Active	TO-92-3
MC78L12ACPRMG	onsemi	12V	100mA	35V	6.5 mA	0°C to 125°C	Active	TO-92-3
MC78L12ACPRPG	onsemi	12V	100mA	35V	6.5 mA	0°C to 125°C	Active	TO-92-3
MC78L12ABPG	onsemi	12V	100mA	35V	6.5 mA	-40°C to 125°C	Active	TO-92-3
MC78L12ACPG	onsemi	12V	100mA	35V	6.5 mA	0°C to 125°C	Active	TO-92-3
NCV78L12ABPG	onsemi	12V	100mA	35V	6.5 mA	-40°C to 125°C	Active	TO-92-3
UA78L12ACLPE3	Texas Instruments	12V	100mA	27V	—	0°C to 125°C	Obsolete	TO-92-3
L78L12ABZ	STMicroelectronics	12V	100mA	35V	6 mA	-40°C to 125°C	Active	TO-92-3

Engineering Selection Recommendations

Primary Substitutes (onsemi MC78L12 Series)

The MC78L12ABPRPG, MC78L12ABPG, and L78L12ABZ are the most direct substitutes for the LM78L12ACZ. These parts maintain full electrical equivalence with identical output voltage, current rating, and input voltage specifications. MC78L12ABPRPG and MC78L12ABPG preserve the full -40°C to 125°C operating temperature range of the original part and are currently in active production status with substantial inventory availability.

Extended Temperature Range Consideration

Applications requiring the full -40°C to 125°C operating range should prioritize MC78L12ABPRPG, MC78L12ABPG, NCV78L12ABPG, or L78L12ABZ. The NCV78L12ABPG variant includes AEC-Q100 automotive qualification, suitable for automotive-grade applications.

Reduced Temperature Range Alternatives

MC78L12ACPRAG, MC78L12ACPREG, MC78L12ACPRMG, MC78L12ACPRPG, and MC78L12ACPG operate across 0°C to 125°C. These parts are appropriate for applications where the lower temperature limit does not extend below 0°C.

Cross-Manufacturer Option

The UA78L12ACLPE3 from Texas Instruments is functionally compatible but operates at a reduced maximum input voltage of 27V compared to the 35V specification of the LM78L12ACZ. This part is obsolete and should be considered only when inventory constraints require cross-manufacturer sourcing.

Packaging and Inventory

All substitute parts maintain TO-92-3 through-hole package compatibility. MC78L12ABPG offers the highest inventory availability at 689,288 pieces. For cut-tape packaging, MC78L12ACPRPG (1,860 pieces) and MC78L12ACPREG (2,693 pieces) are available.

Frequently Asked Questions (FAQ)

Q: Can MC78L12ACPRAG replace LM78L12ACZ in all applications?

A: MC78L12ACPRAG is electrically equivalent across voltage and current specifications. However, it operates at 0°C to 125°C versus the original -40°C to 125°C range. Use this part only if your application does not require operation below 0°C.

Q: What is the difference between MC78L12ABPRPG and MC78L12ACPRPG?

A: Both parts are functionally equivalent in electrical performance. MC78L12ABPRPG operates across -40°C to 125°C, while MC78L12ACPRPG operates across 0°C to 125°C. The "AB" designation indicates the extended temperature range variant.

Q: Is the NCV78L12ABPG suitable for non-automotive applications?

A: Yes. The NCV78L12ABPG meets AEC-Q100 automotive qualification but functions identically to standard industrial-grade equivalents. It is suitable for any application requiring the specified electrical and thermal characteristics.

Q: Why does UA78L12ACLPE3 have a lower maximum input voltage?

A: The UA78L12ACLPE3 is a Texas Instruments design with a 27V maximum input specification versus 35V for onsemi parts. This represents a design variation between manufacturers and limits its use to applications where input voltage remains below 27V.

Q: Are all substitute parts available in the same packaging options?

A: No. The LM78L12ACZ was supplied in standard TO-92-3 through-hole packaging. Substitute parts are available in bulk, cut-tape, and reel packaging depending on the specific part number. Verify packaging availability with your supplier for your procurement method.

Q: What is the significance of the quiescent current difference between LM78L12ACZ (6 mA) and MC78L12 variants (6.5 mA)?

A: The 0.5 mA difference in quiescent current is within normal manufacturing tolerance for this component class and does not affect functional compatibility. Both values are acceptable for standard linear regulator applications.

Q: Can I use L78L12ABZ as a direct replacement?

A: Yes. The L78L12ABZ from STMicroelectronics is a direct functional equivalent with identical electrical specifications and the same -40°C to 125°C operating range. It is currently in active production with good inventory availability.

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