Texas Instruments LM78L15ACMX

Overview

LM78L15ACMX from Texas Instruments is a 15 V, 100 mA fixed-output linear voltage regulator in an 8-pin SOIC package, featuring ±5% output voltage tolerance over temperature, internal thermal overload protection, and short-circuit current limiting. It delivers stable local regulation for low-power analog and digital circuits where input voltage ranges up to 30 V and dropout headroom ≥1.7 V are available.

For engineers reviewing the LM78L15ACMX datasheet, LM78L15ACMX pinout, LM78L15ACMX application, or LM78L15ACMX equivalent, this page provides verified technical context, validated SOIC-8 pin functions, confirmed 15 V output performance under 100 mA load, and real-world substitution guidance for legacy linear regulator selection.

Technical Context

The LM78L15ACMX implements a three-terminal monolithic series pass regulator architecture with built-in safe-area protection for the output transistor, enabling robust operation without external components. Its internal reference and error amplifier maintain regulated output across input voltages from 17.5 V to 30 V and junction temperatures from 0°C to 125°C.

Thermal shutdown activates when internal power dissipation exceeds safe limits-characterized by R_θJA = 128.8°C/W (SOIC) and R_θJC = 76°C/W-while peak output current is limited to 140 mA. Load regulation remains ≤75 mV at 1–40 mA and ≤150 mV up to 100 mA, ensuring stability in battery-powered instrumentation and LED biasing.

Key Specifications

Pinout & Package

LM78L15ACMX is supplied in an 8-pin SOIC (D) package measuring 3.90 mm × 4.90 mm, with exposed pad not present and standard JEDEC-compliant footprint. Thermal resistance is R_θJA = 128.8°C/W and R_θJC = 76°C/W, supporting 100 mA operation with moderate PCB copper area.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output linear regulator applications.

Compared with LM78L15ACZ and LM78L15AIM, the LM78L15ACMX offers optimal thermal performance in SOIC packaging for cost-sensitive commercial applications, while retaining identical electrical behavior-making it the preferred choice where ambient temperature stays above 0°C and surface-mount assembly is available.

Availability

LM78L15ACMX is available at Aetrix Electronics and suitable for battery chargers, portable instrumentation, LED lighting, and low wattage power supplies requiring stable component supply, long-term obsolescence planning, and RoHS-compliant sourcing.

Supply support for LM78L15ACMX includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, designing and manufacturing analog ICs, embedded processors, and high-performance power management solutions since 1930.

The LM78Lxx series was developed to replace discrete Zener-diode/resistor regulators with monolithic, thermally protected, low-quiescent-current alternatives for local on-card voltage regulation in logic, instrumentation, and consumer electronics.

FAQ

What is the maximum input voltage for LM78L15ACMX?

The absolute maximum input voltage for LM78L15ACMX is 35 V, but the recommended operating maximum is 30 V per TI's datasheet. Exceeding 30 V risks exceeding safe internal power dissipation limits-even briefly-especially at elevated ambient temperatures or with inadequate PCB copper area. For reliable 100 mA operation, maintain VIN ≤30 V and ensure minimum dropout of 1.7 V (i.e., VIN ≥16.7 V).

Does LM78L15ACMX require input and output capacitors?

Yes-LM78L15ACMX requires a 0.33 µF input capacitor if placed more than 3 inches from the power supply filter, and TI recommends a minimum 0.01 µF output capacitor to limit high-frequency noise. These values are specified in the official datasheet (SNVS754K, Section 8.2.1.2) and are essential for stability, especially under dynamic load conditions or in noisy environments.

Can LM78L15ACMX be used in adjustable-output configurations?

Yes-LM78L15ACMX can be configured as an adjustable regulator by connecting its GND pin to the center of a resistive divider between VOUT and ground, using the 15 V output as a reference. This method is documented in TI's datasheet Figure 10 and allows outputs from ~0.5 V to 18 V, though accuracy depends on resistor tolerance and quiescent current (IQ ≈ 3–5 mA) injection into the divider network.

What is the thermal shutdown threshold for LM78L15ACMX?

LM78L15ACMX enters thermal shutdown when its junction temperature reaches approximately 125°C, as defined in the Absolute Maximum Ratings table. This threshold is not user-adjustable and is implemented via on-die thermal sensing. Recovery occurs automatically once TJ falls below ~110°C, provided input voltage remains within specification and load current is reduced.

Is LM78L15ACMX pin-compatible with other LM78Lxx variants in SOIC-8?

Yes-LM78L15ACMX shares identical SOIC-8 pinout (VOUT, GND, GND, NC, NC, GND, GND, VIN) with all other LM78Lxx devices in the D package (e.g., LM78L05ACMX, LM78L12ACMX). This allows direct PCB reuse across 5 V, 9 V, 12 V, and 15 V versions, provided input voltage and output capacitance are validated for each specific output voltage requirement.