STMicroelectronics L78M10ACDT-TR

Overview

L78M10ACDT-TR from STMicroelectronics is a three-terminal positive fixed-voltage linear regulator delivering 10 V at up to 500 mA output current, with ±2 % output voltage tolerance over 0 to 125 °C junction temperature range. It features thermal overload protection, short-circuit protection, and safe operating area (SOA) compensation for robust local on-card regulation in industrial power rails and embedded subsystems.

For engineers reviewing the L78M10ACDT-TR datasheet, L78M10ACDT-TR pinout, L78M10ACDT-TR application, or L78M10ACDT-TR equivalent, key selection criteria include dropout voltage (2 V), supply voltage rejection (56 dB at 120 Hz), output noise (64 µV RMS), load regulation (200 mV over 5–500 mA), and DPAK package thermal resistance (R_thJA = 100 °C/W).

Technical Context

This regulator employs an internal NPN pass transistor with built-in current limiting, thermal shutdown, and SOA protection-eliminating external protection components. Its architecture supports stable operation without mandatory input/output capacitors in low-current applications but recommends ≥0.33 µF input and ≥0.1 µF output ceramic or tantalum bypassing for transient immunity and stability under variable loads.

It operates across a 12.5–25 V input range for 10 V output, maintaining regulation with ≤100 mV line regulation (VI = 12.5–30 V, IO = 200 mA) and ≤200 mV load regulation (IO = 5–500 mA). Quiescent current remains tightly controlled at 6 mA (typ), varying by only ±0.5 mA across full load and input voltage ranges.

Key Specifications

Pinout & Package

The L78M10ACDT-TR is housed in a surface-mount DPAK (TO-252) package with exposed thermal pad for enhanced heat dissipation. Pin assignment follows standard three-terminal regulator configuration: Input (Pin 1), Ground (Pin 2), Output (Pin 3).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78M10CDT-TR and MC78M10CDTG, the L78M10ACDT-TR offers superior output accuracy (±2 %), higher supply rejection (56 dB), and lower thermal resistance (100 °C/W), making it optimal for noise-sensitive industrial and medical applications requiring stable 10 V rails under variable load and input conditions.

Availability

L78M10ACDT-TR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical sensor interfaces, and point-of-sale display systems requiring stable component supply and long-term production continuity.

Supply support for L78M10ACDT-TR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing silicon solutions for automotive, industrial, and consumer markets.

The L78Mxx series belongs to ST's precision linear regulator product line, engineered for local on-card regulation in space-constrained industrial and embedded systems where reliability, thermal resilience, and output accuracy are critical.

FAQ

What is the minimum input voltage required for L78M10ACDT-TR to regulate at 10 V?

The minimum input voltage is 12.5 V, based on its 2 V dropout specification. At 25 °C junction temperature, the device maintains regulation as long as VI ≥ VO + V_d = 10 V + 2 V. Input voltage must remain ≥12.5 V under all load and temperature conditions to avoid dropout.

Can L78M10ACDT-TR be used without input and output capacitors?

Yes, in low-current, low-noise environments with short PCB traces and stable input sources, but ST recommends ≥0.33 µF input and ≥0.1 µF output capacitors. Omission risks instability, poor transient response, and increased output noise-especially with switching supply inputs or long wiring.

How does thermal performance differ between DPAK and TO-220 packages for this regulator?

The DPAK package has R_thJA = 100 °C/W versus TO-220's 50 °C/W. At 500 mA and 2 V dropout (1 W dissipation), DPAK junction temperature rises ~100 °C above ambient-requiring careful PCB copper area design. TO-220 allows higher continuous current without heatsinking but occupies more board space.

Is L78M10ACDT-TR qualified for automotive applications?

No-it is specified for 0 to 125 °C junction temperature (AC grade), not the −40 to 150 °C AEC-Q100 requirement. For automotive use, ST offers the L78M10AB variant (−40 to 125 °C) in same DPAK package, with identical electrical specs but extended temperature qualification.