STMicroelectronics L78M10CDT

Overview

L78M10CDT from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a precise 10 V output at up to 500 mA, featuring ±2 % output voltage tolerance, thermal overload protection, and short-circuit protection in DPAK package. It provides local on-card regulation for embedded power rails in industrial control modules, sensor signal conditioning circuits, and low-power microcontroller supply domains.

For engineers reviewing the L78M10CDT datasheet, L78M10CDT pinout, L78M10CDT application, or L78M10CDT equivalent, key selection criteria include guaranteed extended temperature operation (0 to 125 °C), dropout voltage of 2 V at 25 °C, 56 dB supply voltage rejection at 120 Hz, 100 mV load regulation over 5–200 mA, and DPAK thermal resistance of 100 °C/W junction-to-ambient.

Technical Context

This device implements a monolithic silicon pass transistor with internal current limiting, thermal shutdown, and safe operating area (SOA) compensation-enabling robust operation under sustained overload or transient fault conditions. Its fixed-output architecture eliminates external feedback components while maintaining stability with minimal input/output capacitance (0.33 µF and 0.1 µF).

The L78M10CDT operates across an input voltage range of 12.5 V to 30 V for nominal 10 V output, with line regulation of 30 mV (typ.) and load regulation of 100 mV (max.) over full load range. Output noise is specified at 64 µV RMS (10 Hz–100 kHz), supporting noise-sensitive analog subsystems.

Key Specifications

Pinout & Package

DPAK (TO-252) surface-mount package with exposed thermal pad; footprint compliant with STD-ST, Fujitsu-subcon, and IDS-subcon mechanical variants per Doc ID 2147 Rev 9.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78M10CDT and MC78M10CDTG, the L78M10CDT offers tighter voltage tolerance and lower dropout-critical for maintaining regulation headroom and analog accuracy in compact industrial designs where board space and thermal management are constrained.

Availability

L78M10CDT is available at Aetrix Electronics and suitable for industrial sensor interface, microcontroller power supply, and programmable I/O module applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for L78M10CDT 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 analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The L78Mxx series belongs to ST's precision linear regulator product line, engineered for reliable local regulation in space-constrained industrial equipment where thermal robustness and output accuracy are prioritized over ultra-low quiescent current.

FAQ

What is the minimum input voltage required for stable 10 V output from L78M10CDT?

The minimum input voltage is 12.5 V under typical conditions (IO = 5–350 mA, TJ = 25 °C), based on its 2 V dropout specification. At higher temperatures or loads, VI must exceed 12.5 V to maintain regulation-derating curves in Figure 9 of Doc ID 2147 show dropout increases to ~2.3 V at 125 °C junction.

Can L78M10CDT be used with ceramic output capacitors?

Yes, but only with careful attention to ESR: the datasheet specifies 0.1 µF tantalum or aluminum electrolytic for stability. Ceramic capacitors with ESR < 0.1 Ω may cause oscillation; if used, add a 1 Ω damping resistor in series with the capacitor or select ceramics with ≥1 Ω effective series resistance.

Does L78M10CDT require an input bypass capacitor?

Yes-an input bypass capacitor ≥0.33 µF (tantalum, mylar, or low-ESR ceramic) is mandatory when connected via long traces or cables to a noisy supply. Mount it directly across pins 1 and 2 with shortest possible leads to prevent high-frequency instability and improve transient response.

How does thermal protection behave during sustained overload?

When junction temperature exceeds safe threshold (~165 °C), the device enters thermal shutdown-halting output until temperature falls by ~15 °C. Recovery is automatic and non-latching. This protects against permanent damage during prolonged short-circuit or excessive ambient conditions, as confirmed in Section 7.1 of the datasheet.