STMicroelectronics L78L12ACD13TR

Overview

L78L12ACD13TR from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 12 V output at up to 100 mA, featuring ±4% output voltage tolerance (A grade), thermal overload protection, and short-circuit current limiting. It requires no external components and is designed for local on-card regulation in low-power embedded systems, sensor nodes, and industrial control modules where noise immunity and supply stability are critical.

For engineers reviewing the L78L12ACD13TR datasheet, L78L12ACD13TR pinout, L78L12ACD13TR application, or L78L12ACD13TR equivalent, this device serves as a drop-in replacement for legacy 78Lxx regulators in space-constrained PCBs requiring robust DC-DC conversion without switching noise - especially where input-to-output differential voltage remains ≥1.7 V and ambient temperature stays within 0–125 °C.

Technical Context

The L78L12ACD13TR integrates internal current limiting, thermal shutdown, and safe-area protection to prevent damage under fault conditions. Its architecture uses a PNP pass transistor with feedback-controlled base drive, enabling stable regulation without external compensation.

It operates across an input voltage range of 14.5 V to 27 V for guaranteed 12 V output, with dropout voltage specified at 1.7 V (typical) and load regulation of ≤50 mV over 1–40 mA output current. Quiescent current is 6.5 mA at 25 °C and drops to 6 mA at 125 °C, supporting thermally demanding environments.

Key Specifications

Pinout & Package

Supplied in SO-8 package with internally connected pins 2, 3, 6, and 7 tied to the die attach flag for enhanced thermal performance. Requires ≥6 cm² copper pour for optimal power dissipation (R_thJA = 55 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L12ACM/NOPB and MC78L12ACP, the L78L12ACD13TR offers tighter output tolerance, superior thermal dissipation via SO-8 flag bonding, and higher supply rejection - making it the preferred choice for new industrial and medical designs demanding reliability and noise resilience.

Availability

L78L12ACD13TR is available at Aetrix Electronics and suitable for industrial sensor nodes, PLC I/O modules, medical diagnostic peripherals, and smart energy meters requiring stable component supply with long-term lifecycle assurance.

Supply support for L78L12ACD13TR 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 since 1987.

The L78L series belongs to ST's legacy linear regulator product line, engineered specifically for cost-effective, robust local regulation in space- and reliability-constrained embedded systems - emphasizing fault tolerance over ultra-low quiescent current.

FAQ

What is the minimum input voltage required for stable 12 V output at full 100 mA load?

The L78L12ACD13TR requires a minimum input voltage of 13.7 V under worst-case conditions (125 °C junction, ±4% output tolerance, 100 mA load) to maintain regulation. At 25 °C, the dropout is 1.7 V, so 13.7 V ensures margin for line and load transients per Table 18 of DS0424 Rev 30.

Can this regulator be used in parallel to increase output current?

No - the L78L12ACD13TR lacks built-in current-sharing capability and has no output offset adjustment. Parallel connection risks thermal runaway due to mismatched dropout voltages and quiescent currents; ST recommends using a single higher-current regulator or external pass transistor instead.

Is the SO-8 package RoHS-compliant and halogen-free?

Yes - the L78L12ACD13TR SO-8 package meets RoHS Directive 2011/65/EU and is halogen-free per ST's ECOPACK2 specifications, with lead finish SnAgCu (SAC305) and matte tin plating over nickel underplate.

Does the device require input and output capacitors, and what values are recommended?

Yes - ST specifies a 0.33 µF ceramic capacitor at the input and a 0.1 µF ceramic capacitor at the output, placed as close as possible to the respective pins. These stabilize internal feedback and prevent oscillation; tantalum or aluminum electrolytics are not recommended due to ESR-related instability risks.