STMicroelectronics L78L15ABZ-AP

Overview

L78L15ABZ-AP from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 15 V output at up to 100 mA, with ±4% output voltage tolerance (A-grade), thermal overload protection, short-circuit protection, and no external components required. It operates across -40 °C to +125 °C junction temperature and supports input voltages up to 30 V for 15 V output, making it suitable for local on-card regulation in industrial control modules and embedded sensor interfaces.

For engineers reviewing the L78L15ABZ-AP datasheet, L78L15ABZ-AP pinout, L78L15ABZ-AP application, or L78L15ABZ-AP equivalent, this device serves as a robust, drop-in replacement for Zener diode/resistor regulators-offering lower quiescent current (6.5 mA typ.), improved line/load regulation (250 mV/75 mV max), higher supply voltage rejection (34–39 dB), and integrated protection without external circuitry.

Technical Context

The L78L15ABZ-AP implements a monolithic silicon-based linear regulation architecture with internal current limiting, thermal shutdown, and safe-area protection-enabling operation without external compensation or stability components. Its design targets low-noise, low-power fixed-voltage local regulation where reliability under transient overloads and ambient extremes is critical.

It functions as a single-point, non-adjustable positive voltage source with dropout voltage of 1.7 V (typ.) at 40 mA, output noise of 90 µV RMS (10 Hz–100 kHz), and supply voltage rejection of 34–39 dB at 120 Hz-optimized for noise-sensitive analog front-ends and microcontroller power domains requiring stable 15 V bias.

Key Specifications

Pinout & Package

Supplied in TO-92 package (3-pin, vertical mounting), with lead-free ECOPACK compliance and Pb-free plating. Package dimensions: 4.95 mm × 3.94 mm × 15.49 mm (L×W×H), weight ~0.3 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L15ACZ/NOPB and MC78L15ACP, the L78L15ABZ-AP provides tighter output tolerance, guaranteed operation down to -40 °C junction, lower noise, and ST's industrial-grade process-making it optimal for new designs demanding reliability across harsh environments.

Availability

L78L15ABZ-AP is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical sensor signal conditioning, and test & measurement front-ends requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for L78L15ABZ-AP 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 microcontrollers, power management ICs, and analog devices for industrial, automotive, and consumer markets.

The L78L series belongs to ST's legacy linear regulator product line, engineered specifically for cost-sensitive, high-reliability local regulation in space-constrained embedded systems-emphasizing robustness, ease of use, and wide temperature operation without external components.

FAQ

What is the maximum input voltage for reliable operation of L78L15ABZ-AP?

The absolute maximum input voltage is 30 V DC when regulating 15 V output, as specified in Table 1 of DS0424 Rev 30. Operation above this risks permanent damage due to internal junction breakdown. For sustained reliability, maintain input ≤28.5 V under worst-case conditions (e.g., 120 Hz ripple peak + line surge) to preserve margin against thermal runaway.

Can L78L15ABZ-AP be used in parallel to increase output current?

No-parallel connection is not recommended. The L78L15ABZ-AP lacks current-sharing capability or built-in balancing features. Mismatched output voltages between units would cause one device to dominate conduction, leading to thermal imbalance and premature failure. Use a single higher-current regulator (e.g., L7815CV) or external pass transistor configuration instead.

Is an input bypass capacitor required for stable operation?

Yes-an input capacitor (minimum 0.33 µF ceramic) is mandatory per Figure 13 and Section 6 of DS0424. It suppresses high-frequency noise and prevents oscillation caused by source inductance. Omitting it risks instability, especially with long input traces or switching supply sources, and may trigger false thermal shutdown during transient load steps.

Does L78L15ABZ-AP support reverse-polarity input protection?

No-reverse input voltage (V_IN < GND) is not protected. Applying negative voltage to Pin 1 can damage the internal pass transistor and bandgap reference. External protection (e.g., series Schottky diode or polarity-reversal MOSFET circuit) must be added if system-level reverse connection is possible during service or assembly.