Texas Instruments LM79L05ACZ/NOPB

Overview

LM79L05ACZ/NOPB from Texas Instruments is a fixed-output, 3-terminal negative linear voltage regulator delivering −5 V at up to 100 mA, with ±5% output voltage accuracy over load, line, and temperature. It features internal short-circuit, thermal, and safe operating area protection, and is optimized for low-noise analog and dual-rail power supply applications in industrial control and instrumentation.

For engineers reviewing the LM79L05ACZ/NOPB datasheet, LM79L05ACZ/NOPB pinout, LM79L05ACZ/NOPB application, or LM79L05ACZ/NOPB equivalent, key selection criteria include guaranteed −5 V output tolerance, 0.01% load regulation, 0.07% line regulation, 40 μV RMS output noise (10 Hz–10 kHz), and compatibility with a minimal 0.1 μF output capacitor for stability.

Technical Context

The LM79L05ACZ/NOPB implements a monolithic PNP pass transistor architecture with built-in current limiting, thermal shutdown, and SOA protection-enabling robust operation without external components under transient overload or elevated ambient conditions. Its design targets stable DC biasing in op-amp circuits, sensor signal conditioning, and legacy analog systems requiring precise negative rail generation.

It operates across 0°C to +70°C and requires an input voltage between −7.0 V and −20 V to maintain regulation. The device exhibits 50 dB ripple rejection at 120 Hz and maintains ≤125 mV dropout voltage at full 100 mA load, making it suitable for moderate headroom applications where efficiency is secondary to precision and simplicity.

Key Specifications

Pinout & Package

LM79L05ACZ/NOPB is housed in a TO-92 (LP) 3-lead through-hole package with straight leads, 5.34 mm max height, and RoHS-compliant matte tin (Sn) lead finish. Pin 1 is emitter (−VIN), Pin 2 is collector (GND), Pin 3 is base (−VOUT), per JEDEC TO-226 standard.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar negative voltage regulation applications.

Compared with LM79L05ACZ/NOPB, the SOIC-packaged LM79L05ACM/NOPB offers superior manufacturability but reduced thermal margin, while the MC79L05ACP provides second-source assurance with minor spec trade-offs in regulation tightness and IQ consistency.

Availability

LM79L05ACZ/NOPB is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, legacy analog test equipment, medical diagnostic front-ends, and audio preamp biasing requiring stable component supply and long-term obsolescence mitigation.

Supply support for LM79L05ACZ/NOPB 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 leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in power management ICs and industrial-grade linear regulators.

The LM79LXXAC series was engineered specifically for cost-sensitive, space-constrained analog systems needing reliable fixed negative voltage regulation-emphasizing simplicity, protection integrity, and compatibility with legacy 3-terminal regulator footprints.

FAQ

What is the minimum input voltage required for LM79L05ACZ/NOPB to maintain regulation?

The LM79L05ACZ/NOPB requires a minimum input voltage of −7.0 V at 40 mA load and −7.3 V at 100 mA load to sustain −5 V output regulation. Below this threshold, the device enters dropout, and output voltage drops linearly with input. This headroom ensures stable operation across temperature and load variations per the datasheet's electrical characteristics table.

Can LM79L05ACZ/NOPB be used with a 0.1 μF ceramic capacitor for stability?

Yes, the LM79L05ACZ/NOPB is explicitly characterized for stability with a 0.1 μF output capacitor-either ceramic or aluminum electrolytic-as stated in its Features section and Figure 1. This eliminates the need for larger, bulkier capacitors and simplifies layout in compact analog subsystems where board space is limited.

Does LM79L05ACZ/NOPB include thermal shutdown protection?

Yes, the LM79L05ACZ/NOPB integrates a thermal shutdown circuit that activates at approximately +125°C junction temperature, disabling output to prevent permanent damage. Recovery occurs automatically once the die cools below the hysteresis threshold. This protection is part of its self-contained safety architecture, requiring no external components.

Is LM79L05ACZ/NOPB pin-compatible with older LM79L05 variants?

Yes, LM79L05ACZ/NOPB maintains identical pinout (TO-92, Pin 1 = −VIN, Pin 2 = GND, Pin 3 = −VOUT), electrical specifications, and footprint as legacy LM79L05 versions. The "AC" suffix denotes improved initial accuracy (±5%), and "NOPB" confirms RoHS-compliant matte tin plating-making it a direct replacement in existing designs.

What is the maximum power dissipation of LM79L05ACZ/NOPB in the TO-92 package?

In still air, the LM79L05ACZ/NOPB (TO-92/LP) has θJA = 232°C/W and a maximum junction temperature of +125°C. With a 25°C ambient, maximum allowable power dissipation is (125 − 25)/232 ≈ 430 mW. At −5 V output and 100 mA load, typical dissipation is (|VIN| − 5 V) × 0.1 A-so VIN ≤ −9.3 V keeps dissipation within safe limits.