Texas Instruments MC79L05CLP

Overview

MC79L05CLP from Texas Instruments is a fixed negative-voltage linear regulator delivering −5 V output at up to 100 mA, featuring internal thermal-overload protection and short-circuit current limiting in a TO-92 (LP) package. It requires no external components, supports input voltages from −7 V to −20 V, and maintains ±10% output voltage tolerance over 0°C to 125°C for on-card noise-sensitive regulation.

For engineers reviewing the MC79L05CLP datasheet, MC79L05CLP pinout, MC79L05CLP application, or MC79L05CLP equivalent, key selection criteria include dropout voltage (1.7 V at 40 mA), ripple rejection (40 dB at 120 Hz), bias current (6 mA typical), and thermal impedance (140°C/W in LP package) for low-power analog and embedded subsystems.

Technical Context

This device operates as a three-terminal monolithic negative-voltage regulator with a common-emitter pass transistor architecture. Its internal current-limiting and thermal-shutdown circuitry enable robust operation without external protection components, and it functions as a direct replacement for industry-standard MC79L00-series regulators.

The MC79L05CLP uses a fixed internal reference and error amplifier to regulate output voltage against line and load variations. Input regulation is specified at 200 mV over −7 V to −20 V, and output regulation remains within 60 mV across 1–100 mA load current at 25°C.

Key Specifications

Pinout & Package

MC79L05CLP is housed in a TO-92 (LP) through-hole package with 3 terminals and a maximum height of 5.34 mm. The package is Pb-Free (RoHS-compliant) with Sn lead finish and rated for 0°C to 125°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM79L05ACZ, MC79L05CLP offers superior ripple rejection and lower quiescent current but trades ±10% tolerance for cost and legacy compatibility; versus MC78L05CLP, it provides functional polarity inversion but cannot substitute in positive-rail designs without schematic revision.

Availability

MC79L05CLP is available at Aetrix Electronics and suitable for industrial sensor interfaces, legacy system power retrofits, and low-power embedded controllers requiring stable component supply and long-lifecycle support.

Supply support for MC79L05CLP 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 company specializing in analog, embedded processing, and connectivity technologies, with over 50 years of leadership in power management ICs.

The MC79L00 series was designed for cost-sensitive, low-current negative voltage regulation in industrial, automotive, and consumer electronics-emphasizing simplicity, reliability, and drop-in replaceability.

FAQ

What is the maximum input voltage rating for MC79L05CLP?

The absolute maximum input voltage for MC79L05CLP is −30 V. Exceeding this value risks permanent damage. For reliable operation, the recommended input range is −7 V to −20 V, ensuring sufficient headroom for the 1.7 V dropout voltage while maintaining regulation stability across temperature and load conditions. This range is validated in the datasheet's recommended operating conditions table.

Does MC79L05CLP require input and output capacitors?

Yes, MC79L05CLP requires a 0.33 µF capacitor across the input and a 0.1 µF capacitor across the output, as specified in the electrical characteristics test conditions. These capacitors stabilize regulation, improve transient response, and ensure ripple rejection performance. Omitting them may cause oscillation or degraded line/load regulation, especially under dynamic load changes or high-impedance source conditions.

What is the thermal resistance θ_JA of MC79L05CLP in its LP package?

The junction-to-ambient thermal resistance (θ_JA) of MC79L05CLP in the TO-92 (LP) package is 140°C/W. This value assumes standard PCB mounting with no added heatsinking. It determines the maximum power dissipation before thermal shutdown: at 25°C ambient, the device can safely dissipate approximately 0.36 W (i.e., (150°C − 25°C)/140°C/W). Derating is required at higher ambient temperatures.

Can MC79L05CLP be used in place of a Zener diode and resistor network?

Yes, MC79L05CLP is explicitly positioned as a direct replacement for Zener-diode/resistor combinations. It delivers two orders-of-magnitude lower output impedance, reduced bias current, and built-in thermal and short-circuit protection-improving regulation accuracy, efficiency, and reliability. Unlike discrete solutions, MC79L05CLP maintains consistent −5 V output across varying loads and temperatures without manual tuning.

What does the 'C' suffix in MC79L05CLP indicate?

The 'C' in MC79L05CLP denotes the output voltage tolerance grade: ±10% over the full operating temperature range (0°C to 125°C). This distinguishes it from the 'A' grade (±5%), which appears in part numbers like MC79L05ACLP. Both share identical pinout, package, and protection features-but the 'C' grade prioritizes cost and legacy compatibility over tight initial accuracy.