Texas Instruments MC79L15CDE4

Overview

MC79L15CDE4 from Texas Instruments is a fixed negative-voltage linear regulator delivering –15 V output at up to 100 mA, with ±10% output voltage tolerance, 1.7 V dropout at 40 mA, and internal thermal-overload and short-circuit protection. It operates across 0°C to 125°C and is used in on-card regulation for noise-sensitive analog subsystems in industrial control and instrumentation.

For engineers reviewing the MC79L15CDE4 datasheet, MC79L15CDE4 pinout, MC79L15CDE4 application, or MC79L15CDE4 equivalent, key selection criteria include input voltage range (–17.5 V to –30 V), output regulation (±1.5 V over 1–100 mA load), ripple rejection (33 dB at 120 Hz), bias current (6.5 mA typical), and TO-92-compatible LP package thermal performance (θ_JA = 140°C/W).

Technical Context

This device implements a monolithic PNP-series pass transistor architecture with built-in current limiting and thermal shutdown. Its feedback loop maintains regulated output without external components, relying on internal reference and error amplifier topology optimized for low-noise, low-quiescent-current operation.

It requires only 0.33 µF input and 0.1 µF output capacitors for stability. The regulator exhibits 90 µV RMS output noise (10 Hz–100 kHz) and maintains output voltage within ±1.5 V across full load (1–100 mA) and temperature (0°C–125°C), enabling direct replacement of Zener-resistor networks in precision analog rails.

Key Specifications

Pinout & Package

MC79L15CDE4 is packaged in the TO-226 (TO-92) plastic cylindrical LP package, with 3 leads and a thermal impedance of 140°C/W (θ_JA). Pin assignments are standardized per JEDEC TO-92 outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC79L15ACLP, the MC79L15CDE4 trades output accuracy for lower cost and broader tolerance acceptance; compared with LM7915ACZ, it offers smaller size and lower quiescent current but cannot support high-current or high-thermal-demand loads.

Availability

MC79L15CDE4 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, legacy analog instrumentation power, and embedded control board local regulation requiring stable component supply across extended production lifecycles.

Supply support for MC79L15CDE4 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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management ICs with broad industrial and automotive reach.

The MC79L00 series was designed specifically for cost-sensitive, low-power negative-voltage regulation in space-constrained analog subsystems-emphasizing simplicity, reliability, and compatibility with legacy discrete designs.

FAQ

What is the maximum input voltage rating for MC79L15CDE4?

The MC79L15CDE4 has an absolute maximum input voltage of –35 V, applicable for MC79L12 and MC79L15 variants. Operation above –30 V violates recommended conditions and risks permanent damage due to exceeding thermal limits or internal junction stress. Always maintain input within –17.5 V to –30 V for reliable function.

Does MC79L15CDE4 require external capacitors, and what values are specified?

Yes, MC79L15CDE4 requires a 0.33 µF capacitor across the input and a 0.1 µF capacitor across the output for stability and noise suppression. These values are validated in the datasheet for all operating conditions and must be placed close to the device pins to ensure proper transient response and ripple rejection.

What is the thermal performance of MC79L15CDE4 in its LP package?

The MC79L15CDE4 in the TO-92 (LP) package has a junction-to-ambient thermal resistance (θ_JA) of 140°C/W. At 100 mA output and 2 V dropout, power dissipation is ~200 mW, resulting in ~28°C junction rise above ambient-well within the 150°C maximum rating when ambient stays below 122°C.

How does MC79L15CDE4 compare to Zener-diode-based regulation?

MC79L15CDE4 provides two orders of magnitude lower output impedance than a typical Zener-resistor regulator, reduces bias current demand, and eliminates Zener voltage drift with temperature. It also integrates thermal and short-circuit protection-features absent in passive Zener solutions-making it more reliable in variable-load environments.

Is MC79L15CDE4 pin-compatible with other MC79Lxx devices?

Yes, all MC79Lxx devices-including MC79L15CDE4-share identical pinout (INPUT–COMMON–OUTPUT), package dimensions, and thermal characteristics in the LP package. This enables direct substitution across output voltages (e.g., –5 V, –12 V, –15 V) without PCB changes, provided input voltage and load requirements align.