Texas Instruments MC79L15CDG4

Overview

MC79L15CDG4 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 requires no external components for basic regulation in low-power analog or logic supply rails.

For engineers reviewing the MC79L15CDG4 datasheet, MC79L15CDG4 pinout, MC79L15CDG4 application, or MC79L15CDG4 equivalent, key selection criteria include input voltage range (–17.5 V to –30 V), output noise (90 µV RMS, 10 Hz–100 kHz), ripple rejection (33 dB at 120 Hz), bias current (6.5 mA at 25°C), and SOIC-8 package thermal impedance (97°C/W).

Technical Context

The MC79L15CDG4 implements a monolithic PNP series-pass transistor architecture with built-in current limiting and thermal shutdown circuitry. Its internal reference and error amplifier maintain stable –15 V output under varying load (1–100 mA) and line (–17.5 V to –30 V) conditions without external compensation.

Designed as a direct replacement for legacy MC79L15C variants, it uses standard three-terminal topology-Input, Output, Common-with no enable or adjustment pins. The SOIC-8 package (D package) supports surface-mount assembly and provides improved thermal performance over TO-92 alternatives.

Key Specifications

Pinout & Package

MC79L15CDG4 is housed in an 8-pin SOIC (D) package per JEDEC MS-012, with pins 1–3 and 6–8 unused (NC). Only pins 4 (Input), 5 (Output), and 7 (Common) are internally connected and functional.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC79L15ACD, MC79L15CDG4 trades voltage accuracy for cost and wider tolerance margin; compared with LM7915CD, it sacrifices current capacity and thermal performance for lower quiescent power and smaller footprint in space-constrained designs.

Availability

MC79L15CDG4 is available at Aetrix Electronics and suitable for industrial sensor interfaces, legacy instrumentation upgrades, and embedded analog peripheral power requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MC79L15CDG4 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 technologies since 1930.

The MC79L00 series was designed specifically for cost-sensitive, low-power negative-voltage regulation in industrial control, test equipment, and legacy system replacements where simplicity, reliability, and long-term availability are essential.

FAQ

What is the maximum input voltage rating for MC79L15CDG4?

The absolute maximum input voltage for MC79L15CDG4 is –30 V. Exceeding this value risks permanent device damage. For reliable operation, the recommended input range is –17.5 V to –30 V under all load and temperature conditions specified in the datasheet. This ensures proper regulation while respecting internal junction limits and thermal constraints inherent to the SOIC-8 package.

Does MC79L15CDG4 require external capacitors for stability?

Yes, MC79L15CDG4 requires a 0.33 µF capacitor between Input and Common, and a 0.1 µF capacitor between Output and Common, as specified in the TI SLVS011D datasheet. These values ensure phase margin and transient response meet design requirements. Omitting them may cause oscillation or poor load regulation, especially under dynamic current steps typical in sensor or microcontroller applications using MC79L15CDG4.

Is MC79L15CDG4 pin-compatible with TO-92 versions like MC79L15CLP?

No, MC79L15CDG4 is not pin-compatible with TO-92 packaged variants such as MC79L15CLP. While both share identical electrical functionality and terminal assignments (Input, Output, Common), the SOIC-8 (D) package has a different physical pinout and footprint. MC79L15CDG4 uses pins 4, 5, and 7 for connection; MC79L15CLP uses leads 1, 2, and 3 in a radial configuration. PCB layout must be redesigned for package interchange.

What is the typical output noise performance of MC79L15CDG4?

The typical output noise of MC79L15CDG4 is 90 µV RMS measured over a 10 Hz to 100 kHz bandwidth at 25°C. This value is confirmed in the electrical characteristics table for the MC79L15C grade under VI = –23 V and IO = 40 mA. Low noise is achieved through internal filtering and stable bandgap reference design, making MC79L15CDG4 suitable for powering precision analog circuits without additional post-regulation filtering.

Can MC79L15CDG4 be used in automotive applications?

MC79L15CDG4 is not qualified for automotive applications per AEC-Q100 standards. Its specified operating junction temperature range is 0°C to 125°C, which overlaps with some automotive ambient conditions, but it lacks automotive-grade qualification, extended temperature validation, or PPAP documentation. For automotive use, designers should select AEC-Q100 qualified alternatives such as TL79L15 or equivalent automotive-grade negative regulators instead of MC79L15CDG4.