onsemi MC79L05ACD

Overview

MC79L05ACD from onsemi is a three-terminal, fixed-output, negative-voltage linear regulator delivering −5.0 V at up to 100 mA, featuring internal thermal shutdown and short-circuit current limiting in an SOIC-8 package. It operates across 0 °C to +125 °C junction temperature, requires no external components for basic operation, and is used for on-card negative rail regulation in analog signal chains and mixed-signal subsystems.

For engineers reviewing the MC79L05ACD datasheet, pinout, applications, or equivalent options, key selection criteria include its −5.0 V output tolerance (±4%), dropout voltage of 1.7 V at 40 mA, 41–49 dB ripple rejection at 120 Hz, input voltage range up to −30 V, and SOIC-8 thermal resistance (R_JA = 180 °C/W).

Technical Context

The MC79L05ACD implements a monolithic bipolar linear regulator architecture with built-in current-limiting and thermal-foldback protection. Its internal circuitry includes error amplifier, reference, pass transistor, and protection logic - all integrated without external compensation requirements under standard conditions.

It is designed for fixed negative output regulation where input-to-output differential remains ≥1.7 V, supports capacitor-stabilized operation with 0.33 μF input and 0.1 μF output bypass, and maintains regulation over load currents from 1.0 mA to 100 mA and input voltages from −7.0 V to −30 V.

Key Specifications

Pinout & Package

MC79L05ACD is housed in a Pb-free SOIC-8 (Case 751) surface-mount package measuring 4.9 × 3.9 × 1.5 mm. Pin 1 is Ground, Pins 2 and 3 are Input (Vin), Pin 4 is No Connect, Pin 5 is Ground, Pins 6 and 7 are Input (Vin), and Pin 8 is No Connect - per onsemi's official marking diagram and ordering information.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM79L05ACM/NOPB, MC79L05ACD delivers superior ripple rejection and lower dropout; compared with MC79L05ABDR2G, it trades extended temperature capability for lower cost and qualification overhead in commercial-grade applications.

Availability

MC79L05ACD is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, legacy RS-232 transceiver bias, and low-power analog data acquisition requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MC79L05ACD 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, and sensing solutions for automotive, industrial, and cloud infrastructure markets.

The MC79L00A Series - including MC79L05ACD - was engineered for cost-sensitive, low-current negative voltage regulation in embedded analog subsystems, emphasizing ruggedness, simplicity, and compatibility with complementary MC78L00 positive regulators.

FAQ

What is the maximum input voltage for MC79L05ACD?

The MC79L05ACD supports a maximum input voltage of −30 V DC when configured for −5 V output. This rating applies at TA = +25 °C and assumes proper thermal management. Exceeding −30 V risks permanent damage due to junction breakdown, as specified in the Absolute Maximum Ratings table of the onsemi datasheet.

Does MC79L05ACD require input and output capacitors?

MC79L05ACD does not require external capacitors for basic regulation, but onsemi recommends a 0.33 μF input bypass capacitor (tantalum or ceramic) and a 0.1 μF output capacitor for stability - especially with long input traces or large output capacitance. These values minimize oscillation and improve transient response in real-world PCB layouts.

What is the thermal resistance of MC79L05ACD in SOIC-8 package?

The MC79L05ACD in SOIC-8 (Case 751) has a junction-to-ambient thermal resistance (R_JA) of 180 °C/W at TA = +25 °C with minimum recommended copper pad area. Its junction-to-case resistance (R_JC) is 45 °C/W. These values assume standard JEDEC 2-layer board layout; actual R_JA improves with larger copper areas per Figure 9 in the datasheet.

Is MC79L05ACD pin-compatible with TO-92 versions like MC79L05ACPG?

No - MC79L05ACD (SOIC-8) and MC79L05ACPG (TO-92) have fundamentally different pinouts and terminal counts. The SOIC-8 version uses 8 pins with multiple Vin and GND connections plus NCs, while TO-92 uses 3 pins (GND, Input, Output). Direct PCB replacement is not possible without layout redesign.

What is the output voltage tolerance of MC79L05ACD over temperature?

The MC79L05ACD guarantees an output voltage of −4.75 V to −5.25 V (±5%) across its full operating temperature range of 0 °C to +125 °C, as verified under VI = −10 V and IO = 1–40 mA conditions. At +25 °C, tighter tolerance of −4.8 V to −5.2 V (±4%) applies per Electrical Characteristics table.