onsemi MC78L09ACDR2

Overview

MC78L09ACDR2 from onsemi is a 100 mA, fixed +9.0 V positive linear voltage regulator in SOIC-8 package with internal short-circuit and thermal overload protection. It operates over 0°C to +125°C junction temperature, requires no external components for basic regulation, and delivers stable output with ≤15 mV load regulation (1–40 mA) and 37–57 dB ripple rejection at 120 Hz.

For engineers reviewing the MC78L09ACDR2 datasheet, pinout, applications, or equivalent options, key selection criteria include dropout voltage (1.7 V typical), input bias current (3.0–6.0 mA), thermal resistance (R_JA per PCB copper area), and compatibility with standard SOIC-8 footprints in industrial power management designs.

Technical Context

This device implements a monolithic series-pass linear regulator architecture with built-in current limiting and thermal shutdown. Its internal circuitry includes a precision reference, error amplifier, and Darlington pass transistor-enabling stable regulation without external compensation under typical loads.

It is designed for use with input voltages from 11.5 V to 24 V DC, maintaining regulation as long as input remains ≥2.0 V above output (i.e., ≥11.0 V minimum). Output noise is 60 µV_RMS (10 Hz–100 kHz), and line regulation is specified at 20 mV max over full input range.

Key Specifications

Pinout & Package

MC78L09ACDR2 is housed in an SOIC-8 (Case 751, D Suffix) package with exposed die attach flag connected internally to pins 2, 3, 6, and 7 (all GND). Thermal resistance depends on PCB copper area per Figure 8.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC78L09ACDR2, MC78L09ACPG trades thermal efficiency for through-hole flexibility, while LM78L09ACM/NOPB offers functional equivalence with minor quiescent current variance-both require validation of thermal margin and long-term availability before design-in.

Availability

MC78L09ACDR2 is available at Aetrix Electronics and suitable for industrial sensor power supplies, embedded microcontroller core rails, legacy equipment voltage translation, and low-power analog signal chains requiring stable component supply and RoHS-compliant packaging.

Supply support for MC78L09ACDR2 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 manufacturer specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The MC78L00A Series was engineered as a cost-effective, rugged replacement for zener-diode-based regulation in low-current industrial and consumer systems-emphasizing simplicity, reliability, and wide operating temperature tolerance without external components.

FAQ

What is the maximum input voltage rating for MC78L09ACDR2?

The absolute maximum input voltage for MC78L09ACDR2 is 35 V DC for 12–18 V nominal output variants. This rating ensures safe operation during transient surges or unregulated supply variations while maintaining internal protection integrity. Exceeding 35 V risks permanent damage even with brief exposure, as confirmed in the Absolute Maximum Ratings table on page 2 of the datasheet.

Does MC78L09ACDR2 require input and output capacitors for stability?

MC78L09ACDR2 does not require output capacitance for stability, but a 0.1 µF ceramic capacitor is recommended to improve transient response. An input bypass capacitor (≥0.33 µF tantalum or low-ESR ceramic) is required if the regulator is located >5 cm from the main power filter or drives large capacitive loads. These values are specified in Figure 2 and Applications Information section on page 8.

What is the thermal resistance (R_JA) of MC78L09ACDR2 in SOIC-8 package?

MC78L09ACDR2 has no fixed R_JA; its junction-to-ambient thermal resistance varies with PCB copper area per Figure 8. With 1 in² (645 mm²) of 2 oz. copper, R_JA is ~70°C/W. Without added copper, it approaches 160°C/W. The SOIC-8's internal lead-frame modification (pins 2/3/6/7 tied to die flag) enables this scalable thermal performance-unlike TO-92's fixed 200°C/W.

Can MC78L09ACDR2 be used as a current source?

Yes, MC78L09ACDR2 can be configured as a constant-current sink or source using external resistors per Figure 9. For example, connecting a resistor between VOUT and load to ground yields I_OUT ≈ 9.0 V / R. However, power dissipation must stay within thermal limits: at 100 mA and 12 V input, dropout power is (12 − 9) × 0.1 = 0.3 W-requiring adequate PCB copper for SOIC-8.

Is MC78L09ACDR2 qualified for automotive applications?

No, MC78L09ACDR2 is rated for 0°C to +125°C junction temperature and is not AEC-Q100 qualified. For automotive use, select NCV78L09ABDR2G (−40°C to +125°C, AEC-Q100 Grade 1, PPAP-capable) instead. The "C" suffix denotes commercial temperature grade, while "B" indicates extended automotive range-confirmed in Ordering Information tables on pages 9–10.