Diodes Incorporated AP78L12YG-13

Overview

AP78L12YG-13 from Diodes Incorporated is a fixed-output +12 V, 100 mA three-terminal positive linear voltage regulator in SOT89 package with ±5% output tolerance, thermal overload protection, and internal short-circuit current limiting. It delivers stable local regulation for logic supplies and consumer electronics where low quiescent current (3–5 mA) and dropout voltage ≤2.5 V at 40 mA are required.

For engineers reviewing the AP78L12YG-13 datasheet, AP78L12YG-13 pinout, AP78L12YG-13 application, or AP78L12YG-13 equivalent, key selection criteria include input voltage range (14.5–27 V), load regulation (≤100 mV over 1–100 mA), ripple rejection (40–54 dB at 120 Hz), and thermal resistance (θ_JA = 145 °C/W, θ_JC = 25 °C/W).

Technical Context

The AP78L12YG-13 implements a monolithic series pass transistor architecture with built-in safe-area protection that reduces short-circuit current as pass transistor voltage increases. Its internal bandgap reference and error amplifier maintain output regulation across –20°C to +125°C junction temperature.

Thermal shutdown activates at T_J = 150°C, and current limiting caps peak output at 140 mA. The device requires no external components for basic operation but specifies 0.33 µF input and 0.1 µF output capacitors for stability when located >3 inches from the power supply filter.

Key Specifications

Pinout & Package

AP78L12YG-13 is housed in a 3-pin SOT89 surface-mount package with exposed thermal pad. Pin 1 = VOUT, Pin 2 = GND, Pin 3 = VIN (top view). The package supports high thermal efficiency via direct PCB copper conduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L12ACZ and MC78L12CP, AP78L12YG-13 offers superior thermal efficiency in SOT89, guaranteed RoHS/Green compliance, and tighter output tolerance - making it optimal for space-constrained, thermally demanding, and environmentally regulated consumer electronics.

Availability

AP78L12YG-13 is available at Aetrix Electronics and suitable for CD-ROM drives, DVD players, set-top boxes, and industrial I/O modules requiring stable component supply, RoHS compliance, and SMT-compatible packaging.

Supply support for AP78L12YG-13 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The AP78LXX series was designed for cost-sensitive, space-constrained applications requiring simple, robust local regulation - targeting consumer audio/video equipment, optical storage, and embedded control systems.

FAQ

What is the minimum input voltage required for AP78L12YG-13 to maintain regulation?

The AP78L12YG-13 requires a minimum input voltage of 13.7 V to maintain line regulation under all conditions, with 14.5 V specified as the recommended minimum for full 100 mA output capability. Below this threshold, output voltage drops nonlinearly due to insufficient headroom across the pass transistor.

Can AP78L12YG-13 operate without input and output capacitors?

No - the datasheet mandates a 0.33 µF input capacitor if the regulator is placed more than 3 inches from the main power supply filter, and a 0.1 µF output capacitor for high-frequency stability. Omitting either risks oscillation, poor transient response, or failure to meet ripple rejection specifications.

How does the safe-area protection function during a short-circuit event?

During a short-circuit, the AP78L12YG-13's safe-area protection reduces output current as the voltage across the pass transistor increases, preventing simultaneous high voltage and high current stress. This limits internal power dissipation and avoids second breakdown, enabling reliable recovery after fault removal.

Is AP78L12YG-13 compatible with lead-free reflow profiles?

Yes - the SOT89 package uses lead-free terminations and green (Br/Sb-free) molding compound, qualified for standard JEDEC J-STD-020D reflow profiles with peak temperatures up to 260°C. The device meets IPC/JEDEC classifications for moisture sensitivity level (MSL) 1.