Diodes Incorporated AZ78L05RTR-G1

Overview

AZ78L05RTR-G1 from BCD Semiconductor Manufacturing Limited is a fixed-output +5 V, 100 mA three-terminal positive linear regulator in SOT-89 package, featuring ±5% output voltage tolerance over −40°C to +125°C, internal short-circuit current limiting, and thermal shutdown protection. It delivers stable local regulation for microprocessor I/O rails and post-regulation of switching supplies with 1.6 V dropout and 40 μV RMS output noise.

For engineers reviewing the AZ78L05RTR-G1 datasheet, AZ78L05RTR-G1 pinout, AZ78L05RTR-G1 application, or AZ78L05RTR-G1 equivalent, this device is selected for low-quiescent-current (3–5 mA), high-PSRR (47–62 dB at 120 Hz), and thermally robust (θ_JC = 29.8°C/W) DC/DC post-regulation in space-constrained industrial control and embedded systems.

Technical Context

The AZ78L05RTR-G1 implements a monolithic series-pass linear regulator architecture with built-in bandgap reference, error amplifier, and Darlington pass transistor. Its thermal shutdown activates when junction temperature exceeds 150°C, and current limit caps peak output at 150 mA regardless of load or input conditions.

It requires no external compensation components and operates with only 0.33 μF input and 0.1 μF output ceramic capacitors. The SOT-89 package provides 29.8°C/W junction-to-case thermal resistance, enabling 100 mA continuous output at ambient temperatures up to +85°C with minimal heatsinking.

Key Specifications

Pinout & Package

SOT-89 package: 3-pin surface-mount plastic package with exposed thermal pad (pin 2 connected to GND for optimal heat transfer). Dimensions: 4.4 × 2.6 × 1.6 mm (L × W × H).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL78L05ACDR and MCP1700T-5002E/MB, the AZ78L05RTR-G1 uniquely balances 100 mA capability, 29.8°C/W thermal resistance, and 5 V ±5% accuracy in a manufacturable SOT-89 package-making it optimal for cost-sensitive, thermally demanding 5 V post-regulation tasks.

Availability

AZ78L05RTR-G1 is available at Aetrix Electronics and suitable for industrial sensor interfaces, microprocessor I/O power supplies, and HiFi audio signal chains requiring stable component supply, RoHS-compliant green packaging, and tape-and-reel delivery for automated assembly.

Supply support for AZ78L05RTR-G1 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

BCD Semiconductor Manufacturing Limited is a Shanghai-based fabless analog IC designer specializing in high-reliability power management, LED drivers, and linear regulators for industrial and consumer markets.

The AZ78LXX series was developed to replace discrete Zener-resistor regulators in cost-sensitive, space-constrained applications-delivering improved regulation accuracy, thermal safety, and ease of integration without external components.

FAQ

What is the minimum input voltage required for regulation at full 100 mA load?

The AZ78L05RTR-G1 requires a minimum input voltage of 6.7 V to maintain regulated 5 V output at 100 mA load, based on its 1.6 V dropout specification and output tolerance. Below this, output voltage collapses linearly with input; operation below 6.7 V is outside recommended conditions and risks unregulated behavior.

Can the AZ78L05RTR-G1 be used without input or output capacitors?

No. The datasheet mandates a minimum 0.33 μF input capacitor and 0.1 μF output capacitor for stability and transient response. Omitting either causes oscillation or excessive output voltage overshoot during load steps, as confirmed by Figures 8 and 9 in the datasheet. Ceramic X7R types are recommended.

Does the SOT-89 package require PCB copper pour for thermal performance?

Yes. The exposed tab (pin 2) must be soldered to a ≥100 mm² copper pour connected to GND for effective heat dissipation. Without this, junction temperature rises rapidly above ambient-derating to ≤60 mA at +70°C ambient. Thermal resistance degrades from 29.8°C/W to >60°C/W without proper copper area.

How does thermal shutdown behave during sustained overload?

When internal power dissipation raises junction temperature beyond ~150°C, the thermal shutdown circuit disables the pass transistor until temperature falls by ~15°C, then re-enables. This hiccup-mode cycling prevents permanent damage but causes output voltage interruption-intended only as fault protection, not continuous operation.