Diodes Incorporated ZR78L05GTA

Overview

ZR78L05GTA from Zetex Semiconductors (now Diodes Incorporated) is a fixed +5.0 V, 200 mA positive voltage regulator in SOT223 package with internal current limiting and thermal shutdown. It maintains output voltage within ±2.5% initial tolerance, delivers 75 µV_rms output noise (10 Hz–10 kHz), and operates across –55°C to +125°C ambient. Designed for local regulation in space-constrained embedded systems, it eliminates need for external compensation components.

For engineers reviewing the ZR78L05GTA datasheet, ZR78L05GTA pinout, ZR78L05GTA application, or ZR78L05GTA equivalent, key selection criteria include dropout voltage (≤2.0 V at 200 mA), quiescent current (350 µA typ.), ripple rejection (48–62 dB at 120 Hz), thermal shutdown behavior, and compatibility with low-ESR ceramic output capacitors in compact PCB layouts.

Technical Context

The ZR78L05GTA employs a monolithic bipolar linear regulator architecture with built-in short-circuit current limiting and foldback protection. Its thermal shutdown activates above junction temperature thresholds and automatically recovers upon cooling-no latch-up or manual reset required.

It achieves stable regulation without external capacitors due to internal frequency compensation and exhibits low load/line regulation (≤25 mV and ≤40 mV respectively) over full input range (7–20 V) and output current (1–200 mA). Output voltage drift is tightly controlled at 0.1 mV/°C over –55°C to +125°C.

Key Specifications

Pinout & Package

SOT223 package (suffix G), 4-pin thermally enhanced surface-mount outline with exposed thermal pad (pin 4). Pin 4 is internally connected to the die substrate and may be tied to ground or left floating per layout requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV70550DBVR and MCP1700T-5002E/TT, ZR78L05GTA uniquely supports wide-input (7–20 V), integrates self-recovering thermal protection, and delivers best-in-class noise performance for analog-sensitive designs-without requiring additional support circuitry.

Availability

ZR78L05GTA is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, medical wearables, and point-of-sale peripheral controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ZR78L05GTA 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

Zetex Semiconductors, acquired by Diodes Incorporated in 2008, specialized in high-performance analog and discrete semiconductors for demanding industrial and automotive applications.

The ZR78L Series was designed specifically for rugged local voltage regulation in space-constrained, thermally challenging environments-emphasizing fault resilience, wide temperature operation, and minimal external component count.

FAQ

What is the minimum input voltage required for ZR78L05GTA to regulate at full 200 mA load?

The minimum input voltage is 6.7 V at 25°C ambient, as specified in the "Input Voltage Required To Maintain Regulation" parameter (typ. 7.0 V, min. 6.7 V). Below this, output voltage drops out of regulation. At elevated temperatures or higher PCB thermal resistance, derating applies-consult thermal resistance curves in the datasheet.

Can ZR78L05GTA be used with ceramic output capacitors?

Yes-ZR78L05GTA is fully stable with ceramic output capacitors ranging from 0.1 µF to 10 µF. Unlike older regulators, it does not require ESR-based damping; its internal compensation ensures phase margin >60° across all recommended capacitor values and ESRs down to 10 mΩ.

Does pin 4 (thermal tab) need to be connected to ground?

No-pin 4 is the exposed thermal pad connected to the silicon substrate (collector of the pass transistor). It may be left electrically floating or connected to ground depending on PCB layout and thermal goals. If grounded, ensure adequate isolation from other signals; if unconnected, maximize solder mask opening and copper pour for heat spreading.

How does thermal shutdown behave during sustained overload?

Under sustained overload, ZR78L05GTA enters thermal shutdown when junction temperature exceeds ~150°C, dropping output to near zero. As the die cools (via PCB conduction/convection), regulation automatically resumes-no external reset or power cycle is needed. This hiccup-mode behavior prevents permanent damage while maintaining system recoverability.