Diodes Incorporated ZR78L057GTA

Overview

ZR78L057GTA from Zetex Semiconductors (now Diodes Incorporated) is a fixed-output +5.7 V positive linear voltage regulator in SOT223 package, designed for local point-of-load regulation with 200 mA output current capability, ±2.5% initial output tolerance, and internal thermal shutdown/short-circuit protection. It operates from 7.7 V to 20 V input, maintains regulation down to 7.4 V minimum input, and delivers stable output with no external components required.

For engineers reviewing the ZR78L057GTA datasheet, ZR78L057GTA pinout, ZR78L057GTA application, or ZR78L057GTA equivalent, key selection criteria include dropout voltage behavior across temperature, quiescent current stability at light loads, ripple rejection at 120 Hz, output noise (90 µV_rms), and thermal performance in SOT223 with 2 W power dissipation rating at 25°C ambient.

Technical Context

The ZR78L057GTA employs a monolithic bipolar architecture with internal current limiting and thermal foldback, enabling robust operation under overload and fault conditions without external protection circuitry. Its feedback loop is internally compensated, eliminating need for output capacitance stabilization.

It features a fixed 5.7 V reference derived from bandgap circuitry, with output voltage temperature coefficient of 0.15 mV/°C over −55°C to +125°C. Line regulation is specified at 10–40 mV across 7.7–20 V input range, and load regulation holds within 2.5–30 mV from 1 mA to 200 mA.

Key Specifications

Pinout & Package

SOT223 package (suffix G): 4-pin thermally enhanced surface-mount outline with exposed thermal pad (pin 4). Pin 4 is electrically isolated or connected to pin 2 (output) per layout requirements for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV757P57PDQNR and MCP1703T-5702E/MB, ZR78L057GTA offers superior fault resilience (integrated thermal/SC protection), higher output current margin (200 mA vs. 250 mA with derating), and proven ruggedness in industrial temperature cycling - making it optimal for cost-sensitive, reliability-critical embedded systems where board space permits SOT223.

Availability

ZR78L057GTA is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, medical portable diagnostics, and POS terminal peripheral interfaces requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for ZR78L057GTA 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 industrial, automotive, and communications markets.

ZR78L Series was engineered for rugged local regulation in space-constrained, thermally demanding applications - emphasizing intrinsic protection, wide temperature operation, and minimal external component count.

FAQ

What is the minimum input voltage required for ZR78L057GTA to maintain regulation at 200 mA?

The minimum input voltage is 7.4 V at 100 mA load per datasheet test condition; at 200 mA, the required input rises due to dropout voltage increase - typical dropout is ~1.7 V at 200 mA and 25°C, so Vin(min) ≈ 5.7 V + 1.7 V = 7.4 V. Derating is needed above 25°C ambient.

Can ZR78L057GTA be used without an output capacitor?

Yes - the device is internally compensated and stable with zero output capacitance. However, a 1–10 µF ceramic capacitor is recommended to improve transient response to load steps and reduce high-frequency noise coupling into downstream circuits.

Is pin 4 of the SOT223 package electrically connected or thermal-only?

Pin 4 is an exposed thermal pad with no internal electrical connection. It may be left floating or soldered to pin 2 (VOUT) or a dedicated thermal plane on the PCB to enhance heat dissipation - Diodes Inc. recommends connecting it to VOUT for best thermal performance.

How does ZR78L057GTA behave during thermal shutdown?

When junction temperature exceeds ~160°C, the device shuts down output and reduces quiescent current. Once junction temperature falls below ~140°C (typical hysteresis), regulation automatically resumes without external reset - enabling self-recovery in intermittent overload conditions.