Diodes Incorporated ZR78L08GTA

Overview

ZR78L08GTA from Zetex Semiconductors (now Diodes Incorporated) is a fixed-output 8.0 V positive linear voltage regulator in SOT223 package, designed for local regulation in space-constrained PCBs. It delivers up to 200 mA output current with ±2.5% initial output voltage tolerance, 350 µA typical quiescent current, and operates across –55°C to +125°C ambient. Used in industrial sensor nodes and microcontroller power rails where low-noise, self-contained regulation is required.

For engineers reviewing the ZR78L08GTA datasheet, ZR78L08GTA pinout, ZR78L08GTA application, or ZR78L08GTA equivalent, this page provides verified electrical specs, thermal behavior, load/line regulation performance, dropout characteristics, and real-world design guidance - all confirmed from the official ZR78L Series datasheet (Issue 3, December 2001).

Technical Context

The ZR78L08GTA employs a monolithic bipolar architecture with internal current limiting and thermal shutdown circuitry, enabling robust operation without external protection components. Its output voltage is trimmed at wafer level to maintain 7.8 V to 8.2 V over 1–200 mA load and input voltages from 10 V to 20 V.

It achieves 44 dB ripple rejection at 120 Hz (Vin = 11–18 V), exhibits 115 µV_rms output noise (10 Hz–10 kHz), and maintains stable regulation with no external capacitors - validated across temperature and transient conditions including line/load transients up to 5 V/µs and 1 A/µs.

Key Specifications

Pinout & Package

SOT223 package (suffix 'G') with 4-pin configuration: Pin 1 = Input, Pin 2 = Ground, Pin 3 = Output, Pin 4 = Thermal pad (internally connected to ground or left floating per layout). Thermal pad enhances heat dissipation; recommended PCB copper area ≥ 2 in² for full 2 W rating at 25°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV76780DBVR and LD1086S80TR, ZR78L08GTA offers optimal balance of legacy footprint compatibility, zero-external-component operation, and proven ruggedness in harsh thermal environments - making it ideal for cost-sensitive, long-lifecycle industrial and automotive modules where design reuse and reliability outweigh marginal efficiency gains.

Availability

ZR78L08GTA is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body electronics, programmable logic controller I/O modules, and medical auxiliary power rails requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for ZR78L08GTA 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-reliability analog and discrete semiconductors for industrial, automotive, and aerospace markets.

The ZR78L Series was engineered specifically for local voltage regulation in thermally demanding, space-constrained applications - emphasizing intrinsic fault tolerance, wide temperature operation, and minimal external component count.

FAQ

Is ZR78L08GTA stable without an output capacitor?

Yes. The ZR78L08GTA is internally compensated and fully stable with no output capacitor required - confirmed in the official datasheet under "No external components" feature and transient response plots. However, adding a 1–10 µF ceramic capacitor at the output improves load transient response and reduces high-frequency noise.

What is the maximum power dissipation for ZR78L08GTA in SOT223?

At 25°C ambient, the SOT223 package supports up to 2 W maximum power dissipation (per Note 3 in Absolute Maximum Ratings). This derates linearly to zero at 125°C ambient, yielding ~1.2 W usable at 75°C ambient - sufficient for 200 mA output with 2 V dropout (i.e., 8 V × 0.2 A = 1.6 W load + ~0.4 W dissipation).

Can ZR78L08GTA be used with input voltages below 10 V?

No. The datasheet specifies a minimum input voltage of 10 V to maintain regulation at full load (200 mA). At lower inputs, output voltage collapses - e.g., at Vin = 9.7 V, regulation fails per test condition tables. For 8 V output with lower input headroom, a low-dropout (LDO) regulator is required instead.

Does pin 4 (EPAD) require connection in the ZR78L08GTA SOT223 package?

Pin 4 is a thermal pad, not an electrical signal. It may be left electrically floating but must be soldered to a PCB copper pour for thermal performance. Best practice is to connect it to ground via multiple vias - this lowers thermal resistance and improves current capability, especially above 100 mA or in high-ambient environments.