Diodes Incorporated ZSR500N8TA

Overview

ZSR500N8TA from Zetex plc is a fixed-output 5.0 V positive voltage regulator in SO8 package, designed for local regulation in space-constrained PCBs. It delivers up to 200 mA output current with ±2.5% initial output voltage tolerance (4.875–5.125 V), 350 µA typical quiescent current, and operates across –55°C to +125°C. It is used in microcontroller power rails, sensor interface supplies, and industrial control modules where stability without external components is critical.

For engineers reviewing the ZSR500N8TA datasheet, ZSR500N8TA pinout, ZSR500N8TA application, or ZSR500N8TA equivalent, key selection criteria include dropout behavior under load transients, thermal performance in SO8 layout, ripple rejection at 120 Hz, and compatibility with input capacitors ≥1 µF for shutdown transient suppression.

Technical Context

The ZSR500N8TA employs an internally compensated series pass architecture with integrated thermal shutdown and short-circuit current limiting. Its regulation loop maintains output voltage within ±25 mV load regulation (1–200 mA) and ±40 mV line regulation (7–20 V input), enabling stable operation across wide input and load variations.

No external compensation components are required - stability is guaranteed over full temperature and load range due to internal frequency compensation and low output impedance (<0.1 Ω at 1 kHz). The device achieves 48–62 dB ripple rejection at 120 Hz with 200 mV_p-p input ripple, supporting noisy supply environments.

Key Specifications

Pinout & Package

SO8 surface-mount package (suffix N8), thermally enhanced with exposed pad (pin 4), rated for 780 mW at 25°C ambient on 2-inch² PCB. Pin 4 may be connected 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 MC78L05ACDR2G, the ZSR500N8TA uniquely combines zero-output-capacitor stability, integrated thermal protection, and 350 µA quiescent current - making it optimal for ruggedized, capacitor-minimized, and thermally constrained 5 V local regulation.

Availability

ZSR500N8TA is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical front-end sensors, and smart energy meter designs requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for ZSR500N8TA 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 plc (now part of Diodes Incorporated) is a UK-based semiconductor company specializing in high-performance analog and power management ICs for industrial, automotive, and communications markets.

The ZSR Series was developed specifically for local voltage regulation in harsh environments, emphasizing thermal resilience, no-external-component stability, and wide-temperature operation - addressing limitations of legacy 78Lxx regulators.

FAQ

Does ZSR500N8TA require an input capacitor?

Yes - a minimum 1 µF ceramic capacitor between IN and GND is required to prevent input voltage overshoot during thermal shutdown events caused by inductive source transients. This ensures the 20 V absolute maximum input rating is never exceeded, as specified in Issue 3, Section 4.

Can ZSR500N8TA operate without an output capacitor?

Yes - the device is unconditionally stable with zero output capacitance across its full operating range (–55°C to +125°C, 1–200 mA), confirmed by internal compensation and SO8 package parasitics. Output caps may be added for improved transient response but are not required for stability.

What is the maximum power dissipation for ZSR500N8TA at 85°C ambient?

At 85°C ambient, the SO8 package's 780 mW rating at 25°C is linearly derated to 468 mW (780 mW × [1 − (85−25)/100]). With 5 V output and 7 V minimum input, max sustainable current is ~234 mA before thermal shutdown activates - well above the 200 mA rated limit.

Is pin 4 (EPAD) electrically connected internally?

No - pin 4 is an exposed thermal pad with no internal electrical connection. Per Zetex documentation (Issue 3, p.15), it may be connected to PCB ground for thermal performance or left floating; it serves solely as a heatsink path, not a functional terminal.