Diodes Incorporated ZX5T851ZTA

Overview

ZX5T851ZTA from Zetex Semiconductors is a 60V NPN medium-power transistor in SOT89 package, designed for low-loss switching in DC-DC converters and power management circuits. It delivers 5A continuous collector current, 30mΩ equivalent on-resistance at 6A, and V_CE(SAT) as low as 17mV at 100mA/5mA drive-enabling high-efficiency motor drivers and solenoid control.

For engineers reviewing the ZX5T851ZTA datasheet, ZX5T851ZTA pinout, ZX5T851ZTA application, or ZX5T851ZTA equivalent, key selection criteria include verified V_CE(SAT) performance at 6A, thermal resistance (R_JA = 60°C/W on 50mm×50mm PCB), h_FE ≥100 at 5A, and SOT89 thermal pad compatibility with industrial power-stage layouts.

Technical Context

This NPN bipolar junction transistor uses 5th-generation low-saturation process technology to minimize conduction losses while maintaining robust safe operating area (SOA) up to 20A peak pulse current. Its BVCBO of 150V and BVCEO of 60V support operation in 48V bus systems with margin.

The device exhibits strong DC current gain linearity: h_FE = 200 at IC = 2A, 105 at IC = 5A, and 40 at IC = 10A under V_CE = 1V-enabling predictable base drive design across load ranges without active compensation.

Key Specifications

Pinout & Package

Package: SOT89 - surface-mount plastic package with exposed thermal pad (E1 = 2.60 mm max), optimized for PCB heat spreading on single-sided 1oz copper.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN medium-power switching applications.

Compared with MJD122G, ZX5T851ZTA reduces conduction loss by >98% at 100mA and enables 3× higher power density in DC-DC modules due to superior thermal resistance and saturation voltage.

Availability

ZX5T851ZTA is available at Aetrix Electronics and suitable for emergency lighting circuits, DC fan motor drivers, and solenoid actuator interfaces requiring stable component supply across industrial production cycles.

Supply support for ZX5T851ZTA 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 (now part of Diodes Incorporated) specialized in high-performance analog and discrete semiconductors, with focus on efficiency-critical power devices.

The ZX5T series targets medium-power switching applications where low V_CE(SAT), high h_FE, and thermal reliability are essential-especially in space-constrained DC-DC, motor, and actuator control modules.

FAQ

What is the maximum continuous collector current for ZX5T851ZTA?

The ZX5T851ZTA supports 5A continuous collector current at T_A = 25°C with proper PCB thermal management (50mm × 50mm, 1oz copper). Derating begins at 16.8 mW/°C above 25°C, limiting usable current to ~3.2A at 85°C ambient.

Does ZX5T851ZTA require a heatsink in typical applications?

No external heatsink is required when mounted on a 50mm × 50mm FR4 PCB with high-coverage 1oz copper, achieving R_JA = 60°C/W. At 2.1W dissipation (PD max), junction temperature stays within -55°C to +150°C range without added thermal mass.

Can ZX5T851ZTA replace a MOSFET in gate driver circuits?

Yes-it is explicitly qualified as a MOSFET gate driver (per datasheet Applications section). Its 300mA base drive capability, 760ns t_OFF, and low V_CE(SAT) enable efficient charging/discharging of gate capacitance in high-side or low-side configurations up to 1MHz.

What is the meaning of "RSAT = 30m" in the product summary?

"RSAT = 30m" refers to the equivalent on-state resistance of 30 mΩ, derived from V_CE(SAT)/I_C at I_C = 6A and I_B = 300mA. This metric quantifies conduction loss like a MOSFET's R_DS(on), confirming suitability for high-efficiency linear and switching applications.