Diodes Incorporated ZX5T849ZTA

Overview

ZX5T849ZTA from Zetex Semiconductors is a 30V NPN medium-power transistor in SOT89 package, featuring BV_CEO = 30 V, R_SAT = 23 mΩ at I_C = 6.5 A, and continuous I_C = 6 A. It delivers ultra-low saturation voltage (V_CE(SAT) = 25 mV typ. at 1 A/100 mA), high h_FE (100–300), and f_T = 140 MHz - optimized for DC-DC converter switching stages and MOSFET gate drive circuits.

For engineers reviewing the ZX5T849ZTA datasheet, ZX5T849ZTA pinout, ZX5T849ZTA application, or ZX5T849ZTA equivalent, key selection criteria include verified low R_SAT, thermal performance on 50 mm × 50 mm PCB (R_JA = 60 °C/W), peak I_CM = 20 A capability, and SOT89 thermal pad compatibility with industrial power management layouts.

Technical Context

This NPN bipolar transistor employs 5th-generation low-saturation process technology to minimize conduction losses in medium-current switching applications. Its BVCBO = 80 V and BVCEO = 30 V define safe operating limits for 24 V system rails, while h_FE stability up to 20 A enables robust current gain in pulsed motor control and charging circuitry.

The device operates with V_BE(SAT) = 1.1 V at 6.5 A/300 mA drive, supporting efficient base drive design. Switching times (t_ON = 37 ns, t_OFF = 425 ns) and f_T = 140 MHz confirm suitability for high-frequency DC-DC topologies up to ~500 kHz without excessive switching loss penalties.

Key Specifications

Pinout & Package

Package: SOT89 - surface-mount plastic package with exposed thermal pad (E-pad), 3-terminal outline (Emitter, Base, Collector), footprint per JEDEC TO-243AA. Designed for high thermal conductivity on PCB copper pours.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZXTN25012E6TA and MJD122G, ZX5T849ZTA uniquely balances low R_SAT, SOT89 thermal performance, and 30 V system compatibility - making it optimal for compact, high-efficiency 24 V power conversion where board area and thermal resistance are critical constraints.

Availability

ZX5T849ZTA is available at Aetrix Electronics and suitable for DC-DC converters, MOSFET gate drivers, and industrial power switches requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.

Supply support for ZX5T849ZTA 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 engineering centers in UK, Germany, and US.

ZX5T849ZTA belongs to Zetex's 5th-generation low-saturation NPN transistor family, designed specifically for high-efficiency, medium-current power switching in space-constrained industrial and telecom power systems.

FAQ

What is the maximum allowable junction temperature for ZX5T849ZTA?

The absolute maximum junction temperature is +150 °C, and the storage temperature range matches this limit. Operation above 125 °C requires derating of power dissipation per the linear derating factor (16.8 mW/°C for 50 mm × 50 mm PCB layout), and thermal design must ensure T_J remains within spec under worst-case ambient and load conditions.

Can ZX5T849ZTA replace a MOSFET in low-side switching applications?

ZX5T849ZTA is not a direct MOSFET replacement due to its bipolar drive requirement and lack of inherent body diode. However, it excels as a low-R_SAT alternative in applications where gate drive complexity, cost, or thermal constraints favor bipolar solutions - especially where base drive current is readily available and switching frequencies remain below 500 kHz.

Is the SOT89 thermal pad electrically isolated?

No - the exposed thermal pad on the ZX5T849ZTA SOT89 package is internally connected to the emitter terminal. PCB layout must tie the pad directly to the emitter net and use multiple thermal vias to inner-layer ground or emitter copper pour to maximize heat transfer without creating unintended shorts.

What is the recommended base resistor value for 6.5 A collector current?

With V_BE(SAT) ≈ 1.1 V and required I_B = 300 mA (per datasheet test condition), a 10 Ω ±5% resistor is typical when driven from a 4.5 V logic source (e.g., 3.3 V MCU with level-shifter). Layout must minimize base trace inductance, and a 100 nF ceramic capacitor should be placed near the base pin to suppress ringing during fast switching transitions.