Diodes Incorporated ZXTBM322TA

Overview

ZXTBM322TA from Diodes Incorporated (formerly Zetex) is a 20V NPN low-saturation transistor in a 2mm × 2mm MLP package, delivering V_CE(sat) = 90 mV @ I_C = 1 A, I_C = 4.5 A continuous, and h_FE = 300 @ I_C = 10 mA. It serves as a high-efficiency power switch in DC–DC converter FET drivers and LED backlighting circuits where minimal conduction loss and compact board area are critical.

For engineers reviewing the ZXTBM322TA datasheet, ZXTBM322TA pinout, ZXTBM322TA application, or ZXTBM322TA equivalent, key selection criteria include verified V_CE(sat) performance at ≥2 A, thermal resistance under real PCB copper conditions (R_θJA = 42 °C/W with 65 cm² 2 oz Cu), and MLP package solderability with exposed thermal pad alignment.

Technical Context

This device employs a fourth-generation epitaxial planar structure optimized for low V_CE(sat) and high h_FE linearity up to 6 A. Its saturation voltage remains ≤210 mV at I_C = 4.5 A / I_B = 125 mA, enabling efficient switching in synchronous rectifier and gate-drive stages.

The 2mm × 2mm MLP package integrates an exposed thermal pad tied to the collector, supporting R_θJA as low as 42 °C/W when mounted on 65 cm² of 2 oz copper-critical for thermally constrained DC–DC modules operating near 150 °C junction temperature.

Key Specifications

Pinout & Package

Package: 2mm × 2mm MLP (Micro Leaded Package), 3-pin single-die outline with exposed collector pad on underside. Nominal height 0.9 mm; thermal pad must be soldered to PCB copper for rated R_θJA.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN low-saturation transistor applications.

Compared with ZXTN618MA and DMT3006LPSQ-7, ZXTBM322TA delivers superior thermal efficiency and higher current capability in the same footprint-making it optimal for high-density, high-efficiency DC–DC and motor drive applications demanding ≤90 mV saturation voltage.

Availability

ZXTBM322TA is available at Aetrix Electronics and suitable for DC–DC converters, LED backlighting systems, and brushed DC motor control requiring stable component supply and long-term production continuity.

Supply support for ZXTBM322TA 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

Diodes Incorporated acquired Zetex plc in 2008 and continues its legacy of high-performance discrete semiconductors for power management and signal conditioning.

The ZXT series targets high-efficiency, space-constrained power switching applications-specifically engineered for low V_CE(sat), high h_FE, and thermally robust MLP packaging in portable and industrial power systems.

FAQ

What is the maximum allowable PCB copper area to achieve the lowest R_θJA specification?

The 42 °C/W R_θJA value requires 65 cm² of 2 oz copper on FR4. This area corresponds to a 10 cm × 6.5 cm thermal plane connected directly to the exposed collector pad. Smaller copper areas increase thermal resistance proportionally-e.g., 10 cm² yields R_θJA ≈ 125 °C/W per datasheet note (d).

Is the ZXTBM322TA pin-compatible with the obsolete ZXTN618MA?

Yes-both devices share identical 2mm × 2mm MLP pinout (Emitter–Collector–Base), same pad layout, and compatible solder reflow profiles. The ZXTN618MA was introduced as a direct replacement with adjusted h_FE and V_CE(sat) specs but no mechanical changes.

Can this transistor be used in linear regulator applications?

No-it is not characterized or rated for linear-mode operation. Absolute maximum ratings assume switching duty cycles ≤2%; sustained linear operation risks exceeding T_J(max) = 150 °C due to uncontrolled power dissipation and lack of Safe Operating Area (SOA) data beyond pulsed conditions.

Does the MLP package require special stencil design for assembly?

Yes-the exposed collector pad demands a windowed stencil opening (0.35 mm thickness, 1.8 mm × 1.8 mm aperture) and solder paste volume matching IPC-7525B Class III guidelines. Insufficient paste causes voiding; excess paste risks bridging to adjacent pins during reflow.