Diodes Incorporated ZXTN5551GTA

Overview

ZXTN5551GTA from Diodes Incorporated is a high-voltage NPN bipolar junction transistor rated for 160V V_CEO, 600mA continuous collector current, and 2W power dissipation in SOT223 package; it delivers low saturation voltage (150mV max @10mA/1mA), high DC gain (h_FE = 80–250), and AEC-Q101 qualification for automotive-grade reliability in flyback snubber and HV amplifier stages.

For engineers reviewing the ZXTN5551GTA datasheet, ZXTN5551GTA pinout, ZXTN5551GTA application, or ZXTN5551GTA equivalent, key selection criteria include its 160V breakdown rating, thermal resistance of 62.5°C/W (J-A), SOT223 lead-frame construction, and verified performance at 150°C junction temperature under pulsed switching conditions.

Technical Context

This NPN transistor operates with a minimum BV_CEO of 160V and BVCBO of 180V, supporting high-side switching in offline power supplies where voltage transients exceed 100V. Its f_T of 130MHz enables stable amplification up to mid-RF frequencies when biased at V_CE = 10V and I_C = 10mA.

The device uses a planar epitaxial die structure with optimized base doping to sustain h_FE ≥ 80 at I_C = 50mA while maintaining V_CE(sat) ≤ 200mV. Thermal design relies on its 34.05°C/W R_θJL, enabling direct heat conduction through the collector tab to PCB copper.

Key Specifications

Pinout & Package

Package: SOT223 - surface-mount, 4-lead thermally enhanced plastic package with exposed collector tab for direct PCB heat sinking; UL 94V-0 rated, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage NPN transistor applications.

Compared with ZXTN5551E6TA and DZT5551, the ZXTN5551GTA provides superior thermal performance (R_θJA = 62.5°C/W), guaranteed high h_FE, and automotive qualification - making it the only choice for thermally demanding or safety-critical applications requiring long-term reliability.

Availability

ZXTN5551GTA is available at Aetrix Electronics and suitable for switch-mode power supply snubbers, automotive engine control modules, and industrial linear regulator pass elements requiring stable component supply and AEC-Q101 compliance.

Supply support for ZXTN5551GTA 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 is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.

The ZXTN5551GTA belongs to Diodes' high-voltage bipolar transistor product line, engineered specifically for robust switching and amplification in automotive, industrial, and power conversion systems where reliability under thermal and electrical stress is critical.

FAQ

Is ZXTN5551GTA recommended for new designs?

No - Diodes Incorporated explicitly marks ZXTN5551GTA as "NOT RECOMMENDED FOR NEW DESIGN" in its official datasheet (DS33671 Rev. 3-3). It is maintained for legacy system support and second-source continuity, with DZT5551 offered as the designated replacement for new projects.

What is the maximum safe operating area (SOA) limit at 100°C ambient?

At T_A = 100°C, the derated power dissipation is 1.25W (per 2W × [1 − (100−25)/125] linear derating). The SOA curve shows that at V_CE = 80V, the maximum pulsed I_C is 120mA for 10ms pulses - confirmed by Figure 1 in DS33671.

Can ZXTN5551GTA replace BC557 in a high-voltage circuit?

No - BC557 is a PNP transistor with V_CEO = 45V and I_C = 100mA; ZXTN5551GTA is an NPN device with 160V/600mA ratings and incompatible polarity and pinout. Direct substitution would reverse biasing and cause circuit failure.

Does the SOT223 package require special PCB layout considerations?

Yes - the exposed collector tab (Pin 3 and Pin 4) must be soldered to a ≥50mm² copper pour with ≥4 thermal vias to achieve rated R_θJA = 62.5°C/W. Pad layout per AP02001 and thermal relief design per J-STD-020 Level 1 are mandatory for thermal compliance.