Diodes Incorporated ZTX1048A

Overview

ZTX1048A from Diodes Incorporated is an NPN silicon planar medium-power high-gain transistor rated for 4 A continuous collector current, 50 V collector-base breakdown voltage (V_(BR)CBO), and 17.5 V collector-emitter breakdown voltage (V_CEO). It delivers low saturation voltages down to 27 mV at I_C = 0.5 A / I_B = 10 mA and supports pulse currents up to 20 A, making it suitable for switching in LCD backlight converters and DC-DC converter primary-side drivers.

For engineers reviewing the ZTX1048A datasheet, ZTX1048A pinout, ZTX1048A application, or ZTX1048A equivalent, key selection criteria include its V_CEO = 17.5 V rating, h_FE = 450 at I_C = 4 A, V_CE(sat) ≤ 245 mV under full load, thermal capability up to +200 °C junction temperature, and E-Line package mechanical compatibility with through-hole PCB layouts.

Technical Context

The ZTX1048A operates as a medium-power NPN bipolar junction transistor optimized for high-current switching with low on-state loss. Its design emphasizes high DC current gain (h_FE ≥ 220 at I_C = 4 A) and fast switching performance (t_on = 130 ns, t_off = 180 ns) under 10 V supply conditions with 40 mA base drive.

It features robust ruggedness with V_CEV = 50 V (collector-emitter voltage with emitter-base biased), enabling safe operation during inductive turn-off transients. The device is characterized across –55 °C to +200 °C, supporting automotive-grade thermal environments despite not being AEC-Q101 qualified per official documentation.

Key Specifications

Pinout & Package

The ZTX1048A is housed in the E-Line (TO-92 variant) through-hole package, featuring three leads in a straight-line configuration with lead spacing of 2.54 mm (e2) and overall length of 13.50 mm. The package is designed for manual or wave-solder assembly and provides mechanical stability for medium-power dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZTX1051A and BCP56-10, the ZTX1048A offers superior pulse-current capability and higher gain at full load, but has the lowest V_CEO; it remains optimal for cost-sensitive, through-hole, thermally stable 12–18 V switching where fast turn-on and minimal conduction loss are prioritized.

Availability

ZTX1048A is available at Aetrix Electronics and suitable for LCD backlight converters, emergency lighting systems, and DC-DC converters requiring stable component supply and long-term manufacturing continuity.

Supply support for ZTX1048A 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, manufacturing, and sales operations across Asia, Europe, and North America.

The ZTX series targets medium-power bipolar switching applications, emphasizing high gain, low saturation voltage, and rugged thermal performance for industrial and automotive-adjacent power conversion designs.

FAQ

Is the ZTX1048A AEC-Q101 qualified?

No, the ZTX1048A is not AEC-Q101 qualified. While Diodes states that parts qualified to AEC-Q100/101/104/200 are available upon request, the ZTX1048A datasheet explicitly notes it is "not recommended for new designs" and makes no claim of automotive qualification. Engineers requiring AEC compliance must contact Diodes directly for approved alternatives.

What is the maximum safe operating voltage for ZTX1048A in switching mode?

The absolute maximum collector-emitter voltage is V_CEO = 17.5 V, and V_CEV = 50 V applies only with 1 V forward bias on the emitter-base junction. For reliable switching operation, the applied V_CE must remain ≤17.5 V under all conditions, including transient spikes; external clamping is required if inductive loads exceed this rating.

Can ZTX1048A replace ZTX1049A in existing designs?

No - the ZTX1049A is a PNP counterpart with complementary polarity, different pinout (C-B-E vs. E-B-C), and distinct electrical characteristics including negative V_CEO. Direct substitution would reverse current flow and likely damage the circuit; board-level redesign and schematic validation are mandatory for any PNP-to-NPN change.

What thermal derating applies above +25°C ambient?

The ZTX1048A's 1 W power dissipation rating assumes T_amb = +25°C. Derating is linear at 8.0 mW/°C above +25°C, meaning maximum allowable power drops to 0.6 W at +75°C ambient. Effective heatsinking or forced airflow is required to sustain 4 A continuous current beyond room temperature.