Diodes Incorporated ZXTN04120HKTC

Overview

ZXTN04120HKTC from Diodes Incorporated is a 120V NPN medium-power Darlington transistor in TO252 (DPAK) package, designed for high-voltage switching with BV_CEO > 120 V, continuous collector current I_C = 1.5 A, and DC current gain h_FE > 2,000 at 1 A. It serves as a high-gain output stage in relay drivers, DC fan control, and solenoid interfaces where robust voltage blocking and low saturation voltage are required.

For engineers reviewing the ZXTN04120HKTC datasheet, ZXTN04120HKTC pinout, ZXTN04120HKTC application, or ZXTN04120HKTC equivalent, key selection criteria include its 140 V BVCBO rating, 1.5 W power dissipation on 25 mm × 25 mm 1 oz copper, 1.5 V V_CE(sat) at 1 A, AEC-Q101 qualification, and TO252 thermal performance with R_θJC = 11 °C/W.

Technical Context

This Darlington pair integrates two NPN transistors in a single TO252 package to deliver high current gain while maintaining voltage capability up to 120 V V_CEO. Its structure enables low base drive requirements-e.g., only 1 mA IB needed for 1 A IC-with V_BE(sat) ≤ 1.8 V and f_T = 150 MHz under specified conditions.

Thermal design is enabled by the exposed collector pad, offering R_θJC = 11 °C/W and R_θJL = 9 °C/W. Safe operating area (SOA) supports pulsed operation up to 4 A I_CM, with derating curves defined for 25 mm × 25 mm and 50 mm × 50 mm copper layouts.

Key Specifications

Pinout & Package

Package: TO252 (DPAK), surface-mount, with exposed collector pad for thermal and electrical connection. Molded green compound, UL 94V-0 rated, 0.34 g mass.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Darlington transistor applications.

Compared with ZTX1048A and MJD122G, ZXTN04120HKTC uniquely combines 120 V V_CEO, AEC-Q101 qualification, and TO252 thermal performance-making it optimal for high-reliability 48–100 V switching where voltage margin and automotive compliance are mandatory.

Availability

ZXTN04120HKTC is available at Aetrix Electronics and suitable for DC fan control, relay driving, solenoid actuation, and linear regulator applications requiring stable component supply, long-term lifecycle support, and automotive-grade reliability.

Supply support for ZXTN04120HKTC 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, specializing in high-reliability, energy-efficient components for automotive, industrial, and consumer markets.

ZXTN04120HKTC belongs to Diodes' high-voltage Darlington transistor product line, engineered for robust switching in demanding 24–100 V DC systems where gain, voltage margin, and thermal performance are critical.

FAQ

What is the maximum safe operating voltage for ZXTN04120HKTC in continuous DC applications?

The ZXTN04120HKTC has a guaranteed minimum V_CEO of 120 V and V_CBO of 140 V. For continuous DC operation, the absolute maximum recommended collector-emitter voltage is 120 V per datasheet Absolute Maximum Ratings. Derating is not specified, but design margin should maintain ≤100 V in production systems to accommodate transients and temperature effects.

Can ZXTN04120HKTC be used in PWM-driven inductive loads without external flyback protection?

No. While the device withstands 140 V V_CBO, it lacks integrated flyback diode or clamp. Inductive loads like relays and solenoids require an external reverse-biased diode (e.g., 1N4007) across the load to suppress voltage spikes during turn-off and prevent junction breakdown.

How does the TO252 package's exposed collector pad affect PCB layout requirements?

The exposed collector pad must be soldered to a dedicated copper pour connected to the system's power ground or low-side return. Diodes recommends a minimum 50 mm × 50 mm 2 oz copper area for full 3.9 W power dissipation; smaller pads (e.g., 25 mm × 25 mm 1 oz) reduce PD to 2 W and require thermal derating per the datasheet curve.

Is ZXTN04120HKTC suitable for linear regulator applications with >2 V dropout?

Yes. With a maximum V_CE(sat) of 1.5 V at 1 A and 3.9 W power dissipation on optimized PCB, it supports linear regulation with up to ~2.6 V dropout at 1.5 A (P = V_drop × I_out). Thermal design must follow the R_θJA = 32 °C/W condition using 50 mm × 50 mm 2 oz copper to avoid exceeding T_J = 150 °C.