Diodes Incorporated ZXTN4240F-7

Overview

ZXTN4240F-7 from Diodes Incorporated is a 40V NPN low-saturation transistor in SOT23 package, rated for 2A continuous collector current and 3A peak pulse current, with V_CE(SAT) ≤ 180 mV at I_C = 1 A and R_CE(SAT) = 60 mΩ at 0.5 A - optimized for high-efficiency switching in automotive load control and industrial power management circuits.

For engineers reviewing the ZXTN4240F-7 datasheet, ZXTN4240F-7 pinout, ZXTN4240F-7 application, or ZXTN4240F-7 equivalent, key selection criteria include its AEC-Q101 qualification, low on-resistance under high-current drive, thermal resistance of 75 °C/W (junction-to-lead), and complementary PNP pairing with ZXTP5240F for H-bridge designs.

Technical Context

This NPN bipolar junction transistor operates as a high-current, low-V_CE(SAT) switch with DC current gain (h_FE) ≥ 300 at I_C = 0.5–1 A and ≥ 150 at I_C = 2 A, supporting stable gain across -55°C to +150°C ambient range. Its f_T = 100 MHz enables fast switching in PWM-driven loads.

Designed for thermally constrained PCB layouts, it delivers 730 mW power dissipation on 15 mm × 15 mm 1 oz copper, with R_θJA = 171 °C/W (note 5) and R_θJL = 75 °C/W - enabling direct thermal coupling to copper pour or lead-based heatsinking without external heatsinks.

Key Specifications

Pinout & Package

Package: SOT23 - surface-mount plastic case, 0.008 g weight, UL 94V-0 rated molding compound, matte tin-plated leads solderable per MIL-STD-202 Method 208.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBT4401-7-F and DMT3005LPS-13, ZXTN4240F-7 uniquely balances 2 A current capability, 180 mV saturation, AEC-Q101 qualification, and direct 3.3 V/5 V GPIO drivability - making it optimal for space-constrained, thermally demanding automotive and industrial switches where BJT simplicity and robustness are prioritized over MOSFET ultra-low R_DS(on).

Availability

ZXTN4240F-7 is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC output stages, and DC motor control requiring stable component supply, long-term lifecycle assurance, and AEC-Q101 compliance.

Supply support for ZXTN4240F-7 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 components for automotive, industrial, and computing markets.

ZXTN4240F belongs to Diodes' AEC-Q101-qualified low-saturation transistor product line, engineered specifically for thermally efficient, high-current switching in space-constrained automotive and industrial control modules.

FAQ

What is the maximum safe operating temperature for ZXTN4240F-7?

The device is rated for junction temperatures from -55°C to +150°C. Under continuous 2 A operation on a 15 mm × 15 mm 1 oz copper PCB, thermal calculations using R_θJA = 171 °C/W show T_J ≈ 125°C at 25°C ambient - well within spec. Derating is required above 85°C ambient per the datasheet's derating curve.

Can ZXTN4240F-7 be driven directly by a 3.3 V microcontroller GPIO?

Yes - with I_C = 2 A, the required base current is 200 mA (per datasheet test condition). A 3.3 V GPIO cannot source this directly; however, a 3.3 V logic signal can drive a small-signal BJT or logic-level MOSFET that then supplies the 200 mA base current. The ZXTN4240F itself is not logic-level compatible but is designed for such staged drive.

Is there a recommended PCB layout for thermal performance?

Yes - the datasheet specifies a minimum pad layout: 2.0 mm × 0.8 mm collector pad, 1.35 mm × 0.9 mm emitter pad, and 2.9 mm × 0.9 mm overall footprint. For best thermal performance, connect the collector pad to ≥ 15 mm × 15 mm internal or external copper pour with ≥ 4 thermal vias to inner ground planes.

How does ZXTN4240F-7 compare to its PNP complement ZXTP5240F?

ZXTP5240F shares identical voltage/current ratings (40 V V_CEO, 2 A I_C), saturation performance (V_EC(SAT) ≤ 180 mV), and AEC-Q101 qualification. Pinout is mirrored (Emitter-Base-Collector vs. Collector-Base-Emitter), enabling matched-pair use in push-pull and H-bridge topologies with symmetrical thermal and switching behavior.