Diodes Incorporated MMBT3904LP-7B

Overview

MMBT3904LP-7B from Diodes Incorporated is a 40V NPN small-signal transistor in X1-DFN1006-3 package, rated for 200mA collector current and 1000mW power dissipation (with exposed pad thermal enhancement), featuring BV_CEO > 40V, V_BE(sat) ≤ 0.85V at I_C=10mA/I_B=1mA, and f_T = 300MHz - used in compact load switching and signal amplification stages of portable power management and sensor interface circuits.

For engineers reviewing the MMBT3904LP-7B datasheet, MMBT3904LP-7B pinout, MMBT3904LP-7B application, or MMBT3904LP-7B equivalent, key selection criteria include its 0.5mm height, 0.60mm² footprint (13× smaller than SOT-23), JEDEC-qualified reliability, NiPdAu terminal finish, and complementary pairing with MMBT3906LP for push-pull designs.

Technical Context

This NPN bipolar junction transistor operates in linear and saturated switching modes with DC current gain (h_FE) ranging from 40 to 300 across I_C = 100µA–100mA and V_CE = 1.0V. Its low V_CE(sat) (≤0.30V at I_C=50mA/I_B=5mA) and fast switching (t_d/t_r/t_f ≤ 35/35/50ns) support efficient digital logic interfacing and PWM-driven loads.

Thermally, it leverages an exposed collector pad to achieve R_θJL = 120°C/W and R_θJA = 120°C/W on 25mm × 25mm 2oz copper - enabling high-power-density operation within -55°C to +150°C ambient range while maintaining ESD robustness (HBM 4kV, MM 200V).

Key Specifications

Pinout & Package

Package: X1-DFN1006-3 - 0.5mm height, 1.0 × 0.6mm body, exposed collector pad (pin 3), NiPdAu-plated terminals, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN small-signal transistor applications.

Compared with MMBT3904-7-F, the MMBT3904LP-7B delivers 61% better thermal resistance and 13× smaller area; versus BC847BW, it offers 2× higher I_C, tighter h_FE consistency, and JEDEC-qualified reliability for industrial deployment.

Availability

MMBT3904LP-7B is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO expansion, sensor signal conditioning, and power supply enable switching requiring stable component supply across production lifecycles.

Supply support for MMBT3904LP-7B 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-performance, high-reliability components for industrial, computing, and automotive markets.

The MMBT3904LP belongs to Diodes' precision small-signal transistor product line, engineered for space-constrained, thermally demanding applications where miniaturization and JEDEC-qualified robustness are mandatory.

FAQ

What is the maximum continuous collector current for MMBT3904LP-7B under typical PCB conditions?

The device is rated for 200mA continuous collector current (I_C) when mounted on a 25mm × 25mm 2oz copper pad, achieving 1000mW power dissipation. On minimal pad layout, derating applies: at 25°C ambient, max I_C drops to ~113mA due to higher R_θJA = 310°C/W. Always verify thermal design using transient curves in Figure 2.

Does MMBT3904LP-7B support automotive-grade applications?

MMBT3904LP-7B itself is not AEC-Q200 qualified, but Diodes offers automotive-grade variants (e.g., MMBT3904Q-7B) with PPAP documentation, IATF 16949 manufacturing, and extended temperature validation. For non-safety automotive subsystems where AEC-Q is not mandated, this part may be used with customer-specific qualification.

How is the exposed collector pad on the X1-DFN1006-3 package electrically and thermally connected?

The exposed collector pad (pin 3) is internally bonded to the transistor's collector region and must be soldered directly to a PCB copper pour for both electrical connection and thermal conduction. It is not isolated; connecting it to ground or other potentials will short the collector. Use thermal vias beneath the pad to enhance heat transfer to inner layers.

Can MMBT3904LP-7B replace traditional SOT-23 transistors in existing designs without layout changes?

No - the X1-DFN1006-3 package (1.0 × 0.6mm) is incompatible with SOT-23 footprints (3.0 × 1.4mm). Layout redesign is required, including new pad geometry, stencil aperture, and thermal via placement. However, the identical electrical characteristics (BV_CEO, h_FE, V_CE(sat)) simplify schematic reuse and validation.