Nexperia USA Inc. MMBT3904-QR

Overview

MMBT3904-QR from Nexperia is an AEC-Q101-qualified NPN bipolar junction transistor in SOT23 package, rated for 40 V V_CEO, 200 mA I_C, and DC current gain (h_FE) of 100–300 at I_C = 10 mA. It serves as a general-purpose switching device in automotive signal routing, LED driver biasing, and logic-level translation circuits.

For engineers reviewing the MMBT3904-QR datasheet, MMBT3904-QR pinout, MMBT3904-QR application, or MMBT3904-QR equivalent, key selection criteria include its automotive qualification, low V_CE(sat) (≤850 mV at I_C/I_B = 10 mA/1 mA), thermal resistance (500 K/W), and SOT23 footprint compatibility with high-density PCB layouts.

Technical Context

This discrete NPN transistor operates in active or saturation mode for digital switching and small-signal amplification. Its h_FE varies from 60 to 300 across I_C = 0.1–100 mA and temperature range −55 °C to +150 °C, with guaranteed minimum h_FE = 100 at V_CE = 1 V and I_C = 10 mA.

Switching performance is characterized by t_d ≤ 35 ns, t_r ≤ 35 ns, t_s ≤ 200 ns, and t_f ≤ 50 ns under defined test conditions (I_Bon = 1 mA, I_Boff = −1 mA). V_BE(sat) remains ≤950 mV at I_C = 50 mA and I_B = 5 mA, supporting robust base drive margin in automotive control nodes.

Key Specifications

Pinout & Package

SOT23 (SC-70) plastic surface-mount package: 3-terminal, 1.9 mm pitch, 2.9 mm × 1.3 mm × 1.0 mm body. RoHS-compliant, halogen-free, qualified per AEC-Q101.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NSS40301MR6T5G and DXT3904TC-7-F, the MMBT3904-QR offers optimal balance of thermal performance, footprint size, and automotive qualification assurance in the widely adopted SOT23 package - making it preferred for production designs requiring proven manufacturability and field reliability.

Availability

MMBT3904-QR is available at Aetrix Electronics and suitable for automotive body electronics, LED lighting control, and microcontroller interface expansion requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MMBT3904-QR 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

Nexperia is a global semiconductor expert specializing in high-volume, high-reliability discrete and logic devices, with leadership in automotive-qualified components and advanced packaging technologies.

The MMBT3904-QR belongs to Nexperia's AEC-Q101-qualified general-purpose transistor family, engineered specifically for robust, cost-effective switching in automotive control modules, body electronics, and power management subsystems.

FAQ

Is MMBT3904-QR pin-compatible with standard MMBT3904 variants?

Yes - MMBT3904-QR uses identical SOT23 pinout (Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector) and shares all electrical specifications with non-automotive MMBT3904 parts. The "-QR" suffix denotes AEC-Q101 qualification and enhanced traceability; no circuit redesign is needed for drop-in replacement in existing layouts.

What is the maximum allowable continuous power dissipation at 85 °C ambient?

At T_amb = 85 °C, derated P_tot = 250 mW × (1 − (85 − 25)/500) = 250 mW × 0.88 = 220 mW. This assumes mounting on FR4 PCB with single-sided copper and standard SOT23 footprint per datasheet condition [1]; forced convection or thermal vias may improve actual dissipation.

Can MMBT3904-QR be used in linear amplification applications?

Yes - its h_FE stability (100–300) and f_T = 300 MHz support low-noise, low-distortion small-signal amplification up to ~100 kHz. However, thermal limitations (R_th(j-a) = 500 K/W) restrict usable quiescent current; bias networks must ensure V_CE remains within 1–10 V and I_C ≤ 50 mA for stable operation.

Does MMBT3904-QR support wave soldering?

Yes - Nexperia provides dedicated wave soldering footprint (Fig. 9) with 2.8 mm × 4.5 mm land pattern and 1.4 mm solder resist openings. Peak temperature must not exceed 260 °C for ≤5 seconds; preheat ramp rate ≤2 °C/s and dwell time at >100 °C limited to 90–120 seconds per JEDEC J-STD-020.