Diodes Incorporated MMBT3904T-13

Overview

MMBT3904T-13 from Diodes Incorporated is an NPN small-signal surface-mount transistor in SOT-523 package, rated for 40 V V_CEO, 200 mA I_C, and 150 mW P_D, used for general-purpose switching and amplification in space-constrained consumer and industrial PCBs.

For engineers reviewing the MMBT3904T-13 datasheet, MMBT3904T-13 pinout, MMBT3904T-13 application, or MMBT3904T-13 equivalent, key selection criteria include DC current gain (h_FE = 40–300), V_CE(SAT) ≤ 0.3 V at 50 mA, f_T = 300 MHz, thermal resistance R_JA = 833 °C/W, and RoHS-compliant lead-free plating.

Technical Context

This epitaxial planar NPN transistor operates across –55°C to +150°C with low leakage (I_CEX ≤ 50 nA at V_CE = 30 V) and fast switching (t_r/t_f = 35/50 ns). Its complementary PNP counterpart is MMBT3906T.

Small-signal parameters include h_fe = 100–400 at 10 mA, C_obo = 4.0 pF at V_CB = 5 V, and NF = 5.0 dB at 1 MHz - confirming suitability for low-noise preamplifier and digital logic interface stages.

Key Specifications

Pinout & Package

SOT-523 ultra-small surface-mount package: 1.1 mm × 1.6 mm footprint, 0.9 mm height, 0.002 g weight, UL 94V-0 rated molded plastic case with matte tin lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC847BW and PN2222A-AP, the MMBT3904T-13 offers superior board-area efficiency and guaranteed RoHS compliance, while maintaining competitive switching speed and noise performance - making it optimal for production-scale SMT assembly of compact, certified end products.

Availability

MMBT3904T-13 is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller interface modules, low-noise preamplifiers, and power supply enable switches requiring stable component supply and long-term manufacturability.

Supply support for MMBT3904T-13 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 centers across Asia and manufacturing in China, Taiwan, and the U.S.

The MMBT3904T belongs to Diodes' standard small-signal transistor product line, engineered for cost-effective, high-yield SMT deployment in consumer, computing, and industrial control systems where reliability and footprint efficiency are prioritized.

FAQ

What is the maximum operating temperature for MMBT3904T-13?

The MMBT3904T-13 is rated for junction and storage temperatures from –55°C to +150°C. Derating begins above +25°C ambient per the power derating curve: P_D decreases linearly to zero at +150°C, with R_JA = 833 °C/W defining the slope. Operation beyond +150°C risks permanent parametric shift or failure.

Is MMBT3904T-13 pin-compatible with other SOT-523 transistors?

Yes - MMBT3904T-13 uses standard SOT-523 pinout (Emitter-Base-Collector on pins 1-2-3), matching industry-layout conventions. However, electrical parameters (e.g., h_FE, V_CE(SAT)) differ across part numbers; direct substitution requires validation of gain, saturation voltage, and thermal behavior in the target circuit.

Does MMBT3904T-13 require a heatsink in typical operation?

No heatsink is required for MMBT3904T-13 at ≤150 mW dissipation on standard FR-4 with Diodes' recommended pad layout (AP02001). Its R_JA = 833 °C/W assumes no added copper thermal relief; adding thermal vias or copper pour can improve dissipation margin but is not necessary for ≤200 mA DC switching at room temperature.

How does the "-13" suffix affect the device specification?

The "-13" suffix denotes tape-and-reel packaging: 3,000 units per reel, optimized for automated SMT placement. It does not alter electrical or thermal specifications - all performance parameters match the base MMBT3904T, including V_CEO = 40 V, h_FE = 40–300, and RoHS compliance. The marking "1N" appears on the device body regardless of reel suffix.