The MMBT3904M is a surface-mount NPN bipolar junction transistor (BJT) manufactured by Jiangsu Changjiang Electronics Technology Co., Ltd (JCET). It is designed for general-purpose amplification and switching applications. This transistor is commonly used in a wide range of electronic circuits due to its reliable performance and small form factor.

Applications:

• Low-noise amplifiers: Used in preamplifiers and amplifier stages where minimizing noise is crucial.
• Switching circuits: Employed in circuits where a small signal is used to control a larger current or voltage.
• Driver stages: Can drive small loads like LEDs or relays in electronic circuits.
• Signal amplification: Used for amplifying small signals in various electronic devices.
• Oscillator circuits: Can be used in simple oscillator designs.

Features:

• NPN Transistor: An NPN transistor allows current flow from collector to emitter when a small current is applied to the base.
• Surface Mount Package: Designed for automated assembly on printed circuit boards (PCBs).
• Low Saturation Voltage: Ensures efficient switching performance with minimal voltage drop.
• High Current Gain (hFE): Provides substantial amplification of the input current.

Benefits:

• Small Footprint: The surface mount package saves valuable board space, allowing for more compact designs.
• High Reliability: Manufactured by JCET to ensure consistent and dependable performance.
• Ease of Use: Simple to implement in various circuits due to its common configuration.
• Cost-Effective: Provides a balance of performance and affordability.

Specifications:

The MMBT3904M typically features a collector-emitter voltage (VCEO) of 40V, a collector current (IC) of 200mA, and a power dissipation of around 300mW. Its transition frequency is typically around 300 MHz, making it suitable for high-frequency applications. The current gain (hFE) typically ranges from 100 to 300, depending on the operating conditions. It is commonly available in a SOT-23 package.