MMBT3904 1AM NPN 40V 200mA 300mW Transistor SOT-23

IMMBT3904 1AM NPN 40V 200mA 300mW Transistor SOT-23 serves as a high-performance, surface-mount general-purpose bi-polar junction transistor (BJT) designed for low-power switching and amplification tasks. This device, widely recognized by its “1AM” marking, offers a compact footprint that allows for high-density PCB layouts in modern consumer electronics. Consequently, it provides an ideal solution for designers who need to balance space efficiency with reliable electrical performance. The NPN configuration enables the transistor to handle collector currents up to 200 mA, making it suitable for driving small LEDs, relays, and signal processing stages. Furthermore, its high switching speed ensures that digital circuits maintain signal integrity at high frequencies. Therefore, incorporating this SOT-23 transistor into your design guarantees a robust and industry-standard approach to low-signal management.

Key Features:

• High Switching Speed: The device features low capacitance and short delay times, which facilitate efficient operation in high-frequency switching applications.
• Subminiature SOT-23 Package: The surface-mount design reduces the overall board area required, making it perfect for thin and portable electronic devices.
• Wide Voltage Range: With a 40 V breakdown voltage, this transistor safely handles standard logic-level and medium-voltage power rails.
• Low Saturation Voltage: It maintains low power dissipation during the “on” state, thereby increasing the efficiency of battery-powered systems.
• Standardized Marking: The “1AM” code ensures easy identification and verification during the assembly and inspection processes.

Technical Specifications:

• Transistor Polarity: NPN
• Collector-Emitter Voltage (V_CEO): 40 V maximum
• Collector-Base Voltage (V_CBO): 60 V maximum
• Continuous Collector Current (I_C): 200 mA
• Total Power Dissipation (P_D): 300 mW (at T_A = 25°C)
• DC Current Gain (h_FE): 100 to 300 (at I_C = 10 mA)
• Transition Frequency (f_T): 300 MHz minimum
• Operating Junction Temperature: −55°C to +150°C

Mechanical Specifications:

• Package Type: SOT-23 (TO-236AB)
• Mounting Type: Surface Mount Device (SMD/SMT)
• Lead Finish: Matte Tin (Pb-Free)
• Moisture Sensitivity Level: MSL 1 (Unlimited floor life)

Dimensions:

• Body Length: ≈ 2.9 mm
• Body Width: ≈ 1.3 mm
• Total Height: ≈ 1.0 mm
• Lead Pitch: ≈ 1.9 mm (between outer pins)

Pinout and Wiring:

• Pin 1 (Base): Controls the flow of current between the collector and emitter.
• Pin 2 (Emitter): Connects to the ground or the negative side of the load in a standard common-emitter configuration.
• Pin 3 (Collector): Connects to the load or positive supply rail.
• Wiring Note: Ensure proper current-limiting resistors are placed at the base to prevent thermal runaway and permanent damage to the junction.

Datasheet Reference:

• Download MMBT3904 SOT-23 Transistor Datasheet

Commonly Used in:

• Digital Logic Interfaces: Converting low-current MCU signals to drive slightly higher current loads.
• Signal Amplifiers: Boosting weak signals in audio and radio frequency pre-amplifier stages.
• Pulse Generators: Creating precise timing pulses in oscillation and timing circuits.

Applications:

• LED Switching: Activating indicator lights or small backlit displays in portable gadgets.
• Relay Drivers: Providing the necessary current to trigger small 5 V or 12 V mechanical relays.
• Voltage Regulation: Acting as a pass transistor in low-current linear voltage regulator designs.
• PWM Control: Handling high-speed pulse width modulation for basic motor speed or brightness control.

Equivalent Models:

• 2N3904: The through-hole (TO-92) version of this transistor, sharing identical electrical characteristics.
• BC847: A similar NPN general-purpose transistor in SOT-23, however, it may feature slightly different gain and voltage ratings.
• KST3904: A common alternative manufacturer part number that serves as a direct drop-in replacement.

Package Includes:

• 1 x IMMBT3904 1AM NPN 40V 200mA 300mW Transistor SOT-23