1. Core Product Parameters

Limit parameters are tested at 25℃. The collector-base maximum withstand voltage is 60V, the collector-emitter maximum withstand voltage is 40V, and the emitter-base maximum withstand voltage is 6V. The continuous collector current is 0.2A, and collector power dissipation is 0.2W. The maximum junction temperature of the device is 150℃, and the storage temperature ranges from -55℃ to 150℃. Pin definition: Pin 1-Base, Pin 2-Emitter, Pin 3-Collector.

Electrical characteristics are measured at 25℃.
All inter-electrode cut-off leakage currents are at the microampere level. Under specified test conditions, the DC current gain ranges from 100 to 400. The device can be further classified into different grades according to gain values. In saturation state, the maximum collector-emitter saturation voltage is 0.3V, and the maximum base-emitter saturation voltage is 1V. The minimum transition frequency is 300MHz, delivering favorable high-frequency signal processing capability.

2. Core Product Features

First, the SOT-23 surface-mount package features compact size, saves PCB layout space and adapts to automated surface-mount welding production processes. Second, as an NPN transistor, it can form complementary pairing with SL3906 to facilitate the construction of complementary-structure circuits. Third, it features wide temperature adaptability. Its storage temperature ranges from -55℃ to 150℃, meeting the environmental requirements of most consumer electronics and general civil equipment. Fourth, it has a wide DC current gain range, suitable for both small-signal amplification and switch-control operating modes. Fifth, the minimum transition frequency reaches 300MHz for processing high-frequency signals. Sixth, low voltage drop under saturated conduction brings low conduction loss when applied as a switch. Seventh, low inter-electrode leakage current in cut-off state results in low static power consumption when the device is turned off.

3. Main Application Fields

As a general-purpose surface-mount transistor, it is widely used in circuits of various consumer electronic products. It performs small-signal amplification to process weak electrical signals. It works as a low-speed switching component to realize circuit on-off control. It applies to signal switching circuits and level-shift circuits. It can also drive small low-power loads such as micro-indicators. Besides, it can be adopted in various control boards and auxiliary power supply loops and other general electronic circuits.

4. Engineering Design Recommendations

In circuit design, the actual operating voltage, current and power consumption of the device shall be lower than the limit parameters specified in the datasheet. Sufficient safety margin shall be reserved to prevent device damage.

The withstand voltage between emitter and base is only 6V. Special attention shall be paid during circuit design and commissioning to avoid emitter-junction damage caused by overvoltage.

The DC current gain varies with operating current and ambient temperature. Nominal gain cannot be directly adopted for amplifying circuit design. Parameter changes induced by operating points and temperature shall be fully considered.

When used as a switching device, base driving conditions shall be properly configured to ensure reliable saturation of the transistor. Excessive driving current that causes extra loss should also be avoided.

Allowable power dissipation of the device decreases as ambient temperature rises. For high-temperature operating scenarios, reduce actual power consumption of the device to control junction temperature and prevent overheating-induced failure.

Saturation voltage drop and base-emitter voltage are affected by both operating current and temperature. During design, typical characteristic curves in the datasheet can be referenced to evaluate conduction loss combined with practical operating current.

PCB design shall match standard pad dimensions for the SOT-23 package to guarantee welding reliability as well as heat dissipation performance of the device.

5. Product Summary

SL3904 is a general-purpose NPN surface-mount transistor with SOT-23 package. Its withstand voltage and current specifications fit common medium-and-low-power scenarios. It delivers good high-frequency performance, low saturated conduction loss and favorable temperature adaptability. Supporting both signal amplification and switch-control applications, it is a versatile discrete semiconductor component. In practical engineering applications, actual operating conditions of the device must be strictly controlled. Attention should be paid to parameter variations caused by temperature, and reasonable design margin should be reserved to ensure long-term stable circuit operation. This device can satisfy component-selection requirements for most consumer electronics and general-purpose control circuits.

About Slkor：

Slkor has research and development offices in Busan, South Korea, Beijing, China, and Suzhou, China. Most of the wafer manufacturing and packaging and testing are carried out within China. The company employs and collaborates with individuals and organizations worldwide, with a laboratory for product performance and reliability testing and a central warehouse located at its headquarters in Shenzhen. Slkor has filed for over a hundred invention patents, offers more than 2,000 product models, and serves over ten thousand customers globally. Its products are exported to countries and regions including Europe, the Americas, Southeast Asia, and the Middle East, making it one of the rapidly growing semiconductor companies in recent years. With well-established management systems and streamlined workflows, Slkor has rapidly enhanced the brand awareness and reputation of its "SLKOR" brand through its outstanding quality and standardized services. Its product range includes three major series: diodes, transistors, and power devices, with recent introductions of new products such as Hall elements and analog devices, expanding its presence in sensors, Risc-v microcontrollers, and other product categories.