FFB3946

Overview

The FFB3946 is a complementary dual general-purpose amplifier and switch transistor housed in an SC70-6 surface-mount package. It integrates one NPN and one PNP bipolar junction transistor within a single six-lead footprint, designed to reduce board space and component count. The device supports continuous collector currents up to 200 mA and operates with a collector-emitter voltage of 40 V. Key electrical characteristics include a DC current gain (hFE) ranging from 40 to 300 at 10 mA, a saturation voltage of 0.25 V max, and a transition frequency of 200 MHz. Total power dissipation is rated at 300 mW.

Feature Summary

• Integrates complementary NPN and PNP transistors into a single compact surface-mount package for simplified circuit design.
• Optimized for general-purpose amplification and switching applications with high current handling capabilities.
• Features low collector-emitter saturation voltage to minimize power loss during conduction.

Applications

• General-purpose signal amplification circuits
• Low-power switching applications
• Complementary push-pull output stages

Procurement Notes

Verify the specific package variant required, as the FFB3946 designation corresponds to the SC70-6 package, while the FMB3946 variant utilizes the SSOT-6L package. Confirm that the ordering suffix matches the desired physical footprint before finalizing procurement. Ensure compliance with RoHS standards and verify that the source distributor provides traceability documentation to mitigate counterfeit risks associated with legacy Fairchild Semiconductor part numbers now managed by ON Semiconductor.

Selection Notes

Select this component when board space constraints require integrating both NPN and PNP functions into a single footprint. The device is suitable for applications requiring a collector-emitter breakdown voltage of at least 40 V and continuous currents up to 200 mA. Consider the thermal resistance of 415 °C/W when designing for ambient temperatures above 25°C, as total power dissipation is limited to 300 mW. Verify that the required current gain falls within the specified range of 40 to 300 for the target operating current.

Part Context

This component originates from the Fairchild Semiconductor portfolio and has been integrated into the ON Semiconductor product line following corporate acquisition. The datasheet notes that Fairchild orderable part numbers containing underscores were updated to dashes to align with ON Semiconductor system requirements. The FFB3946 serves as a complementary pair equivalent to discrete FFB3904 (NPN) and FFB3906 (PNP) devices, offering a consolidated solution for general-purpose amplifier designs.

Replacement Considerations

The MBT3946DW1T2G is a documented complementary dual transistor alternative available in an SOT-363-6 package. While functionally similar, the pinout and physical dimensions differ between the SC70-6 and SOT-363 packages, requiring layout verification during substitution.