BD438

Overview

The BD438 is a PNP silicon epitaxial-base power transistor manufactured by STMicroelectronics. It is housed in a SOT-32 plastic package and designed for medium-power linear and switching applications. Key electrical specifications include a maximum collector-emitter voltage (VCEO) of 45 V, a maximum collector-base voltage (VCBO) of 45 V, and a maximum emitter-base voltage (VEBO) of 5 V. The device supports a maximum DC collector current (Idc) of 4 A and has a minimum DC current gain (hFE) of 30. It features a maximum power dissipation (Pd) of 36 W and a maximum transition frequency (ft) of 3 MHz. The component operates at temperatures up to 150°C and utilizes a single transistor configuration with three pins.

Feature Summary

• Complementary PNP counterpart to the BD437 NPN transistor within the same series
• Designed for use in medium power linear and switching applications
• Suitable for car-radio output stages

Applications

• Car-radio output stages
• Medium power linear applications
• Switching applications

Procurement Notes

Verify the specific datasheet version and ordering information directly from STMicroelectronics or authorized distributors. Confirm that the SOT-32 package and pinout match your design requirements. Ensure compliance with RoHS and other relevant environmental standards if applicable. Check for any specific handling instructions related to the surface-mount technology used in this component.

Selection Notes

Select the BD438 when a PNP power transistor with 45 V voltage rating and 4 A current capability is required. Consider its complementary relationship with the BD437 for push-pull configurations. Evaluate the thermal performance given the 36 W power dissipation limit in the SOT-32 package. Ensure the application does not exceed the 150°C maximum junction temperature.

Part Context

The BD438 belongs to a family of complementary silicon power transistors that includes the BD433, BD434, BD435, BD436, BD437, and BD438. These devices are intended for medium-power applications and share similar packaging and structural characteristics. The BD438 specifically serves as the PNP complement to the BD437 NPN transistor, enabling balanced circuit designs in audio and power management systems.

Replacement Considerations

The BD438 is part of a complementary pair with the BD437. For direct replacement, ensure the substitute component matches the PNP polarity, 45 V voltage ratings, 4 A current capacity, and SOT-32 package type. Verify that the replacement meets the same hFE and ft specifications for equivalent performance.