BD646-S

Overview

The BD646-S is a PNP Darlington bipolar junction transistor manufactured by Bourns Inc. It features a collector-emitter voltage rating of 60 V and a continuous collector current capacity of 8 A. The device delivers a minimum DC current gain (hFE) of 750 at a collector current of 3 A with a 3 V bias. Packaged in a through-hole TO-220 form factor, it supports a power dissipation of 2 W at 25°C case temperature, derating linearly to 150°C at 0.4 W/°C.

Feature Summary

• High DC current gain capability for efficient signal amplification
• Robust 8 A continuous collector current handling
• Through-hole TO-220 package for reliable thermal management

Applications

• Power switching circuits requiring high current drive
• Linear amplifier stages utilizing Darlington configurations
• Industrial control systems needing robust PNP transistors

Procurement Notes

Verify the specific suffix designation carefully during procurement. Official documentation indicates conflicting RoHS compliance statuses across different sources. Confirm lifecycle status as obsolete or active with the manufacturer prior to ordering. Ensure the TO-220 package variant matches the required thermal dissipation profile for the target application environment.

Selection Notes

Select this component when a high-gain PNP Darlington configuration is required for medium-power applications. The 60 V rating suits low-voltage switching tasks. Consider the thermal derating characteristics for high-temperature environments. Verify that the 8 A current limit aligns with the load requirements without exceeding the safe operating area defined in the official datasheet.

Part Context

This part belongs to Bourns' single bipolar transistor lineup, specifically within the Darlington transistor category. It complements other high-current PNP devices in the series, offering enhanced current gain compared to standard bipolar transistors. The TO-220 packaging ensures compatibility with standard heatsinking methods for industrial and commercial electronics.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Consult the manufacturer for direct replacements due to the obsolete lifecycle status indicated in some sources.