BC859A

Overview

The BC859A is a small-signal PNP bipolar junction transistor manufactured by Diotec Semiconductor, designed for surface-mount applications in the SOT-23 package. It operates with a maximum collector current of 100 mA and a collector-emitter voltage rating of 30 V. The device features three distinct DC current gain (hFE) groups: Group A ranges from 125 to 180, Group B spans 180 to 290, and Group C covers 420 to 520 at an IC of 2 mA. Key electrical characteristics include a collector-emitter saturation voltage of up to 650 mV at 100 mA, a transition frequency of 100 MHz, and a power dissipation capacity of 250 mW. The component supports a junction temperature range of -55°C to +150°C.

Feature Summary

• Offers three standardized current gain groups (A, B, and C) to accommodate varying amplification requirements without custom sorting.
• Constructed with a plastic case material rated UL 94V-0 for mechanical stability and safety compliance.
• Compliant with RoHS directives (without exemption), REACH regulations, and conflict mineral sourcing standards.

Applications

• Signal processing circuits
• Electronic switching applications
• Amplification stages

Procurement Notes

Verify that the specific ordering suffix matches the required reliability grade. The absence of a suffix indicates industrial grade, while the -C suffix denotes commercial grade. Confirm whether automotive qualification via AEC-Q101 is necessary for the target application, as this requires specific -Q or -AQ suffixes. Ensure the procurement documentation references the correct hFE binning group (A, B, or C) to guarantee circuit performance alignment.

Selection Notes

Select the BC859A when a compact SOT-23 PNP transistor is required for general-purpose signal handling. Choose the appropriate hFE group based on the precision needed for the amplifier or switch design; Group A provides lower gain, while Group C offers high gain. Consider the thermal resistance values, which differ between commercial and industrial grades, to ensure adequate heat dissipation within the 250 mW power limit during continuous operation.

Part Context

This component belongs to the BC856...BC860 series of SMD general-purpose PNP transistors produced by Diotec Semiconductor. The series shares common mechanical footprints and basic electrical limits but varies in voltage ratings and gain configurations across different part numbers. The BC859A specifically targets applications requiring 30 V breakdown and standardized gain bins, serving as a complement to NPN counterparts like the BC848A within the same family.

Replacement Considerations

Direct functional substitutes within the same manufacturer series include BC859B and BC859C, which share identical pinouts and maximum ratings but offer different DC current gain ranges. Cross-manufacturer replacements must match the SOT-23 package, 30 V VCEO, and 100 mA IC specifications. Verify that alternative parts support the required hFE group if gain consistency is critical to the circuit design.

FAQ

What distinguishes the BC859A from the BC859B and BC859C?

The primary difference lies in the DC current gain (hFE) groups. The BC859A corresponds to Group A (125-180), the BC859B to Group B (180-290), and the BC859C to Group C (420-520). All other maximum ratings and physical characteristics remain identical.

Does the BC859A meet automotive standards?

The standard BC859A is an industrial grade component. To meet automotive standards, you must select parts with the -Q (AEC-Q101 compliant) or -AQ (AEC-Q101 qualified) suffixes.

What is the maximum power dissipation for this transistor?

The total power dissipation (Ptot) is rated at 250 mW when mounted on a printed circuit board with the minimum recommended pad layout.