NXP Semiconductors BC640,112

Overview

BC640,112 from Nexperia (formerly Philips Semiconductors) is a PNP medium-power bipolar junction transistor in TO-92 (SOT54) package, rated for −80 V V_CEO, −100 V V_CBO, and −1 A continuous collector current. It delivers DC current gain (h_FE) of 63–250 at I_C = −150 mA and exhibits V_CE(sat) ≤ −0.5 V at I_C = −500 mA / I_B = −50 mA, making it suitable for audio amplifier output stages and switching regulators.

For engineers reviewing the BC640,112 datasheet, BC640,112 pinout, BC640,112 application, or BC640,112 equivalent, key selection criteria include its PNP polarity, −80 V V_CEO rating, TO-92 thermal resistance (R_th(j-a) = 150 K/W), h_FE consistency across I_C range, and compatibility with BC639 NPN complement in push-pull configurations.

Technical Context

The BC640,112 operates as a general-purpose PNP BJT optimized for linear amplification and medium-speed switching up to 100 MHz (f_T). Its design emphasizes stable h_FE across collector currents from −5 mA to −500 mA and low saturation voltage under moderate drive conditions.

It features complementary pairing capability with BC639 (NPN), validated by h_FE1/h_FE2 ratio ≤ 1.6 at |V_CE| = 2 V and |I_C| = 150 mA - enabling matched gain performance in differential or push-pull topologies without external trimming.

Key Specifications

Pinout & Package

BC640,112 is housed in a plastic single-ended leaded (through-hole) TO-92 package, designated SOT54 per JEDEC and SC-43A per Philips. Dimensions: L = 14.5 mm, D = 4.8 mm, E = 4.2 mm, e = 2.54 mm (lead pitch), with 3 leads spaced on 2.54 mm centers.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP medium-power transistor applications.

Compared with BC640,114, the BC640,112 offers identical performance in a smaller reel format suited for bench use; versus MPSA92, it trades off voltage headroom for superior gain linearity and lower conduction loss - critical in audio and regulated power applications.

Availability

BC640,112 is available at Aetrix Electronics and suitable for audio amplifier output stages, DC-DC converter switches, and relay driver circuits requiring stable component supply, consistent parametric performance, and through-hole manufacturability.

Supply support for BC640,112 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Nexperia is a global semiconductor expert formed from the former Standard Products division of Philips, specializing in high-volume, high-reliability discrete and logic devices.

The BC640,112 belongs to Nexperia's legacy general-purpose BJT family designed for cost-sensitive, medium-power linear and switching applications in consumer, industrial, and automotive auxiliary systems.

FAQ

What is the maximum collector-emitter voltage rating for BC640,112?

The BC640,112 has a maximum collector-emitter voltage (V_CEO) rating of −80 V with the base open. This value is specified under absolute maximum conditions per IEC 60134 and defines the upper limit for safe DC or peak repetitive voltage applied between collector and emitter. Exceeding this rating risks permanent device failure. The BC640,112 datasheet confirms this parameter in the Limiting Values table on page 3.

Is BC640,112 pin-compatible with BC639?

No, BC640,112 is not pin-compatible with BC639. BC640,112 is a PNP transistor with pinout Base–Collector–Emitter (1–2–3), while BC639 is an NPN transistor with identical physical TO-92 package but same pinout order - meaning their polarities differ, not pin assignments. They are complementary in function and gain matching, not physical layout. Always verify schematic symbol orientation and PCB footprint polarity when using BC640,112 alongside BC639.

What is the thermal resistance of BC640,112 and how does it affect PCB layout?

The BC640,112 has a junction-to-ambient thermal resistance (R_th(j-a)) of 150 K/W when mounted on a standard FR4 printed-circuit board. This means each watt of power dissipated raises the junction temperature by 150 °C above ambient. To maintain T_j ≤ 150 °C at full 0.83 W dissipation, ambient must stay below 25 °C - so adequate copper pour, spacing from heat sources, and airflow are essential. The BC640,112 datasheet specifies this in the Thermal Characteristics section on page 3.

Does BC640,112 have a guaranteed minimum DC current gain at high collector current?

Yes, BC640,112 guarantees a minimum DC current gain (h_FE) of 40 at I_C = −500 mA and V_CE = −2 V, as confirmed in the Characteristics table on page 4 of the datasheet. This ensures predictable base drive requirements even near maximum current, supporting robust switching and linear operation without gain collapse. The h_FE range expands to 63–250 at I_C = −150 mA, offering design flexibility across operating points.

Can BC640,112 be used as a direct replacement for BC638 in existing designs?

No, BC640,112 is not a direct replacement for BC638. While both are PNP TO-92 transistors, BC638 has lower voltage ratings: −60 V V_CBO and −60 V V_CEO, versus −100 V and −80 V for BC640,112. Substituting BC640,112 may be acceptable if the circuit operates well within BC638's limits - but reverse substitution (BC638 for BC640,112) risks overvoltage failure. Always validate stress margins and h_FE variation before interchanging BC640,112 and BC638.