onsemi BC640ZL1

Overview

BC640ZL1 from ON Semiconductor is a PNP silicon bipolar junction transistor (BJT) designed for medium-power linear and switching applications. It features −80 V V_CEO, −500 mA continuous collector current, 1.5 W total device dissipation at T_C = 25°C, and DC current gain (h_FE) of 40–160 at I_C = −150 mA. It is commonly used in power supply regulation, relay drivers, and low-frequency amplifier stages.

For engineers reviewing the BC640ZL1 datasheet, pinout, applications, or equivalent options, key selection criteria include its −80 V breakdown rating, TO-92 package thermal limits, saturation voltage under −500 mA load, and h_FE consistency across temperature for stable bias design.

Technical Context

The BC640ZL1 operates as a general-purpose PNP BJT with fixed-emitter configuration and base-controlled conduction. Its safe operating area supports pulsed currents up to −1 A at reduced V_CE, and its f_T of 150 MHz enables use in audio-frequency amplification and low-speed switching.

Thermal performance is defined by R_JC = 83.3°C/W and R_JA = 200°C/W, requiring heatsinking only when dissipating >0.75 W continuously at ambient. The device exhibits V_BE(on) ≈ −1.0 V and V_CE(sat) ≤ −0.5 V at I_C/I_B = 10, confirming suitability for saturated-switching topologies.

Key Specifications

Pinout & Package

BC640ZL1 is housed in a TO-92 plastic package (Case 29, Style 14), with standardized lead formation and epoxy molding for industrial reliability. Pin assignment follows E-C-B order (Emitter–Collector–Base) when viewing the flat side with leads downward.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC640-16, BC640ZL1 offers broader h_FE tolerance and lower cost but less precision in high-gain-critical circuits; versus MJD127G, it trades power handling for compactness and ease of assembly-making BC640ZL1 ideal for board-level signal and medium-power control where TO-92 fit and thermal budget are constraints.

Availability

BC640ZL1 is available at Aetrix Electronics and suitable for power supply regulation, relay driver circuits, and audio amplifier stages requiring stable component supply, long-term manufacturability, and RoHS-compliant sourcing.

Supply support for BC640ZL1 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

ON Semiconductor (now part of onsemi) is a global semiconductor supplier specializing in energy-efficient electronics, with core expertise in power management, analog, sensors, and discrete devices.

The BC640ZL1 belongs to ON Semiconductor's general-purpose bipolar transistor product line, engineered for industrial control, power conversion, and signal conditioning applications where reliability, thermal robustness, and standardized packaging are essential.

FAQ

What is the maximum collector-emitter voltage rating for BC640ZL1?

The BC640ZL1 has a maximum collector-emitter voltage (V_CEO) rating of −80 V DC. This value is specified under test conditions of I_C = −10 mA and I_B = 0, and represents the highest reverse-biased voltage the transistor can withstand before breakdown. Exceeding this rating risks permanent damage. The BC640ZL1 datasheet confirms this parameter applies specifically to the BC640 variant group, including BC640ZL1.

Is BC640ZL1 pin-compatible with BC638ZL1?

No, BC640ZL1 is not pin-compatible with BC638ZL1 in terms of electrical specifications, though both share the same TO-92 package and E-C-B pinout. The BC638ZL1 has a lower V_CEO (−60 V) and different h_FE range (25–100), making it unsuitable as a direct substitute where −80 V blocking or higher gain is required. Always verify circuit margin against BC640ZL1's −80 V rating before substitution.

What is the typical DC current gain (hFE) of BC640ZL1 at 150 mA collector current?

The BC640ZL1 exhibits a DC current gain (h_FE) of 40 to 160 when tested at I_C = −150 mA and V_CE = −2.0 V DC. This range reflects manufacturing variance across the production lot; design margins should accommodate the minimum value (40) for worst-case base drive calculation. The BC640ZL1 datasheet explicitly lists this h_FE band for the BC640 family, confirming applicability to BC640ZL1.

Does BC640ZL1 support Pb-free soldering processes?

Yes, BC640ZL1 is available in both standard and Pb-free versions; the Pb-free variant is designated BC640ZL1G. It complies with JEDEC J-STD-020 moisture sensitivity level (MSL) 1 and supports standard reflow profiles up to 260°C peak. The BC640ZL1G marking includes a microdot to indicate Pb-free construction, per ON Semiconductor's Pb-Free Packaging Strategy referenced in the official BC638/D datasheet.

What thermal resistance values apply to BC640ZL1 in TO-92 package?

The BC640ZL1 has a junction-to-case thermal resistance (R_JC) of 83.3°C/W and junction-to-ambient resistance (R_JA) of 200°C/W, measured under standard test conditions (T_A = 25°C, free-air convection). These values are confirmed in the "Thermal Characteristics" table of the BC638/D datasheet and apply identically to BC640ZL1 due to identical TO-92 construction and die attach methodology.