onsemi BSS63

Overview

BSS63 from ON Semiconductor is a PNP bipolar junction transistor (BJT) designed for general-purpose amplifier and high-voltage switching applications, featuring V_CEO = −100 V, I_C = −200 mA, and h_FE ≥ 30 at −10 mA/−1 V; it operates across −55°C to +150°C and is commonly used in voltage-level translation and relay driver circuits.

For engineers reviewing the BSS63 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, SOT-23 package mapping, thermal derating guidance, saturation voltage behavior under defined drive conditions, and validated alternative transistors for discrete PNP switching and amplification roles.

Technical Context

The BSS63 is a silicon planar epitaxial PNP transistor fabricated using Fairchild's Process 74, optimized for stable DC gain and breakdown performance in low-power linear and saturated-switching modes. It supports continuous collector currents up to −200 mA with guaranteed h_FE ≥ 30 at −10 mA and −25 mA test points.

Its −100 V V_CEO rating enables use in higher-voltage bias networks and interface stages where NPN counterparts are unsuitable due to polarity constraints; f_T = 50 MHz at −25 mA/−5 V confirms suitability for audio-frequency amplification and moderate-speed digital switching.

Key Specifications

Pinout & Package

SOT-23 (TO-236AB) 3-lead surface-mount package with gull-wing leads; compact 2.92 mm × 1.30 mm footprint and 1.20 mm max height; marked "T3" on top surface.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose amplifier applications.

Compared with MMBT63, the BSS63 shares identical silicon and performance but uses legacy Fairchild marking; versus BC807-40, the BSS63 trades higher h_FE for significantly greater V_CEO, making it preferable in industrial and telecom interface applications where voltage headroom is critical.

Availability

BSS63 is available at Aetrix Electronics and suitable for relay driver circuits, level translation interfaces, audio preamplifier stages, and power supply enable control requiring stable component supply and long-lifecycle support.

Supply support for BSS63 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 is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BSS63 belongs to ON Semiconductor's discrete bipolar transistor product line, originally developed by Fairchild for robust, cost-effective PNP switching and amplification in space- and voltage-constrained applications.

FAQ

What is the maximum collector-emitter voltage rating for the BSS63?

The BSS63 has a guaranteed V_CEO rating of −100 V at T_A = 25°C, meaning it can safely block up to 100 V in reverse polarity across collector and emitter terminals when the base is open. This rating is based on a maximum junction temperature of 150°C and applies to continuous DC operation; pulsed conditions require consultation with ON Semiconductor for validation. The BSS63 maintains this rating across its full specified temperature range.

Is the BSS63 pin-compatible with the MMBT63?

Yes, the BSS63 and MMBT63 are electrically and physically identical: both use the SOT-23 package with emitter-base-collector pinout (1-2-3), share identical absolute maximum ratings, thermal characteristics, and electrical specifications. The MMBT63 is ON Semiconductor's standardized replacement nomenclature post-Fairchild integration; the BSS63 retains the original Fairchild marking "T3". No PCB changes are required when substituting either part.

What is the typical DC current gain (h_FE) of the BSS63 at operating conditions?

The BSS63 guarantees h_FE ≥ 30 at two test conditions: I_C = −10 mA with V_CE = −1.0 V, and I_C = −25 mA with V_CE = −1.0 V. These values are minimums-not typicals-and represent worst-case production lot performance. Actual h_FE may be higher, but circuit design must rely on the guaranteed minimum to ensure functionality across all units. The BSS63 does not specify a typical h_FE value in its official datasheet.

Can the BSS63 be used in linear amplifier applications?

Yes, the BSS63 is explicitly characterized for linear amplifier use, with published f_T = 50 MHz at I_C = −25 mA and V_CE = −5.0 V, and typical pulsed current gain curves across temperature. Its stable h_FE, low V_CE(sat), and −100 V breakdown support common-emitter and emitter-follower configurations in audio and sensor signal chains. However, designers must verify thermal limits and bias stability for each specific linear application, as the BSS63 is not optimized for ultra-low noise or RF performance.

What is the thermal resistance (R_θJA) of the BSS63 in standard mounting conditions?

The BSS63 has a specified R_θJA of 357°C/W when mounted on a standard FR-4 PCB measuring 40 mm × 40 mm × 1.5 mm, per JEDEC JESD51-3. This value reflects junction-to-ambient thermal resistance under natural convection; actual thermal performance depends on board layout, copper area, airflow, and nearby heat sources. Derating is 2.8 mW/°C above 25°C ambient, meaning maximum allowable power drops linearly as ambient temperature rises-critical for reliability in enclosed or high-temperature environments where the BSS63 operates.