onsemi PN3568

Overview

PN3568 from Fairchild Semiconductor is an NPN general-purpose bipolar junction transistor (BJT) designed for medium-power amplification and switching applications up to 500mA collector current. It features V_CEO = 60 V, V_CBO = 80 V, h_FE = 40–120 at I_C = 30–150 mA, V_CE(sat) = 0.25 V, and operates across –55°C to +150°C junction temperature range - used in DC-DC converter control stages and audio preamplifier circuits.

For engineers reviewing the PN3568 datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-92 package compatibility, guaranteed h_FE spread, low V_CE(sat) at 150 mA drive, thermal resistance (R_θJA = 200°C/W), and suitability for linear amplification versus saturated switching roles.

Technical Context

The PN3568 is a silicon NPN BJT optimized for general-purpose analog amplification and medium-current switching. Its design supports continuous I_C up to 1.0 A with derating above 25°C, and exhibits stable h_FE over I_C = 30–150 mA at V_CE = 1.0 V. Breakdown voltages (V_(BR)CEO = 60 V, V_(BR)CBO = 80 V) define safe operating area boundaries under open-base and open-emitter conditions.

Thermal performance is characterized by R_θJA = 200°C/W and R_θJC = 83.3°C/W, enabling operation up to +150°C junction temperature when mounted on standard PCBs without heatsinking. Small-signal parameters include h_fe = 3.0–30 at f = 20 MHz and C_ob = 20 pF at V_CB = 10 V, supporting mid-frequency amplifier designs.

Key Specifications

Pinout & Package

PN3568 is housed in a through-hole TO-92 package with standardized lead configuration: Emitter (Pin 1), Base (Pin 2), Collector (Pin 3). The package provides mechanical robustness and solderability for prototyping and low-volume production.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC547B and MPSA18, PN3568 offers superior voltage margin (60 V) and proven thermal robustness (150°C T_J) for industrial switching, while maintaining TO-92 compatibility and predictable DC gain - making it preferred for cost-sensitive, medium-power linear and saturated applications where reliability across temperature is critical.

Availability

PN3568 is available at Aetrix Electronics and suitable for DC-DC converter switches, audio preamplifier stages, relay driver circuits, and LED current regulators requiring stable component supply and long-term industrial availability.

Supply support for PN3568 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016. Its legacy products remain widely deployed in industrial and consumer systems.

PN3568 belongs to Fairchild's general-purpose NPN transistor product line, engineered for cost-effective, thermally resilient amplification and switching in non-critical industrial and consumer electronics where TO-92 form factor and predictable DC characteristics are prioritized.

FAQ

What is the maximum continuous collector current rating for PN3568?

The PN3568 is rated for 1.0 A continuous collector current at T_A = 25°C, with linear derating of 5.0 mW/°C above that ambient temperature. This rating assumes proper PCB copper area and no additional heatsinking. At 75°C ambient, the effective power limit drops to ~375 mW, corresponding to approximately 600 mA continuous I_C under typical V_CE(sat) conditions. Always verify junction temperature using R_θJA = 200°C/W in final layout.

Does PN3568 have a specified h_FE range at higher collector currents?

Yes, the PN3568 datasheet specifies h_FE = 40 minimum and 120 maximum at two test points: V_CE = 1.0 V, I_C = 30 mA and V_CE = 1.0 V, I_C = 150 mA. This confirms usable gain remains within specification across a 5× current range, supporting both small-signal amplification and medium-current switching without gain collapse.

Can PN3568 be used in linear regulator applications?

Yes, PN3568 can serve as a pass transistor in low-dropout linear regulators where I_OUT ≤ 500 mA and dropout voltage ≤ 1.5 V. Its V_BE(on) = 1.1 V and h_FE stability support predictable base drive design. However, thermal limits (P_D = 625 mW at 25°C) require careful power dissipation calculation - e.g., at 500 mA and 1.0 V dropout, 500 mW must be safely dissipated via PCB copper or limited duty cycle.

What is the pin configuration for PN3568 in TO-92 package?

PN3568 uses standard TO-92 pinout: Pin 1 is Emitter, Pin 2 is Base, Pin 3 is Collector - verified per Fairchild's November 2002 Rev. B datasheet and package outline drawing. When viewing the flat side of the TO-92 with leads pointing downward, pins are numbered left-to-right as 1–2–3. This matches JEDEC TO-92 orientation and ensures compatibility with standard sockets and footprints.

Is PN3568 suitable for automotive under-hood applications?

PN3568 supports junction temperatures up to +150°C and operates from –55°C, meeting extended temperature requirements for many automotive under-hood locations. However, it is not AEC-Q101 qualified, and Fairchild's datasheet does not specify automotive-grade screening or PPAP documentation. For production automotive use, PN3568 should undergo customer-specific qualification; it is appropriate for prototyping, aftermarket modules, or non-safety-critical subsystems where full qualification is not mandated.