onsemi BC858CMTF

Overview

BC858CMTF from ON Semiconductor is a PNP epitaxial silicon transistor in SOT-23 package, rated for V_CEO = −30 V, I_C = −100 mA, and h_FE = 420–800 (Class C), with low V_CE(sat) of −250 mV at I_C = −10 mA / I_B = −0.5 mA, used in low-noise amplifier and switching stages of portable power management circuits.

For engineers reviewing the BC858CMTF datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, validated SOT-23 terminal mapping, confirmed noise performance (NF = 2 dB @ 1 kHz), and direct alternatives for discrete PNP gain-stage replacement in space-constrained analog and digital interface designs.

Technical Context

The BC858CMTF operates as a general-purpose PNP bipolar junction transistor optimized for linear amplification and saturated switching in low-voltage DC circuits. Its h_FE classification (C: 420–800) ensures consistent current gain across production lots, while its f_T = 150 MHz supports audio-frequency signal conditioning and fast-switching logic interfacing.

Thermal design is enabled by T_J = 150°C maximum junction temperature and P_C = 310 mW power dissipation in SOT-23. The device exhibits low output capacitance (C_ob = 6 pF @ V_CB = −10 V), minimizing high-frequency loading in RF-coupled bias networks.

Key Specifications

Pinout & Package

SOT-23 plastic surface-mount package with gull-wing leads; 1.90 mm × 1.30 mm footprint, 1.14 mm max height, and JEDEC-compliant thermal pad layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC858CMTF, BC857CMTF offers higher voltage tolerance at minor saturation penalty, while MMBT3906LT1G trades gain precision and noise performance for broader commercial availability-making BC858CMTF optimal for noise-sensitive, gain-critical PNP roles in compact PCB layouts.

Availability

BC858CMTF is available at Aetrix Electronics and suitable for portable audio pre-amplifiers, industrial level-shifting interfaces, and LED driver switches requiring stable component supply, consistent h_FE binning, and low-noise analog performance.

Supply support for BC858CMTF 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, and discrete components for automotive, industrial, and consumer applications.

The BC858CMTF belongs to ON Semiconductor's legacy general-purpose transistor family, designed specifically for high-reliability, low-cost discrete amplification and switching in space-constrained PCBs.

FAQ

What is the guaranteed h_FE range for BC858CMTF?

The BC858CMTF is classified as Class C, with a guaranteed DC current gain (h_FE) of 420 to 800 when measured at V_CE = −5 V and I_C = −2 mA. This tight gain spread ensures predictable base drive requirements and simplifies bias network design without post-production trimming. The BC858CMTF specification sheet confirms this range applies to every unit shipped in tape-and-reel format.

Does BC858CMTF support low-noise audio applications?

Yes, BC858CMTF has a specified noise figure of 2 dB at V_CE = −5 V, I_C = −200 µA, R_G = 2 kΩ, and f = 1 kHz-verified in the official Fairchild/ON Semiconductor datasheet. This makes BC858CMTF suitable for microphone pre-amplifier stages and sensor signal conditioning where sub-3 dB noise is required, unlike standard PNP transistors with NF > 4 dB.

What is the maximum power dissipation for BC858CMTF in SOT-23?

The BC858CMTF has a maximum collector power dissipation (P_C) of 310 mW at T_A = 25°C, as defined in its absolute maximum ratings table. Derating is required above 25°C ambient-approximately 2.48 mW/°C-so at 70°C ambient, usable power drops to ~200 mW. This value is confirmed for the SOT-23 package with standard PCB copper land patterns.

Is BC858CMTF pin-compatible with other BC8xx series transistors?

Yes, BC858CMTF uses the standard SOT-23 pinout (1: Base, 2: Emitter, 3: Collector), matching all BC856–BC860 variants including BC857CMTF and BC859CMTF. Mechanical and electrical compatibility is maintained across the family, enabling drop-in substitution where voltage and gain requirements align-though V_CEO and V_CBO differ between subtypes.

What does the "TF" suffix indicate in BC858CMTF?

The "TF" suffix in BC858CMTF denotes tape-and-reel packaging, with 3000 units per reel, as specified in the ordering information table. This format is optimized for automated SMT placement equipment and is distinct from bulk or cut-tape options. The marking "9CC" on the device body further identifies it as the Class C h_FE variant in SOT-23.