onsemi BC859CLT1G

Overview

BC859CLT1G from onsemi is a PNP silicon general-purpose transistor in SOT-23 package, rated for V_CEO = −30 V, I_C = −100 mA continuous, and h_FE = 420–800 (at I_C = −2.0 mA, V_CE = −5.0 V). It delivers low V_CE(sat) = −0.3 V (at I_C = −10 mA, I_B = −0.5 mA) and f_T = 100 MHz, enabling use in compact signal switching and amplification stages of industrial control interfaces.

For engineers reviewing the BC859CLT1G datasheet, pinout, applications, or equivalent options, key selection criteria include its −30 V V_CEO, high-current-gain bin (C-grade), SOT-23 footprint compatibility, AEC-Q101 qualification status, and verified noise performance (NF = 4.0 dB at 1 kHz).

Technical Context

The BC859CLT1G operates as a discrete PNP bipolar junction transistor with fixed emitter-base and collector-base junction structures optimized for linear amplification and saturated switching. Its h_FE binning (C-grade: 420–800) ensures consistent current gain across production lots, while the −30 V V_CEO and −30 V V_CBO ratings define safe operating limits under reverse-biased conditions in low-voltage DC bias networks.

Thermal design relies on R_JA = 556 °C/W (FR-5 board) or 417 °C/W (alumina substrate), with PD = 225 mW (derated above 25°C at 1.8 mW/°C) establishing power handling boundaries. Switching behavior is characterized by t_d = 35 ns, t_r = 25 ns, t_s = 310 ns, and t_f = 40 ns under −3.0 V V_CC, −10 mA I_C, −1 mA I_E test conditions.

Key Specifications

Pinout & Package

SOT-23 (TO-236) surface-mount package, 2.90 mm × 1.30 mm × 1.00 mm body size, 1.90 mm lead pitch, JEDEC MO-215 compliant. RoHS-compliant, Pb-free construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC859CLT1G, BC857CLT1G offers higher voltage tolerance without sacrificing gain or noise, while BC858CLT1G trades guaranteed high h_FE for broader availability and lower unit cost-making it viable where gain variation is acceptable.

Availability

BC859CLT1G is available at Aetrix Electronics and suitable for industrial sensor interfaces, automotive body control modules, and consumer audio preamplifier stages requiring stable component supply, long-term lifecycle support, and AEC-Q101 compliance.

Supply support for BC859CLT1G 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The BC859CLT1G belongs to the BC856ALT1G Series of general-purpose PNP transistors designed for reliable, cost-effective signal amplification and switching in space-constrained, high-reliability applications across automotive and industrial segments.

FAQ

What is the maximum collector-emitter voltage rating for BC859CLT1G?

The BC859CLT1G has a maximum collector-emitter voltage (V_CEO) rating of −30 V at T_A = 25°C. This rating applies under continuous DC conditions and defines the upper limit for safe operation in common-emitter configurations. Exceeding this voltage risks avalanche breakdown and permanent device damage, especially at elevated temperatures where derating is required per the datasheet's thermal characteristics table.

Is BC859CLT1G suitable for automotive applications?

Yes, BC859CLT1G is AEC-Q101 qualified and PPAP capable, making it suitable for automotive applications such as body control modules, lighting drivers, and sensor signal conditioning. Its guaranteed h_FE binning, −55°C to +150°C operating temperature range, and robust thermal performance (R_JA = 556 °C/W on FR-5 board) meet stringent automotive reliability requirements without requiring additional qualification testing.

What does the "C" suffix in BC859CLT1G indicate?

The "C" in BC859CLT1G denotes the h_FE gain bin: minimum h_FE = 420, typical = 520, maximum = 800 at I_C = −2.0 mA and V_CE = −5.0 V. This high-gain bin ensures predictable current amplification in low-base-drive circuits like sensor interfaces and audio preamps, distinguishing it from "A" (125–250) and "B" (220–475) variants in the same family.

What is the thermal resistance of BC859CLT1G on a standard FR-5 PCB?

The BC859CLT1G has a junction-to-ambient thermal resistance (R_JA) of 556 °C/W when mounted on an FR-5 board (1.0 × 0.75 × 0.062 in), with total device dissipation (P_D) rated at 225 mW at T_A = 25°C. Derating is required at 1.8 mW/°C above 25°C, meaning usable power drops to ~135 mW at 80°C ambient-critical for thermal design in enclosed enclosures.

Does BC859CLT1G have the same pinout as other SOT-23 transistors?

Yes, BC859CLT1G uses Style 6 pinout per onsemi's SOT-23 mechanical drawings: Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector. This matches industry-standard PNP SOT-23 assignments and ensures compatibility with existing footprints for BC856/857/858 series devices, simplifying board reuse and second-source qualification without layout changes.