onsemi BCX71JLT1

Overview

BCX71JLT1 from onsemi is a PNP silicon general-purpose transistor in SOT-23 package, rated for −45 V V_CEO, −100 mA I_C, and 350 mW power dissipation at 25°C. It delivers h_FE = 40–460 (at I_C = 2.0 mA, V_CE = 5.0 V), V_CE(sat) ≤ −0.25 V (I_C = 10 mA, I_B = 0.25 mA), and C_obo = 6.0 pF, commonly used in low-power switching and signal amplification circuits.

For engineers reviewing the BCX71JLT1 datasheet, pinout, applications, or equivalent options, key selection criteria include its PNP polarity, SOT-23 footprint compatibility, guaranteed h_FE range across operating currents, saturation voltage performance at defined drive conditions, and thermal derating profile for ambient-limited designs.

Technical Context

The BCX71JLT1 is a discrete bipolar junction transistor optimized for linear amplification and digital switching in low-voltage, low-current applications. Its design supports operation up to 150°C junction temperature with specified leakage (I_CES ≤ −20 nA at V_CE = 32 V, 25°C; ≤ −20 A at 150°C) and noise figure ≤ 6.0 dB (I_C = 0.2 mA, R_S = 2.0 kΩ, 1 kHz).

It features a fixed-emitter configuration with base-driven control, exhibits f_T ≈ 200 MHz at I_C = −1.0 mA (V_CE = −20 V), and maintains stable h_FE across −55°C to +125°C with documented temperature coefficients for V_BE(on) and h_FE.

Key Specifications

Pinout & Package

SOT-23 (TO-236) surface-mount package per CASE 318-08, 3-pin, moisture sensitivity level 1, Pb-free compatible. Dimensions: 2.90 mm × 1.30 mm × 1.00 mm (L × W × H), 0.65 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BCX71JLT1, BC807-40LT1G offers higher current capability and tighter h_FE distribution but requires layout verification for thermal handling at full 500 mA; MMBT3906LT1G trades 5 V breakdown margin and 1.5 dB higher noise for broader distributor availability and lower unit cost in high-volume production.

Availability

BCX71JLT1 is available at Aetrix Electronics and suitable for audio pre-amplifiers, logic level shifters, LED drivers, and power supply enable circuits requiring stable component supply, consistent h_FE binning, and SOT-23 footprint compatibility.

Supply support for BCX71JLT1 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, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BCX71JLT1 belongs to onsemi's general-purpose bipolar transistor product line, designed for cost-sensitive, space-constrained applications requiring reliable DC amplification and switching performance across extended temperature ranges.

FAQ

What is the maximum continuous collector current rating for BCX71JLT1?

The BCX71JLT1 has a maximum continuous collector current (I_C) rating of −100 mA at T_A = 25°C. This rating decreases with rising ambient temperature due to thermal derating of 2.8 mW/°C above 25°C, and actual usable current depends on PCB copper area, airflow, and mounting substrate. The BCX71JLT1 must not exceed its 350 mW total power dissipation limit under any operating condition.

Does BCX71JLT1 support Pb-free soldering processes?

Yes, BCX71JLT1 is offered in a Pb-free package compliant with RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level 1. The device supports standard reflow profiles including peak temperatures up to 260°C for 10 seconds, and its SOT-23 package is qualified for both leaded and lead-free assembly per onsemi's Soldering and Mounting Techniques Reference Manual.

What is the typical noise figure of BCX71JLT1 and under what conditions is it measured?

The BCX71JLT1 has a maximum noise figure (NF) of 6.0 dB, measured at I_C = 0.2 mA, V_CE = −5.0 V, R_S = 2.0 kΩ, f = 1.0 kHz, and bandwidth = 200 Hz. This value reflects input-referred noise performance in low-level analog amplification; actual NF varies with operating point and source impedance, as shown in Figures 3–5 of the official BCX71J/D datasheet.

Can BCX71JLT1 be used as a direct replacement for BC857 in SOT-23 designs?

No, BCX71JLT1 is not a direct replacement for BC857. While both are PNP SOT-23 transistors, BC857 specifies V_CEO = −45 V and h_FE = 125–800, whereas BCX71JLT1 has h_FE = 40–460 and different saturation characteristics. Layout reuse is possible, but circuit validation-including base resistor recalculations and thermal assessment-is required before substitution. The BCX71JLT1 datasheet does not claim pin compatibility or functional equivalence with BC857.

What are the absolute maximum ratings for base-emitter voltage on BCX71JLT1?

The absolute maximum emitter-base voltage (V_EBO) for BCX71JLT1 is −5.0 Vdc, defined as the reverse-bias voltage beyond which irreversible junction damage may occur. This rating applies with the collector open (I_C = 0). Exceeding −5.0 V-even briefly-risks permanent degradation of h_FE and increased leakage. The BCX71JLT1 must be biased such that V_EB remains within this limit during all operational and transient states.