onsemi BC808-25LT1

Overview

BC808-25LT1 from onsemi is a PNP silicon general-purpose transistor in SOT-23 package, rated for −25 V V_CEO, −500 mA I_C, and 225 mW power dissipation on FR-5 board; it delivers h_FE = 160–400 at I_C = −100 mA and supports switching and linear amplification in low-voltage DC control circuits.

For engineers reviewing the BC808-25LT1 datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CEO/I_C ratings, SOT-23 thermal derating behavior, h_FE consistency across I_C range, and Pb-free compliance per J-STD-609.

Technical Context

This discrete PNP bipolar junction transistor operates in active, saturation, and cutoff regions with defined breakdown limits: V_(BR)CEO = −25 V (I_C = −10 mA), V_(BR)EBO = −5.0 V (I_E = −1.0 A), and V_CE(sat) ≤ −0.7 V at I_C = −500 mA / I_B = −50 mA.

Its small-signal performance includes f_T = 100 MHz (I_C = −10 mA, V_CE = −5 V), C_obo = 10 pF (V_CB = −10 V), and thermal resistance R_JA = 556 °C/W on FR-5 board - confirming suitability for medium-speed switching below 50 MHz with moderate power handling.

Key Specifications

Pinout & Package

SOT-23 (TO-236) package, 3-pin surface-mount, JEDEC case 318, style 6. Dimensions: 2.90 mm × 1.30 mm × 1.00 mm (L × W × H), with 1.90 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC808-25LT1, BC807-25LT1 offers identical gain and voltage specs but one-fifth the current rating, limiting use to signal-level tasks; MMBT3906LT1G trades current capability for higher voltage tolerance and tighter h_FE distribution - both require revalidation of base drive and thermal design.

Availability

BC808-25LT1 is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO expansion, DC motor direction control, and power supply enable switching requiring stable component supply and Pb-free compliance.

Supply support for BC808-25LT1 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 focused on energy-efficient electronics, delivering silicon-based solutions for automotive, industrial, cloud, and IoT markets.

The BC808-25LT1 belongs to onsemi's general-purpose bipolar transistor product line, engineered for cost-sensitive, high-volume applications demanding reliable DC switching and linear amplification in compact SOT-23 form factor.

FAQ

What is the maximum continuous collector current for BC808-25LT1?

The BC808-25LT1 is rated for −500 mA continuous collector current (I_C) at T_A = 25°C on FR-5 board. Derating applies above 25°C at 1.8 mW/°C. This rating assumes proper PCB copper area and airflow; actual achievable current depends on thermal design and ambient conditions. The BC808-25LT1 must not exceed this limit to avoid permanent degradation or thermal runaway.

Does BC808-25LT1 have Pb-free packaging?

Yes, BC808-25LT1 is offered in a Pb-free SOT-23 package compliant with J-STD-609 Class 3 and RoHS Directive 2011/65/EU. The "LT1" suffix denotes tape-and-reel packaging, and the "G" variant (BC808-25LT1G) explicitly confirms Pb-free finish. Standard BC808-25LT1 units shipped by onsemi since 2005 meet Pb-free requirements unless otherwise specified in order documentation.

What is the DC current gain (h_FE) range for BC808-25LT1 at typical operating conditions?

The BC808-25LT1 exhibits h_FE = 160–400 when tested at I_C = −100 mA and V_CE = −1.0 V, TA = 25°C. At higher current (I_C = −500 mA), h_FE drops to ≥40. This wide gain spread means base resistors must be sized for the minimum h_FE to ensure saturation across process and temperature variation. The BC808-25LT1 data sheet guarantees these bounds across production lots.

Can BC808-25LT1 be used in switching applications up to 100 kHz?

Yes, BC808-25LT1 supports switching up to ~100 kHz in optimized designs due to its f_T = 100 MHz and fast turn-on/turn-off times (typical t_on ≈ 35 ns, t_off ≈ 200 ns per onsemi characterization). However, practical 100 kHz operation requires careful attention to base drive strength, load inductance, and layout parasitics. The BC808-25LT1 is not intended for RF or high-frequency resonant converters but performs well in PWM-controlled DC-DC and motor drives below 50 kHz.

What are the absolute maximum junction and storage temperatures for BC808-25LT1?

The BC808-25LT1 has an absolute maximum junction and storage temperature range of −55°C to +150°C. Operation beyond this range risks irreversible damage to the silicon die or bond wires. Thermal design must ensure T_J remains within limits under worst-case power dissipation - for example, at 225 mW PD on FR-5 board, ambient must stay below ~100°C to maintain T_J ≤ 150°C. The BC808-25LT1 specification strictly defines these boundaries in its thermal characteristics table.