NXP Semiconductors BSN304,126

Overview

BSN304,126 from NXP Semiconductors (formerly Philips) is an N-channel enhancement-mode vertical D-MOS transistor in a TO-92 variant (SOT54) package, rated for 300 V drain-source voltage, 300 mA DC drain current, and 1 W total power dissipation at 25 °C ambient. It features low gate threshold (0.8–2 V), 3.7 Ω typical R_DS(on) at 250 mA/10 V, and fast switching (6–10 ns turn-on, 46–60 ns turn-off), enabling use as a line current interruptor in telephone sets and high-speed transformer drivers.

For engineers reviewing the BSN304,126 datasheet, BSN304,126 pinout, BSN304,126 application, or BSN304,126 equivalent, key selection considerations include its 300 V blocking capability, gate-drive compatibility with CMOS/TTL logic, thermal resistance of 125 K/W, and verified performance in relay driver and telecom line interface circuits.

Technical Context

The BSN304,126 employs a vertical D-MOS structure optimized for high-voltage switching with no secondary breakdown limitation. Its gate-source threshold voltage (0.8–2 V) ensures reliable turn-on with standard logic-level drive, while its 100 pF typical input capacitance and 21 pF output capacitance support stable high-speed operation up to 50 V supply rails.

Static characteristics are specified at T_j = 25 °C, with transfer admittance (Y_fs) ranging from 200 to 690 mS and drain-source leakage (I_DSS) ≤100 nA at 240 V. The device operates up to 150 °C junction temperature and exhibits predictable R_DS(on) temperature coefficient per Fig.12.

Key Specifications

Pinout & Package

BSN304,126 is housed in a plastic single-ended leaded through-hole TO-92 variant package (SOT54/SC-43), with 3 leads arranged on-circle. Mounting requires maximum lead length of 4 mm and a minimum 10 mm × 10 mm copper pad on the drain lead for thermal management.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel high-voltage switching applications.

Compared with BSN20,215 and BUK452-60R, the BSN304,126 uniquely balances 300 V capability, TO-92 mountability, and logic-level gate drive-making it optimal for space-constrained telecom line interface designs where voltage exceeds 60 V but remains below 400 V.

Availability

BSN304,126 is available at Aetrix Electronics and suitable for telephone line interface modules, relay driver boards, and line transformer driver circuits requiring stable component supply and long-term obsolescence management.

Supply support for BSN304,126 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

NXP Semiconductors is a global semiconductor leader formed from the spin-off of Philips Semiconductors in 2006, specializing in secure connectivity solutions for automotive, industrial, and communication markets.

The BSN304,126 belongs to NXP's legacy discrete power transistor family designed specifically for high-reliability telecom infrastructure and industrial control applications requiring robust 300 V switching in compact through-hole packages.

FAQ

What is the maximum drain-source voltage rating for the BSN304,126?

The BSN304,126 has a maximum drain-source voltage (V_DS) rating of 300 V DC, as defined in the Absolute Maximum Ratings table. This rating applies under standard mounting conditions (epoxy PCB, 4 mm lead length, 10 mm × 10 mm drain pad) and ensures safe operation in telephone line interruption and relay driving applications where transient voltages may reach 127 V peak. Exceeding 300 V risks permanent device failure.

Can the BSN304,126 be driven directly by a 3.3 V microcontroller GPIO?

Yes, the BSN304,126 can be driven directly by a 3.3 V microcontroller GPIO. Its gate-source threshold voltage (V_GS(th)) ranges from 0.8 V to 2.0 V, and its R_DS(on) drops to 4.8–10 Ω at V_GS = 2.4 V (per static characteristics). At 3.3 V, the device achieves full enhancement with low on-resistance, eliminating the need for external level-shifting circuitry in most low-current switching applications.

What is the thermal resistance junction-to-ambient for the BSN304,126?

The thermal resistance junction-to-ambient (R_{th j-a}) for the BSN304,126 is 125 K/W under specified mounting conditions: device mounted on an epoxy printed-circuit board with maximum lead length of 4 mm and a minimum 10 mm × 10 mm copper pad on the drain lead. This value assumes Tamb ≤ 25 °C and determines the maximum allowable power dissipation before junction temperature exceeds 150 °C.

Does the BSN304,126 have built-in protection against secondary breakdown?

Yes, the BSN304,126 is explicitly characterized as having no secondary breakdown limitation, as stated in its Features section. This means the device can safely switch inductive loads across its full voltage and current operating range without requiring SOA (Safe Operating Area) derating curves-unlike many bipolar transistors. This feature simplifies design validation for relay and transformer driver applications.

What package type is used for the BSN304,126?

The BSN304,126 uses a TO-92 variant package designated as SOT54 (also referenced as SC-43), a plastic single-ended leaded through-hole package with three leads arranged on-circle. Its mechanical outline matches JEDEC TO-92 but includes specific dimensional tolerances (e.g., L = 14.5 mm, D = 4.8 mm) confirmed in the Package Outlines section of the datasheet.