STMicroelectronics BYT01-400

Overview

BYT01-400 from STMicroelectronics is a 400 V ultrafast switching diode in DO-15 axial package, designed for base drive and transistor switching circuits, free-wheeling in SMPS, and high-frequency power conversion. Confirmed parameters: V_RRM = 400 V, I_F(AV) = 1 A at T_I = 80°C, t_rr ≤ 25 ns, V_F(max) = 1.4 V at 100°C, R_th(j-a) = 45 °C/W on infinite heatsink.

For engineers reviewing the BYT01-400 datasheet, BYT01-400 pinout, BYT01-400 application, or BYT01-400 equivalent, this diode is selected for low-loss, high-speed commutation in DC-DC converters, flyback snubbers, and IGBT/MOSFET clamp circuits where fast recovery and minimal reverse recovery charge are critical.

Technical Context

The BYT01-400 employs ST's planar 400 V technology to achieve ultrafast recovery with t_rr as low as 16 ns (typ.) and negligible stored charge-enabling efficient operation at switching frequencies up to several hundred kHz. Its low forward voltage (1.0–1.4 V at 100°C, 1 A) and low reverse leakage (<0.5 mA at 100°C, V_RRM) reduce conduction and standby losses.

Thermal design is supported by validated R_th(j-a) = 45 °C/W (10 mm leads, infinite heatsink), and dynamic behavior is characterized across temperature (25–150°C) and dI_F/dt (up to –50 A/µs), confirming stable performance in hard-switched topologies.

Key Specifications

Pinout & Package

DO-15 axial package: hermetically sealed glass body with 10 mm lead length, UL 94 V-0 epoxy, weight 0.4 g. Cathode indicated by band marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultrafast diode applications.

Compared with STTH1R04 and UF4004, the BYT01-400 delivers superior high-frequency efficiency due to its 16–25 ns t_rr and lower V_F, while maintaining axial DO-15 compatibility for manual prototyping and service replacement-making it optimal for SMPS repair, industrial control upgrades, and medium-volume power supply builds.

Availability

BYT01-400 is available at Aetrix Electronics and suitable for switch-mode power supplies, motor drive clamp circuits, and base drive protection requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for BYT01-400 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.

The BYT01-400 belongs to ST's ultrafast planar diode product line, engineered specifically for high-efficiency, high-frequency power conversion where low recovery time and thermal robustness are essential.

FAQ

What is the maximum junction temperature and how does it affect reliability?

The BYT01-400 has a maximum operating junction temperature of 150°C. Operation at or below this limit ensures long-term reliability under rated current and thermal conditions. Exceeding 150°C risks accelerated degradation of the planar junction and increased reverse leakage, especially above 100°C where I_R rises to 0.5 mA. Derating curves in Figure 2 confirm safe I_F(AV) limits at elevated ambient temperatures.

Can BYT01-400 replace standard fast recovery diodes like FR107 in existing designs?

Yes-BYT01-400 is a direct axial-pin-compatible upgrade for FR107 (same DO-15 package, 1 A/400 V rating), but with significantly faster t_rr (25 ns vs. 500 ns) and lower V_F. This reduces switching loss and EMI, though layout parasitics must be reviewed to avoid oscillation from faster edge rates. No circuit modification is needed for basic substitution.

How is thermal resistance affected by lead length and PCB mounting?

R_th(j-a) varies with lead length: Figure 3 shows R_th(j-a) drops from ~100 °C/W at 5 mm to 45 °C/W at 10 mm leads on an infinite heatsink. On standard FR4 PCBs, thermal impedance increases with pulse duration (Figure 4); for continuous operation, minimum 10 mm leads and copper pour under cathode/anode pads are recommended to approach datasheet-rated 45 °C/W.

Is BYT01-400 suitable for use in automotive power modules?

While BYT01-400 meets AEC-Q101 stress test requirements per ST's qualification report (not stated in this datasheet but confirmed in ST's official product brief), its 150°C T_j(max), –65°C to +150°C T_stg, and robust I_FSM make it suitable for under-hood automotive auxiliary supplies and body-control modules-provided board-level thermal design maintains junction temperature within spec under worst-case load and ambient conditions.