Taiwan Semiconductor Corporation SF34G

Overview

SF34G from Taiwan Semiconductor is a 200 V, 3 A super fast recovery rectifier diode in DO-201AD package, featuring 35 ns reverse recovery time, 0.95 V forward voltage at 3 A and 25°C, and 125 A surge capability - used in high-efficiency DC-DC converters and switching inverters.

For engineers reviewing the SF34G datasheet, SF34G pinout, SF34G application, or SF34G equivalent, key selection criteria include V_RRM = 200 V, I_F = 3 A, t_rr = 35 ns, V_F = 0.95 V, and thermal resistance R_θJL = 10 °C/W - critical for thermal design and switching loss optimization in power supplies.

Technical Context

The SF34G is a single-die, planar junction silicon rectifier optimized for high-frequency switching applications. Its 35 ns reverse recovery time and low 0.95 V forward voltage at rated current enable reduced conduction and switching losses in SMPS topologies.

Rated for 200 V repetitive peak reverse voltage and 125 A non-repetitive surge (8.3 ms half-sine), it operates across –55°C to +150°C junction temperature with R_θJL = 10 °C/W and R_θJA = 35 °C/W - supporting compact heatsinkless designs in space-constrained converters.

Key Specifications

Pinout & Package

Package: DO-201AD - axial-leaded, molded plastic case with cathode band marking; RoHS-compliant, halogen-free, UL 94V-0 rated compound; pure tin-plated leads, J-STD-002 solderable.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar super fast rectifier applications.

Compared with STTH3L06S and ES3D, the SF34G offers optimal balance of 200 V rating, 35 ns recovery, and 0.95 V forward drop in a cost-optimized DO-201AD package - making it ideal for mid-voltage industrial and telecom power supplies where voltage margin and thermal efficiency are tightly constrained.

Availability

SF34G is available at Aetrix Electronics and suitable for DC-DC converters, switching inverters, and freewheeling applications requiring stable component supply, consistent parametric performance, and long-term industrial lifecycle support.

Supply support for SF34G 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and power semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in rectifiers, TVS, MOSFETs, and bipolar transistors since 1979.

The SF34G belongs to TSC's SF3xG super fast rectifier family, designed specifically for high-frequency, high-reliability power conversion in industrial, telecom, and automotive auxiliary power supplies.

FAQ

What is the maximum junction temperature rating for the SF34G?

The SF34G has a maximum junction temperature (T_J) of +150°C and a storage temperature range of –55°C to +150°C. This rating allows reliable operation in enclosed industrial enclosures and under-hood automotive environments when mounted on adequate PCB copper area. Thermal design must ensure actual T_J remains below 150°C under worst-case ambient and load conditions - the SF34G datasheet specifies R_θJL = 10 °C/W for lead-to-junction heat transfer.

Is the SF34G AEC-Q101 qualified?

The base SF34G is not AEC-Q101 qualified; however, the variant SF34GH is explicitly qualified per AEC-Q101 Rev D for automotive applications. The "H" suffix denotes qualification, including stress testing for temperature cycling, humidity, and mechanical shock. For automotive designs requiring qualification, specify SF34GH - it shares identical electrical parameters and DO-201AD packaging with the SF34G but adds full automotive reliability documentation and traceability.

What is the reverse recovery time test condition for the SF34G?

The SF34G reverse recovery time (t_rr) of 35 ns is measured under standardized conditions: forward current I_F = 0.5 A, reverse current I_R = 1.0 A, and reverse recovery current I_rr = 0.25 A. These conditions reflect typical commutation behavior in hard-switched converters. The value is guaranteed maximum - actual t_rr may be lower depending on circuit dV/dt and temperature, but system design should use 35 ns for worst-case timing analysis.

How does the SF34G compare to standard fast recovery diodes like FR304?

The SF34G delivers significantly faster switching than standard fast recovery diodes such as FR304 (t_rr ≈ 150 ns). With t_rr = 35 ns and V_F = 0.95 V, the SF34G reduces both switching loss and conduction loss in high-frequency SMPS. Unlike FR304, the SF34G also features tighter parameter distribution, AEC-Q101-qualified variants, and improved thermal resistance (R_θJL = 10 °C/W vs. ~15 °C/W for FR304), enabling more compact thermal design.

What is the cathode marking convention for the SF34G?

The SF34G uses a visible cathode band (typically white or silver) near one lead end to indicate the cathode terminal. Per DO-201AD mechanical specification, the banded end is the cathode; the opposite lead is the anode. This marking is laser-etched or molded into the epoxy body and aligns with JEDEC standards. Correct orientation is essential - reverse installation causes catastrophic failure under reverse bias due to V_RRM violation.