Taiwan Semiconductor Corporation UF1K

Overview

UF1K from Taiwan Semiconductor is a 800 V, 1 A high-efficiency glass-passivated fast recovery rectifier diode in DO-204AL (DO-41) package, featuring soft recovery, 75 ns reverse recovery time, and 1.7 V forward voltage at 1 A - used in DC-DC converters and freewheeling paths in industrial switching power supplies.

For engineers reviewing the UF1K datasheet, UF1K pinout, UF1K application, or UF1K equivalent, key selection criteria include repetitive peak reverse voltage (800 V), forward current rating (1 A), thermal resistance (R_θJL = 15 °C/W), soft recovery behavior, and AEC-Q101 qualification availability (UF1KH variant).

Technical Context

The UF1K is a single-die, planar passivated silicon PN junction rectifier optimized for high-frequency switching applications. Its soft recovery characteristic minimizes EMI generation during turn-off, and its 800 V V_RRM supports use in 400–600 V DC bus systems with margin.

Thermal performance is defined by R_θJL = 15 °C/W and R_θJA = 60 °C/W, enabling 1 A continuous conduction at ambient temperatures up to +75 °C on standard PCB layouts. Junction temperature is rated from –55 °C to +150 °C.

Key Specifications

Pinout & Package

Package: DO-204AL (DO-41), axial leaded, glass-passivated silicon die, cathode indicated by band. Leads are pure tin-plated, J-STD-002 solderable, and meet JESD201 Class 2 whisker resistance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage fast recovery diode applications.

Compared with STTH1R08 and MUR108, the UF1K delivers identical electrical performance in a compact DO-41 package with optional AEC-Q101 qualification - making it optimal for space-constrained, thermally moderate, and automotive-grade designs requiring proven reliability.

Availability

UF1K is available at Aetrix Electronics and suitable for DC-DC converters, switching mode inverters, and freewheeling applications requiring stable component supply, consistent parametric binning, and long-term industrial lifecycle support.

Supply support for UF1K 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 discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving global industrial, computing, and automotive markets since 1979.

The UF1K belongs to TSC's UF1x ultra-fast recovery rectifier family, designed specifically for high-efficiency, high-frequency switching power conversion where soft recovery, thermal robustness, and reliability under thermal cycling are critical.

FAQ

What is the maximum repetitive peak reverse voltage (V_RRM) of the UF1K?

The UF1K has a maximum repetitive peak reverse voltage (V_RRM) of 800 V, as specified in the absolute maximum ratings table. This value is confirmed across all official documentation versions (G2104) and defines the highest reverse voltage the device can block repeatedly without breakdown. The UF1K's 800 V rating makes it suitable for 400 V AC input rectification and 600 V DC bus clamp applications. This parameter is fixed for the UF1K and differs from other members of the UF1x series such as UF1J (600 V) and UF1M (1000 V).

Does the UF1K have AEC-Q101 qualification?

The base UF1K part is not AEC-Q101 qualified; however, the UF1KH variant - which shares identical electrical and thermal specifications - is explicitly qualified per AEC-Q101. The "H" suffix denotes automotive qualification, including stress testing for temperature cycling, humidity, and mechanical shock. For automotive applications requiring formal qualification, designers must specify UF1KH, not UF1K. Both variants use the same DO-41 package and marking layout, differing only in test documentation and traceability.

What is the forward voltage (V_F) of the UF1K at 1 A and 25 °C?

The UF1K has a maximum forward voltage (V_F) of 1.7 V at 1 A forward current and 25 °C junction temperature, as stated in the Electrical Specifications table. This value is measured under pulsed conditions (PW = 0.3 ms) to avoid self-heating effects. At elevated temperatures (e.g., 125 °C), V_F decreases slightly due to semiconductor physics, but system-level thermal design must still account for ~1.7 W conduction loss at full load under ambient conditions.

What is the reverse recovery time (t_rr) of the UF1K, and how is it tested?

The UF1K has a maximum reverse recovery time (t_rr) of 75 ns, measured under conditions of I_F = 0.5 A, I_R = 1.0 A, and I_rr = 0.25 A, per the test circuit shown in Figure 6 of the datasheet. This soft-recovery behavior reduces switching noise and voltage overshoot in high-frequency converters. The 75 ns value applies specifically to UF1J/UF1K/UF1M variants; lower-voltage variants (e.g., UF1A–UF1G) are rated at 50 ns.

What package type does the UF1K use, and what are its mechanical features?

The UF1K uses the DO-204AL (DO-41) axial-leaded package, with glass-passivated chip junction, pure tin-plated leads compliant with J-STD-002, and UL 94V-0 molding compound. Polarity is marked by a cathode band, and typical weight is 0.330 g. The package supports both tape-and-reel (5,000 pcs) and ammo box (3,000 pcs) packaging options. Lead finish and whisker resistance meet JESD201 Class 2 requirements, ensuring long-term solder joint integrity.