Diodes Incorporated UF1505S-B

Overview

UF1505S-B from Diodes Incorporated is a 1.5A ultra-fast rectifier diode in DO-41 package, rated for 600V peak repetitive reverse voltage (V_RRM), 1.7V forward voltage at 1.5A (V_FM), and 50ns reverse recovery time (t_rr), deployed in offline AC/DC power supplies and switch-mode PFC stages.

For engineers reviewing the UF1505S-B datasheet, UF1505S-B pinout, UF1505S-B application, or UF1505S-B equivalent, key selection criteria include V_RRM=600V, I_O=1.5A @ T_A=50°C, t_rr=50ns, low I_RM=5.0µA @ 25°C, and DO-41 mechanical compatibility with high-reliability industrial power converters.

Technical Context

This discrete ultra-fast rectifier uses a diffused junction structure to achieve rapid carrier recombination, enabling efficient operation in 20–100kHz SMPS output stages where reverse recovery loss must be minimized. Its 50ns t_rr and 1.7V V_FM balance conduction and switching losses under 1.5A DC load conditions.

The device supports surge immunity up to 50A (8.3ms half-sine) and maintains low reverse leakage (5.0µA @ 25°C, 100µA @ 100°C) across its –65°C to +150°C operating range, making it suitable for thermally constrained board-level rectification in enclosed power adapters.

Key Specifications

Pinout & Package

DO-41 axial-leaded plastic package (UL 94V-0), 0.35g mass, cathode indicated by band; leads tin-plated, solderable per MIL-STD-202 Method 208.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STTH1L06U and ES1J, UF1505S-B delivers optimal balance of 1.5A current capability, 50ns speed, and DO-41 manufacturability-making it the default choice for cost-sensitive, thermally moderate 600V rectification where 100% I_O utilization is needed.

Availability

UF1505S-B is available at Aetrix Electronics and suitable for AC/DC adapters, industrial SMPS units, LED drivers, and PFC boost circuits requiring stable component supply, consistent DO-41 form factor, and verified 600V/1.5A performance.

Supply support for UF1505S-B 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and the US.

The UF150xS series targets high-efficiency, cost-optimized power conversion in consumer and industrial power supplies, emphasizing ultra-fast recovery, robust surge tolerance, and RoHS-compliant DO-41 packaging.

FAQ

What is the maximum allowable junction temperature for UF1505S-B?

The absolute maximum junction temperature is +150°C, with continuous operation permitted from –65°C to +150°C. Derating begins at T_A = 50°C per Figure 1; at 70°C ambient, I_O must be reduced to 1.1A to maintain T_J ≤ 150°C given R_θJA = 70°C/W.

Can UF1505S-B replace UF1504S in a 400V design?

Yes - UF1505S-B has V_RRM = 600V versus UF1504S's 400V, providing 50% higher reverse voltage margin. No layout or thermal changes are needed, as both share identical DO-41 package, pinout, and thermal resistance (R_θJA = 70°C/W).

Is UF1505S-B suitable for synchronous rectification?

No - UF1505S-B is a passive silicon PN-junction diode, not a MOSFET-based synchronous rectifier. It lacks gate control and cannot be actively switched; it functions only as a unidirectional, self-commutating rectifier in conventional topologies.

How does the 50ns reverse recovery time impact EMI in a 65kHz flyback converter?

At 65kHz, the 50ns t_rr limits reverse recovery di/dt, reducing high-frequency ringing amplitude by ~8dB compared to 200ns diodes. This directly lowers common-mode noise coupling into Y-capacitors and eases compliance with CISPR-32 Class B conducted emissions limits.