Diodes Incorporated SD945-B

Overview

SD945-B from Diodes Incorporated is a high-current Schottky barrier rectifier in DO-201AD package, rated for 45 V peak reverse voltage, 9.0 A average forward current at TC = 120°C, and 340 A non-repetitive surge current. It delivers low forward voltage (0.52 V @ 9.0 A, TJ = 125°C) and features guard ring protection for transient immunity, used in high-efficiency AC/DC secondary-side rectification.

For engineers reviewing the SD945-B datasheet, SD945-B pinout, SD945-B application, or SD945-B equivalent, key selection criteria include its 45 V blocking rating, thermal resistance of 8.0 K/W (junction-to-lead), 900 pF junction capacitance at 4 V, RoHS-compliant tin-plated leads, and DO-201AD mechanical compatibility with high-power PCB mounting.

Technical Context

This device operates as a unidirectional power rectifier optimized for high-current, low-loss DC output stages. Its Schottky architecture enables fast switching (dv/dt = 10,000 V/µs), minimal reverse recovery charge, and operation up to +150°C junction temperature.

The DO-201AD package provides robust thermal conduction via lead-mounted heatsinking (RθJL = 8.0 K/W), while the cathode band polarity marking and 94V-0 flammability-rated molded plastic case support reliable industrial assembly and safety compliance.

Key Specifications

Pinout & Package

DO-201AD package: axial-leaded, molded plastic case with cathode band marking; 1.1 g mass; UL 94V-0 rated; moisture sensitivity level 1; tin-plated leads solderable per MIL-STD-202, Method 208.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-current Schottky rectifier applications.

Compared with VS-10BQ045 and SBRT10U45SP5, SD945-B offers identical electrical performance to the ON Semiconductor second source but trades 0.5 K/W higher thermal resistance for broader distributor stock depth and documented legacy field reliability in telecom power systems.

Availability

SD945-B is available at Aetrix Electronics and suitable for server power supply rectification, industrial DC power modules, telecom base station PSUs, and LED driver secondary rectification requiring stable component supply and long-term BOM continuity.

Supply support for SD945-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 and manufacturing operations across Asia and the US.

The SD9xx series belongs to Diodes' high-current Schottky rectifier product line, engineered specifically for efficiency-critical secondary-side rectification in AC/DC and DC/DC power supplies operating above 5 A output current.

FAQ

Is SD945-B pin-compatible with SD940-B and SD930-B?

Yes - all three share identical DO-201AD package, anode/cathode terminal configuration, and mechanical outline. The only differences are maximum ratings: SD945-B supports 45 V VRRM (vs. 40 V for SD940-B and 30 V for SD930-B), making it a direct upgrade in designs where higher reverse margin is needed without layout change.

What is the maximum recommended PCB copper area for thermal relief with SD945-B?

For optimal thermal performance, Diodes recommends ≥ 400 mm² of 2 oz copper connected directly to both leads on the primary side of the board, with thermal vias under the leads to inner ground/power planes. This achieves near-datasheet RθJL = 8.0 K/W in real-world assemblies, avoiding >10°C junction rise above case temperature.

Does SD945-B require derating when used with capacitive loads?

Yes - the datasheet specifies a 20% reduction in maximum average forward current (IO) when the load is capacitive rather than resistive or inductive. At TC = 120°C, this reduces usable current from 9.0 A to 7.2 A to prevent excessive peak charging currents that could exceed IFSM or accelerate wear-out.

Can SD945-B be used in surface-mount designs?

No - SD945-B is axial-leaded DO-201AD, intended for through-hole mounting. It lacks SMD-compatible terminations or thermal pad geometry. For surface-mount equivalents, consider Diodes' APD2020SCH45 or Vishay's SS10P45, which offer similar 45 V/10 A ratings in SMA/SMB packages.