Diodes Incorporated DSS5540X-13

Overview

DSS5540X-13 from Diodes Incorporated is a 40V PNP bipolar junction transistor (BJT) in SOT89 package, rated for -4A continuous collector current and featuring ultra-low V_CE(sat) of -120 mV at I_C = -0.5A/I_B = -5mA. It serves as a medium-power switching or linear amplification device in DC-DC converters, LED drivers, and load-switching circuits where low conduction loss and thermal efficiency are critical.

For engineers reviewing the DSS5540X-13 datasheet, DSS5540X-13 pinout, DSS5540X-13 application, or DSS5540X-13 equivalent, key selection criteria include its -40V V_CEO, -170 mV V_CE(sat) at 1A, h_FE ≥ 200 at 1A, R_CE(sat) as low as 30 mΩ, and SOT89 thermal performance with R_θJA = 62.5°C/W on 1-inch² copper.

Technical Context

This PNP transistor operates in active or saturation mode with guaranteed BV_CEO = -40V and VEBO = -6V, enabling robust operation in negative-rail switching topologies. Its h_FE ranges from 150 to 350 across I_C = 0.5–2A, supporting stable current gain in both switching and analog amplifier configurations.

Thermal design is supported by dual power dissipation ratings: 0.9W on standard FR-4 and 2W with enhanced 1-inch² copper pad layout, while transient thermal response data confirms suitability for pulsed loads up to 10ms with ≤2% duty cycle.

Key Specifications

Pinout & Package

Package: SOT89 - Surface-mount plastic package with exposed collector tab for thermal conduction and mechanical anchoring; 3-terminal configuration with standardized footprint per Diodes' outline drawing (Doc # DS31653 Rev. 4-2).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP medium-power switching applications.

Compared with MJD44H11T4G and ZTX951, DSS5540X-13 delivers optimal balance of low-loss switching (-170mV @ 1A), compact SOT89 form factor, and production-ready thermal performance-making it preferred for space- and efficiency-critical 24V/4A power nodes.

Availability

DSS5540X-13 is available at Aetrix Electronics and suitable for DC-DC converter high-side switches, LED constant-current drivers, and battery backup load switches requiring stable component supply, consistent parametric performance, and RoHS-compliant manufacturing.

Supply support for DSS5540X-13 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, specializing in high-efficiency power management, signal integrity, and protection solutions for industrial, automotive, and computing markets.

DSS5540X belongs to Diodes' low-V_CE(sat) PNP transistor product line, engineered specifically for medium-power switching and linear regulation applications where thermal efficiency, reliability under pulsed loads, and green material compliance are mandatory.

FAQ

What is the maximum continuous power dissipation for DSS5540X-13 on a standard FR-4 PCB?

The DSS5540X-13 dissipates up to 0.9W continuously on standard FR-4 with minimum recommended pad layout, corresponding to a 125°C junction-to-ambient temperature rise (R_θJA = 139°C/W). This rating assumes no additional heatsinking and ambient temperatures ≤25°C.

Does DSS5540X-13 support automotive-grade qualification?

While DSS5540X-13 is manufactured in IATF 16949-certified facilities and meets AEC-Q101 test requirements, formal automotive qualification requires customer-specific PPAP submission and change control agreement. Diodes provides full support for such programs upon request.

How does the SOT89 package's exposed collector tab affect PCB layout?

The exposed collector tab must be soldered to a dedicated copper pour of ≥1-inch² for optimal thermal performance. Minimum trace width to the tab should be ≥0.5mm, and thermal vias (≥4×0.3mm) are recommended beneath the tab to transfer heat to inner layers or backside copper.

What base drive current is required to fully saturate DSS5540X-13 at 4A collector current?

To achieve V_CE(sat) ≤ -150mV at I_C = -4A, the datasheet specifies I_B = -200mA. This corresponds to a forced beta (I_C/I_B) of 20, ensuring deep saturation and minimizing sensitivity to h_FE variation across temperature and lot.