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DMN2009LSS

20V N-ch MOSFET, 12A, 8mΩ@10V, 9mΩ@4.5V, SO-8, 2W, DC-DC/load switch

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Manufacturer Part：

DMN2009LSS

Package：

SO-8 (5.0 x 4.0 x 1.5 mm, 1.27mm pitch, gull-wing)

Description

The DMN2009LSS from Diodes Incorporated is a 20 V N-channel enhancement-mode power MOSFET in an 8-pin SO-8 package. Key specifications include 20 V drain-source voltage, 12 A continuous drain current, 8 mΩ maximum RDS(on) at VGS = 10 V, 9 mΩ at VGS = 4.5 V, 0.5-1.2 V threshold voltage range, 16 nC typical gate charge at 4.5 V, and 2 W power dissipation. The device uses trench MOSFET technology for ultra-low on-resistance. Operating temperature range is -55°C to +150°C (TJ). The LSS suffix denotes SO-8 package.

Product Introduction:DMN2009LSS Product Introduction

The DMN2009LSS from Diodes Incorporated is a single N-channel enhancement-mode power MOSFET in the industry-standard SO-8 package. With 20 V drain-source rating and 12 A continuous current capability, it targets high-current, low-voltage power management applications including DC-DC converters, load switches, and motor drives.

The ultra-low 8 mΩ maximum RDS(on) at VGS = 10 V (9 mΩ at 4.5 V, 12 mΩ at 2.5 V) is achieved through Diodes’ trench MOSFET technology. At 10 A load, the conduction loss is only 0.8 W (8 mΩ × 10²A), well within the 2 W package rating with adequate PCB copper area.

The 0.5 V minimum threshold voltage ensures the device can be driven from logic-level signals, while the 1.2 V maximum threshold guarantees full enhancement at 2.5 V gate drive. This wide threshold range means the device works well at both 2.5 V and 5 V gate drive, though RDS(on) is significantly lower at 4.5 V and above.

The SO-8 package provides a good balance between current handling and PCB area. The 2 W power dissipation rating assumes adequate thermal design — typically a 1 square-inch copper pour on the drain pins with thermal vias to internal ground planes.

The DMN2009LSS is part of Diodes’ DMN20xx family of 20 V N-channel MOSFETs. Related devices include the DMN2009USS (same die in a different SO-8 variant) and DMN2016UTS (dual N-channel version). The -13 suffix variant denotes tape-and-reel packaging.

For applications requiring automotive qualification, Diodes offers AEC-Q101 qualified variants (identified by ‘Q’ suffix).

Working Principle:DMN2009LSS Working Principle

**N-Channel Trench MOSFET:** The DMN2009LSS uses trench gate technology where vertical trenches are etched into the silicon and the gate electrode is formed inside these trenches. This creates a very large channel width per unit die area, resulting in the ultra-low 8 mΩ RDS(on). The vertical current flow from source (top) to drain (bottom) through the trench structure provides efficient current handling.

**Gate Drive Considerations:** The 0.5-1.2 V threshold range means the device can be driven from logic levels. At VGS = 4.5 V, RDS(on) is 9 mΩ maximum — only slightly higher than at 10 V. This logic-level optimization makes the device suitable for direct MCU GPIO drive in load-switch applications. At VGS = 2.5 V, RDS(on) increases to 12 mΩ, still very low for most applications.

**SO-8 Package Thermal Design:** The SO-8 package dissipates heat primarily through the drain leads (pins 5-8 for single MOSFET configuration) into the PCB copper. The 2 W rating at 25°C ambient requires approximately 1 square inch of 1 oz copper on the drain pads. For higher dissipation, thermal vias connecting to internal copper planes improve thermal performance.

**Body Diode:** The inherent body diode from source to drain has a forward voltage of approximately 0.9 V at 1 A. In synchronous rectifier applications, this diode conducts during the dead time between high-side and low-side switch transitions.

Pin Description:DMN2009LSS Pin Definition and Functions

Pin	Name	Type	Description
1	Source	P/G	Source terminal; typically connected to ground for low-side switching; 12A continuous current path; body diode anode
2	Source	P/G	Source terminal (parallel with pin 1); both source pins must connect together on PCB; reduces parasitic inductance
3	Source	P/G	Source terminal (parallel with pins 1, 2); three source pins reduce package resistance and inductance
4	Gate	I	Gate input; VGS(th) 0.5-1.2V; VGS max ±12V; 16nC gate charge@4.5V; drive with low-impedance driver for fast switching; series gate resistor controls slew rate
5	Drain	O	Drain terminal; 20V max VDS; 12A continuous; 8mΩ RDS(on)@10V; connect to load or inductor; primary thermal path to PCB
6	Drain	O	Drain terminal (parallel with pin 5); solder to copper pour with thermal vias for heat dissipation
7	Drain	O	Drain terminal (parallel with pins 5, 6); three drain pins reduce resistance and provide thermal path
8	Drain	O	Drain terminal (parallel with pins 5-7); all four drain pins must connect together on PCB

Application Scenarios:In which products and applications isDMN2009LSS used

Application	Description
Synchronous Buck Converter Low-Side	Low-side synchronous rectifier in 5V/12V input buck converter; 9mΩ@4.5V minimizes conduction loss; 12A rating covers 10A+ designs; 16nC Qg allows 300-500kHz switching; pair with complementary P-ch or N-ch high-side
High-Current Load Switch	Low-side load switch for 5V/12V subsystems; MCU GPIO drives gate at 3.3-5V; 12A capacity handles multiple loads; 9mΩ RDS(on) gives <100mV drop at 10A; SO-8 provides good thermal dissipation

Alternative Models:What chips are recommended as replacements for DMN2009LSS

Model	Manufacturer	Compatibility	Key Difference
DMN2009USS	Diodes Inc	Package Variant	Same die and specs in different SO-8 variant; verify pinout compatibility before substituting
IRLR3705ZPBF	Infineon	Competitive Alternative	20V N-ch; 15A; 7mΩ@10V; D-Pak (TO-252); higher current; through-hole tab for better thermal; use when higher current needed
SI4486ADY-T1-GE3	Vishay	Functional Equivalent	20V N-ch; 11.6A; 8.5mΩ@10V; SO-8; similar specs; Vishay-sourced alternative