Diodes Incorporated DSS4320T-7

Overview

DSS4320T from Diodes Incorporated is a low V_CE(SAT) NPN surface-mount transistor in SOT-23 package, rated for 20 V V_CEO, 2 A continuous collector current, and 600 mW power dissipation at T_A = 25°C. It delivers 150–220 DC current gain across 0.1–2 A load range and achieves as low as 70 mV saturation voltage at I_C = 0.5 A / I_B = 50 mA, making it suitable for medium-power switching in DC-DC converter output stages.

For engineers reviewing the DSS4320T datasheet, DSS4320T pinout, DSS4320T application, or DSS4320T equivalent, key selection criteria include verified V_CE(SAT) performance at ≥1 A, thermal resistance (R_θJA = 209 °C/W), SOT-23 footprint compatibility, and complementary PNP pairing with DSS5320T in compact power control designs.

Technical Context

This NPN bipolar junction transistor uses epitaxial planar die construction to ensure stable gain and low saturation voltage under pulsed and continuous conduction. Its 20 V V_CEO and 5 V V_EBO ratings support operation in 3.3 V and 5 V logic-controlled switching circuits with margin against transients.

The device exhibits 100 MHz f_T at V_CE = 5 V / I_C = 100 mA and maintains h_FE ≥ 150 up to I_C = 2 A, enabling reliable amplification and hard-switching roles where gain linearity and low on-resistance (R_CE(SAT) = 35–105 mΩ) are critical.

Key Specifications

Pinout & Package

Package: SOT-23 - Surface-mount plastic package with matte tin-plated copper leadframe, UL 94V-0 rated, moisture sensitivity level 1, weight ≈ 0.008 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBT4401 and ZTX851, DSS4320T uniquely balances 2 A continuous current, sub-230 mV V_CE(SAT) at full load, and SOT-23 compactness-making it optimal for space-constrained, efficiency-critical 20 V-class switching where thermal resistance and gain stability matter.

Availability

DSS4320T is available at Aetrix Electronics and suitable for motor drivers, DC-DC converters, LED current sinks, and microcontroller interface circuits requiring stable component supply and RoHS-compliant sourcing.

Supply support for DSS4320T 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, manufacturing, and sales operations across Asia, Europe, and North America.

The DSS4320T belongs to Diodes' low-V_CE(SAT) NPN transistor product line, engineered specifically for high-efficiency, medium-power switching in space-constrained applications such as portable power supplies and motor control modules.

FAQ

What is the maximum allowable pulse current for DSS4320T?

The DSS4320T supports a peak pulse current (I_CM) of 5 A under conditions defined in the datasheet: pulse width ≤ 100 ms and duty cycle ≤ 0.25. This rating applies only when thermal limits are respected; sustained operation above 2 A continuous requires careful PCB thermal design due to its 209 °C/W R_θJA.

Is DSS4320T pin-compatible with DSS5320T?

No - DSS4320T (NPN) and DSS5320T (PNP) share the same SOT-23 package and complementary function but have reversed pinouts: DSS4320T is E-B-C while DSS5320T is C-B-E. Interchanging them without circuit revision will cause functional failure; always verify orientation using top-marking and schematic symbol polarity.

Does DSS4320T require a base resistor in all applications?

Yes - a current-limiting base resistor is mandatory to prevent excessive I_B beyond the 0.5 A absolute maximum rating. For example, driving from a 3.3 V GPIO with target I_C = 1 A and h_FE = 220 requires ~15 kΩ to limit I_B to ~4.5 mA; values must be recalculated for each operating point using V_BE(ON) ≈ 1.2 V and desired overdrive ratio.

Can DSS4320T be used in linear regulator pass transistor applications?

It is not recommended - while DSS4320T can operate in the active region, its 600 mW power dissipation limit and 209 °C/W thermal resistance make it unsuitable for sustained linear regulation above ~100 mW. Applications requiring >100 mW dissipation should use devices with lower R_θJA or TO-220 packages designed for thermal robustness in linear mode.